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Full text of "Principles of geology"

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PRINCIPLES 



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GEOLOGY 



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BEING 



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AN INQUIRY HOW FAR THE FORMER CHANGES OF 

THE earth's surface 



ARE REFERABLE TO CAUSES NOW IN OPERATION 



BY 



CHARLES LYELL, Esq. F.R.S. 

PRESIDENT OF THE GEOLOGICAL SOCIETY OF LONDON 



-*l 



" Amid allthe 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, have 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." 

Playfair, Illustrations of the Huttonian Theory, ^ 374. 



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IN FOUR VOLUMES. 



VOL. I. 



THE FIFTH EDITION. 



LONDON: 

JOHN MURRAY, ALBEMARLE STREET. 

1837. 



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London ; 

Printed by A. SpomswooDfl, 

New- Street- Square. 



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PREFACE. 



The 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 

r 

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 

w 

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 : 



L 



r 

1st Vol. in octavo - 

2d Vol. do. 

1st Vol. 2d edition in octavo 



2d Vol. 2d edition 
3d Vol. 1st edition 



do. 
do. 



New edition (called the 3d) of the 

w^hole work in 4 vols. 1 2mo. 
4th edition, 4 vols. 12mo. - 

A 2 



- Jan. 1830 

- Jan. 1832 

1832 

- Jan. 1833. 
• May 1833. 



- May 1834. 

- June 1835, 



r1 



1 

I 



i 



IV 



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 Hsts 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. 



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4 




List of the principal Alterations and Additions in the 



Fifth Edition as compared to the Fourth. 



Vol. I, 



Deluge of the Chinese - - - - 

Legend of the Seven Sleepers . - - - 

Humboldt on preservation of animals in frozen mud 
Stranding of icebergs on west coast of Iceland - 
Raised beaches in Carlingford Bay, Ireland 
Omission of remarks on the origin of the valleys of the 

Moselle and Meuse - . - - . . 

Account of Edmonstone Island corrected 



" p. 10 

- 119 

- 154 
173 

215 



264 
360 






PREFACE. 



Arago on causes of currents, and on relative level of the 



Vol. I. 



Red Sea and Mediterranean - 
On the formation of Shingle beaches 



- p. 387 

428 



VoL II. 



recast 



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



57 



152 



Dr, Daubeny on a volcanic band across the Italian 
peninsula -"---__ 

Theory of elevation-craters recast, with many additions 
and new illustrations - - _ 

Account of the earthquake in Chili, February 1835, added- 
with Map of Chili and plan of the Harbour of Concep- 
tion - - _ _ . _^ 

Dr. Meyen on proofs of elevation of land in Chili, 1822 - 191 
On the effects of earthquakes in the excavation of valleys, 



183 



238 
292 
302 



Sir John Herschel on the vegetation of seeds after exposure 

to great heat - - - - - 

Dr. Beck on the great range of some species of testacea - 

Erman on the level of the Caspian - - « 

Account of Submarine Forests, transferred to this place 
from Chapter xvi. - 



Vol. IIL 



14 

56 

126 



226 



Vol. IV. 



Loess of the Valley of the Rhine, the whole recast with 
additions 

Slope of recent strata in the modern delta of the Kander 
in Lake of Thun - - . 

Crag of Norfolk and Suffolk, and overlying deposit. The 
whole of this chapter recast - . . 

M. Dufr^noy on the tertiary strata of the basin of the 
Gironde _ _ 



29 



69 



71 



Note on the latest opinions respecting an alleged difference 
of level between the Caspian and Black Seas -' 

Professor Sedgwick and Sir J. Herschel on the causes 
of the cleavage of rocks 



121, 124 



202 



. 357 to 359 



A 3 




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VI 



PREFACE. 



New Wood Cuts in the Fifth Edition. 



Vol: I. 

1 Pleurotoma rotata p, 143 

2 Map of Siberia - - 149 

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 -m - 154 

7 Plan of the Isle of 



Pal ma 



- 155 




Diagrams to illustrate ,- 171 
the elevation-craterJ ih. 
theory - - tl76 



1 1 Map of Chili - 

12 Map of Harbour of 

Conception - 

13 Map of Calabria 

14 Map of Sweden and 



* 184 



- 186 
" 211 



the Baltic 



- 290 
Vol. III. 

15 Meandrina labyrinthica 276 

16 Astrea dipsacea - ib, 

17 Madrepora muricata 277 

18 Caryophylliafastigiata ib. 



19 Pontes clavaria 

20 Oculina hirtella 



ib, 

- ih. 

Vol. IV. 



21 View of worn lime- 

stone columns in 
Niapisca island 

22 Succinea elongata 

23 Pupa muscorum 

24 Helix plebeium 

25 Catillus Cuvieri 



21 

33 
ib, 
ib. 



Vol. IV. 

26 Crania Parisiensis p. 272 

27 Plagiostoma Hoperi ib. 

28 P. spinosum - - ib. 

29 Terebratula Defrancii 273 



30 Ostrea carinata - 



ib. 



31 Terebratula octoplicata ib. 

32 T. pumilus - ~ ib. 

33 T. carnea - - ib. 

34 Ostrea vesicularis - ib, 

35 Belemnites mucrona- 



tus 



- 274 



36 Baculites Faujasii 

37 B. anceps 

38 Ammonites rhotoma- 



ib, 
ib. 



gensis - 



ib. 



39 Beloptera belemnitoi- 



dea 



- 275 



40 Hippurites bioculata ' 

and H. radiosa - 276 



41 Terebratula Ivra 

42 Pecten 5-co3tatus 



ib. 

ib. 



43 Turrilites costatus p. 277 

44 Cypris spinigera 

45 C. Valdensis 

46 C. tuberculata 

47 Gryphaea virgula 

48 Ostrea deltoidea 

49 Section of Nerinoea 

hieroglyphica 



- 282 

- ib. 

- ib. 

- 288 

- ib. 



- 289 



50 Cast of Diceras arie- 
tina - - - 



ib. 



51 Terebratula spinosa - 290 



52 Pholadomya fidicula 

53 Belemnites hastatus 

54 Gryph^a incurva 



ib, 
ib. 

291 



- 272 55 Nautilus truncatus - iti 



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PREFACE. 



■ • 



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Vol. IV. 
56 Hybodus reticulatus p, 292 



57 Acrodus nobilis 

58 Avicula socialis 



z6. 



59 Orthoceras laterale - 295 



Vol. IV, 

60 O. giganteum - p. 295 

61 Calymene Blumenba- 

chii 

62 Asaphus Buchii 



- 299 



Glossary. — Being informed by several readers 

r 

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, 

r 

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, 
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. 



A 4 



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« ■ « 



Via 



PREFACE. 




ir. 



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, 

J 

from the times of the earliest known writers to 

r 

our own days (Chaps. II. III. IV.). From this 
historical sketch it appears that the first cultivators 

r 

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. L), 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. VL 



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PREFACE. 



VII. VIII.)? 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 fundamental ques- 



tion are freely enlarged upon, in 



hope of 



Stimulating: curiosity; and the author is aware 



fc) 



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 enei^gy as those 
now acting : or, at least, he will perceive that the 
opposite hypothesis is very questionable ; and if 



so, he will enter upon 



study 



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- 

■ r 

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 withi 



historical era. 



divided into two parts. In the first, an account is 
given of the observed effects of aqueous causes, 

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PREFACE. 



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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 IL 
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. L 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 

r 

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 



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PREFACE. 



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XI 



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(Chaps. V. to X.). Whether 



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 

h 

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 bein^ 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 aaents, 
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. 






/■ 

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PREFACE. 



t » 



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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- 

r 

dern times by running water and subterranean 
heat. Hence the utility of one of the preceding 
treatises (Book 11.) 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 

t 

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 scoriae, and of stone 

f 

r 

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 



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PREFACE. 



* • • 



XUl 



going on, by which certain individuals of existin 
species become fossil, and this information 
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 
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- 
tmction 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 



m 



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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. 



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London, October, 1836 



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^ 



ABRIDGED TABLE OF THE CONTENTS 




OF THE WHOLE WORK. 




Book T. Chap. I. Objects and Nature of Geology 



A 



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( 



II. III. IV. Historical Sketch of the Progress of 

Geology - - .. 

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 - 
IX. The same Question considered in refer- 
ence to the Theory of the Progressive 
Development of Organic Life 
Changes of the Inorganic World now in 
Progress — Aqueous Causes — Ac- 
tion of running Water 
11. Rivers — Floods 

III. Phenomena of Springs 

IV. Deposits in Deltas of Lakes and inland 

Seas - ^ 

V. Oceanic Deltas - . . 



Vol. I. 



6 



110 



138 



Book IL Chap. I. 



227 



259 
279 
300 



336 



S57 



VI. VII. Tides and Currents —DestroyingEffects 380 



VIII, Tides and Currents 

Effects 

IX. Igneous Causes 
X. XL 



Vol. 1 1. 



Reproductive 



XII 



Volcanic Regions - 
Volcanic District of Naples 
Etna — Its modern Lavas 



22 
37 
61 






XVI 



CONTENTS. 



Book II. 



Vol. II. 



Chap. XIII. Lancerote 



Submarine Volcanos 



Theory of Elevation Craters 
XIV. Earthquakes of the last Fifty Years - 

XV. Earthquake of Calabria in 1783 
XVI. Earthquakes, continued — Temple of 

Serapis - 
XVII. Elevation and Subsidence of Land with- 
out Earthquakes - - - 
XVIII. Causes of Volcanic Heat 
XIX. Causes of Earthquakes 



- p. 138 
181 
210 



248 



286 
307 
331 




Book III. Ch. I. Changes of the Organic World now in 

Progress — Reality of Species 
II. Theory of Transmutation of Species 

untenable « - - 

III. Limits of the Variability of Species 




360 



IV. Hybrids 



382 
405 
422 



Vol. III. 



1 



V. VI. VII. Geographical Distribution of Species - 

VIII. IX. Changes in the Animate World, which 

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

of Species can now be in Progress - 
XII. Modifications in Physical Geography 

caused by Plants, the inferior Ani- 
mals, and Man - - - 

XIII. How Plants and Animals become Fossil 

in Peat, Blown Sand, and Volcanic 
Matter - - . - 

XIV. Burying of Fossils in Alluvial Deposits 



XV. 



and Caves _ - _ 

Imbedding of Organic Remains in the 
Deposits of Seas and Lakes 
XVL How the Remains of Man and his 

Works are becoming Fossil beneath 
the Waters 



1 



77 



120 



142 



153 



176 



196 



21S 



23S 



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CONTENTS. 



• • 



XVll 



■ 



Book III. 



Vol. III. 




Chaf. XVII. How Freshwater and Marine Plants 

and Animals are becoming Fossil in 
Subaqueous Strata - 



XVIII. Formation of Coral Reefs 



- p. 258 

274 



« 




8 



Book IV. Ch. L On the Connexion of the Second and 

Third Books with the Fourth 
II. General Arrangement of Materials in 

the Earth's Crust, and Rules for 
determining the relative Ages of 
Rocks _ - . 

III. Discovery of Tertiary Groups of succes- 
sive Periods - - _ 

IV. Different Circumstances under which 

the Secondary and Tertiary Form- 
ations may have originated 
V. Subdivision of Tertiary Formations con- 
sidered chronologically 

VI. Newer Pliocene Formations _ Sicily 
VII. VIII. Rocks of tjie same Age in Etna 

IX. Changes since the Formation of the 

Newer Pliocene Strata in Sicily 



1 



X. Marine and Volcanic Newer Pliocene 

Formations 
XI. Freshwater and Alluvial of the 



same 




Period 



XII. Older Phocene Formations 
XIII. Crag of Norfolk and Suffolk - 

r 

XIV. Volcanic Rocks of the Older Pliocene 

Period - - . _ 

XV. Miocene Formations — Marine 
XVI. Alluvial — Freshwater — Volcanic .- 



XVIL Eocene Formations 
XVIII. . __^ 



I 



XIX. 



Freshwater 
Paris Basin 



Volcanic Rocks 

Formations of different Coun- 
tries and of England 



303 



311 



332 



341 



356 
382 

397 



433 



114 
134 
143 
164 

184 



208 



\\ 





T 



XVUl 



CONTENTS. 



* 



Book IV. Vol. IV. 

Ch. XXI. XXII. Origin of the English Eocene Form- 
ations and Denudation of the Weald p. 220 

XXIII. Secondary Fornxations _ . 268 

XXIV. Analogy of the older Fossiliferous to 

the Tertiary Strata - - 307 

XXV. Relative Antiquity of Mountain Chains 320 
XXVI. On the Rocks commonly called Pri- 



mary — 
XXVII. On the same 



Un stratified 



Stratified 



336 
353 



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DIRECTIONS TO THE BINDER, 



Plate 1 

2. 



3. 
4. 
5. 
6. 



7. 
8. 
9. 



10. 

11. 

12. 

13. 
14. 

15. 



Frontispiece to face Title-page, Vol. I. 



Vol. I. 

p. 194 
214 



Vol. II. 



47 

61 

194 

195 



Vol. III. 



382 
407 
408 



Vol. IV. 

59 
90 

115 
176 

177 
220 



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PRINCIPLES OF GEOLOGY. 



BOOK J. 




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1 



CHAPTER I. 



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

Geology is the science which investigates the suc- 
cessive changes that have taken place in tlie organic 
and inorganic kingdoms of nature : it inquires into the 
causes of these changes, and the influence which thev 
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 
"man nature, by instituting a comparison between 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 eifects 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. 



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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 mhabitants, their peculiar manners, laws, and 
religious opinions. 

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 peculiarities, ma be 
distinctly referred. On the other hand, many diftin! 
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 



But far more astonishing and un- 



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Ch. r.] ITS RELATION TO OTHER PHYSICAL SCIENCES. 



3 



lake or in the ocean, or 
testacea and corals. 



to the prolific increase of 



To select another example, we find in certain 

localities subterranean deposits of coal, consisting of 

J^egetable matter, formerly drifted into seas and lakes. 

These seas and lakes have since been tilled 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 



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' <JEOLOGY COMPARED TO HISTORY. 



[Book I, 



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VI 



archives of former ages. But as such extensive ac- 

r 

quisitions are scarcely within the reach of any indi- 
vidua!, it is necessary that men who have devoted 

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their lives to different departments should unite their 
efforts ; and as the historian receives assistance from 

r 

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. 

r 

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 undesignedly 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- 
jpied by invading armies, and the former method of 
constructing military defences : the Egyptian mummies 

on the art of embalming, the rites of 



throvv 



light 



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 being 
free from all suspicion of misrepresentation. We may 
be deceived in the inferences which we draw, in the 






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Ch, I.] 



GEOLOGY DISTINCT FROM COSMOGONY. ' 



5 



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r 

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- 

pretatlon, 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-defiined 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 

D 
esmarest 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, 
berore 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 



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CHAPTER IL 

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. — The 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 Menu," the sacred volume of the Hin- 

r 

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, changino- 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 



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Ch. II.] 



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. 

Menu 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 
locomotive and immoveable creatures. 



It 



IS 



^ 



then declared that there has been a long 
succession of manwantarasy 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 Menu 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- 



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

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8 



ORIENTAL COSMOGONY. 



[Book I. 



cidence between the oriental dogmas and observed 
facts. Tills 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 coniec- 
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 observ- 
atlon 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 



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Ch. IL] 



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 upHfted so as to form 
part of high mountain chains. Those modern writers, 
wno are disposed to disparage the former intellectual 
^ovancement and civilization of eastern nations, may 
concede some foundation of observed facts for the 
curious theories now under consideration, without in- 
aulging 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, 
^^e 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 
executed by oriental monarchs in very remote eras, 
fhey formed canals and tanks on a magnificent scale, 



^nd we know that in 



) 



(th 



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 



« 



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Herodot. Euterpe, 12. 



t This circumstance is mentioned in a Persian MS. copy of 

the historian Ferishta, in the library of the East India Company, 

re ating to the rise and progress of the Mahomedari empire in 

India, procured by Colonel Briggs from the library of Tippoo 

ultan m 1799^ and has been recently referred to at some length 



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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 exaorsrerated accounts of those 



&& 



partial, but often dreadful, catastrophes, w^hich 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 calaniitieSj re- 
curring at distant intervals of time, in the present 
course of 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 
unaginatlon 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. li, 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 throu-Th 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 thern 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. 




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Ch. II.] 



ORIENTAL COSMOGONY. 



11 



niore than 2000 years before our era^ has been Iden- 
tified by some persons with the universal 



deluge 
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 



1 



The great Yu was celebrated for having 



nterrupting the business of agriculture, rather than 
as involving a general destruction of the human race. 

" 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 

I 

bursting of the banks of an artificial canal, frito 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 



4 

* See Davis on « The Chinese/' published by the Soc. for the 
DifFus. of Use. Know. vol. i. p. 128. 

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12 



EGYPTIAN COSiMOGONY 



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[Book I. 



ap 



■ 

dancing, the destruction of the world and the 
preaching 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 
mmds 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, t 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. X The returns of great catastrophes 
were determined by the period of the Annus Maanus, 

* Humboldt et Bonpland, Voy. Relat. Hist. vol. i. p. 30. 
f Prichard's Egypt. Mythol. p. 177. 

\ Plut. de Defectu Oraculorum, cap. 12. Censorinus de Die 
Natali. See also Prichard's Egypt. Mythol, p. 182. 



9 

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Ch. II.] 



EGYPTIAN COSMOGONY. 



13 



or great year, — a cycle composed of the revolutions 
Or the sun, nrioon, and planets, and terminating when 
these return together to the same sign whence they 
^ere supposed at some remote epoch to have set out. 
-I he 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 Timseus 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, 
niankind 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 

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 deluo-e, 
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 
irom a state of innocence. Towards the termination of 
each era the gods could nolonger bear with the wicked- 
ness of men, and a shock of the elements or a deluge 
overwhelmed them ; after which calamity, Astrea again 



iron age. 



descended on the 



t 



The connection between the doctrine of successive 



* Prichard's Egypt. Mythol. p. 182. 



t Ibid. p. 193 



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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- 
Heved 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 Hke 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 a state 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 Timaus. 



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Ch. II.] 



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 

■t 

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 ncien 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- 








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16 



PYTHAGOREAN SYSTEM, 



[Book Ti 



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- 



Mundan 



race of birds."* 



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, " Haw sable-plumaged Night con- 
ceived m the boundless bosom of Erebus, and laid an 
egg, from which, in the revolution of ages, sprung 
Love, resplendent with golden pinions. Love fecund 
dated the dark-winged chaos, and gave origin to the 

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 
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. 

J 

* Aristophanes, Birds, 694. 



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Ch. II.] 



, PYTHAGOKEAN SYSTEM. 



17 



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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- 
l^ensive 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 
Jiot 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 

r 

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 boVn, means simply 
that a thing begins to be something different fi'om what 
it was before ; and dying, is ceasing to be the same 
thing. Yet, although nothing retains long the same 



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18 



PYTHAGOREAN SYSTEM. 



[Book 1. 



image, the sum of the whole remains constant." These 
general propositions are then confirmed by a series of 
examples, all derived from natural 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 



Asia, 



My 



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

8. Islands have become connected with the main 
land, 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 accordin^^ 
to tradition Sicily, the sea having carried away the 
isthmus. 

* Eluvie mens est deductus in aequor, 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. 

+ 

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



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Ch. II.] 



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 Trcezen in the Pelo- 

r , 

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- 

m 

mala, in the Tuscan Apennines; and several other places. 

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

\ 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. 



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20 



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. 

The various causes of change in the inanimate 
world having been thus enumerated, the doctrine of 
equivocal generation is next propounded, as illus- 
tratmg 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 m 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 brino-jnjr 
about a complete change. But the fiction expressed in th 
before quoted from Menu, 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- 



e verses 



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Ch. II.] 



ARISTOTELIAN SYSTEM. 




i^ 



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. Tlie deluge 

— L 

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.-j- 
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 

r ^^^ ^^ ^^ 

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 Maeotis 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 



* Moteor. lib 



cap, 12 



I De Die Nat. 




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22 



ARISTOTELIAN SYSTEM. 



[Book I. 



earth, 



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 
--h he sajs, " are so slow in comparison to the du- 
*"7'; °^ °"' ^^^e«' that they are overlooked (x«v0av.O; 
and the migrations of people after great catastrophes, 
and their removal to other regions, cause the event to 
be forgotten." f 

Vvhen 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 



In the 



ever. 



first sentence he says, " The distribution of land and 
sea in particular regions does not endure throughout 
all tune, but it becon^es 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 
--" The places where they rise were once dry, 
and there is a limit to their operations ; but there is 

g^ also of all other rivers ; they spring 
up, and they perish ; and the sea also continually 
deserts some lands and invades others. The same 
tracts, therefore, of the earth are not, some always 
sea, and others always continents, but every thin<r 
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 



none to time. 



• Lib. ii. cap. 14, 1,5, and 16. 



t Ibid. 



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Ch. II.] 



CREATION OF SPECIES. 



23 



•degree, deduced from their 



own observations, the 



th 



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- 
mams were inclosed in solid rocks, although observed 
Dy some, and even made the groundwork of geoloo^ical 
speculation, never stimulated the industry or guided 
the inquiries of naturalists. It is not impossible that 

e 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 organic 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 

e 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 
he given to the earth."* 

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

J 

nine ex Integro animal generabitur, dabiturque terris homo 



th 



insciusscelerum. 

+ Thi 



Quaest. Nat. iii. c. 29. 



p . "**=» xi-cgius Aiuiessor oi oyriac ana Arabic at 

y ere, m l6S5^ he published a Latin translation of many 
rabian MSS. on different departments of philosophy. This 
^ork has always been considered of high authority. 



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24 



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 0^ 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 vears, 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. 



J) -1 



Theory ofStrabo. — ks we learn much of the tenets 
of the Egyptian and oriental schools in the writings of 
the Greeks, so many speculations of the early Greek 



I 

1 





^ 




r 

Gerbanltse docebant singulos triginta sex mille annos qua- 
dringentos, viginti quinque bina ex singulis animalium speciebus 
produci, marem scilicet ac feminam, ex quibus animalia propa- 
ganUir, buncque inferiorem incolunt orbem. Absoluta autem 
ccelestium erbium circulatione, quas illo annorum conficitur spatio, 
iterum alia producuntur animalium genera et species, quemad- 
niodum et plantarura aliarumque rerum, et primus destruitur ordo, 
sicque in infinitum producitur. — Histor. Orient. Suppl. per 
Abrabamum Eccbellensum, Syrum Maronitam, cap. 7. et 8. ad 
calcem Chronici Oriental. Parisiis, e Typ. regia, 1685, fol. 

I bave 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 

r 

that twenty-five new species only were created at a time; a con- 
struction which the passage will not admit. Mem. sur THist. 
Nat. deT Italic, vol. i. p. 20 






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Ch. II.] 



THEORY OF STRABO. 



25 



r 

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 
'^ost difficult problems in geology, viz. by what causes 
marine shells came to be plentifully buried in the earth 
^t 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, 
J'lvers, and wells in Asia had failed during a season of 
drought. Treating this conjecture with merited dis- 
I'egard, 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 
^p 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 
mland 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. 



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THEORY OF STRABO. 



[Book I. 



his own, the profoundness of which modern geologists 
are only beginning to appreciate. '' It is 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.* If is proper/' he observes in 
continuation, ^' to derive our explanations from things 
which are obvious^ and in some measure of daily occur- 
renccy such as deluges^ earthquakes^ and volcanic 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 



# u 



Quod 



hoc attollitur aut subsidit, et vel inundat 



qusedam loca, vel ab iis recedit, ejus rei causa non est, quod alia 
aliis sola humiliora sint aut altiora; sed quod idem solum modo 
attollitur mod& deprimitur, simulque etiam modo attollitur modo 
deprimitur mare : itaque vel exundat vel in suum redit locum." 

Postea, p. 88. « Restat, ut causam adscribamus solo, sive 
quod mari subest sive quod inundatur ; poti^s tamen ei quod 
mari subest. Hoc enim multo est mobilius, et quod ob humidita- 
tem celerius mutari possit"— Strabo, Geog. Edit. Alraelov. 
Amst. 1707. lib.i. 

f Volcanic eruptions, eruptiones flatuum, in the Latin transla- 
tion, and in the original Greek, ava<^va-nfj,a,r<i, gaseous eruptions ? 
or inflations of land ? — ibid., p. 93. 






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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- 
^"g 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 
oy 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 Strabof, 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. Caesar, it will be remembered, 
says that they made use of Greek letters in arithme- 
tical computations. :j: 

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



* Strabo, lib. vi. p. 396. 
\ L. vi. ch. xiii. 



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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 convulsionsj 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. 




I 








H • 



29 



.] 



iiii 



CHAPTER III. 



HISSTORY OF THE PROGRESS OF GEOLOGY 

Arabian writers of the tenth century 
Cosmogony of the Koran — Kazwini 



continued. 



Avicenna — Omar 
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 — 
pooke's Theory of Elevation by Earthquakes (p. 47.)— Of 



\ 



' 3ost species of animals — Ray 



Woodward's Diluvial Theory (p. 54.) — Burnet 



Physico-theological writers 

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 



Whitehurst — Pallas 



Puchsel (p. 76.) 
Saussure. 



Fortis 



Testa 



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 Mamun, son of the famous Harun-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, i v. section iii. 

c 3 




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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, 

r 

" 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 

F 

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 HofFhas 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 

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



W 







* 















Ch. III.] 



OMAR — THE KORAN. 



31 



*pp 



1 



1 




iiistorical 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 
^pon 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 
^t 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.f There is no 

* VonHoff, Geschichte der Veianderungen der Erdoberflache, 
vol. i. p. 406.5 "vvho cites Delisle, bey Hismann Welt-und Volker* 
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 
ttiaintained that the Koran was increate, and had subsisted in the 

E 

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 
M^ecca, and accused their opponents of believing in two eternal 
beings. The opinions of each of these sects were taken up by 
difrerent caliphs in succession, and tlie 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. 



f Koran, chap, xli. 



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32 



OMAR — THE KORAN. 



f [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 th^ 
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, heaven, withhold 



We 



+ 



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 



* Sale's Koran, chap. xi. see note. 



t Ibid. 



^ Kossa, appointed master to the Caliph Al Mamud, was au- 
thor of a book, entitled " The History of the Patriarchs and Pro- 
phets, /rom ^Ae Creation of the ^orld.''— Mod. Univ. Hist, vol.ii. 
chap. iv. 

r 

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




t'i 






I 

■■1 

I 





^ 







Ch. III.] 



MOHAMMED KAZWINI. 



33 



I 



In 

The ground 



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, ' It is indeed a mighty city/ replied he, ^ we 
know not how long it has existed, and our ancestors 
^ere 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, 
demanded of a peasant who was gathering herbs, upon 
its former site, how long it had been destroyed, 
sooth, a strange question !' replied he. * 
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 
* Its rise is lost in remote antiquity : we are ignorant 



me 



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34 



FRACASTORO. 



[Book 1. 



how long It has existed, and our fathers were on this 
subject as ignorant as ourselves.' '' 



Ba 



F. 



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 Fracastorof, who declared his opinion, that fossil 
shells had all belonged to living animals, which had 
formerly lived and multiplied where their exuviee are 
now found. He exposed the absurdity of having 
recourse to a certain "plastic force," which it was 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. 

t Museum Calceol. 






n 





\i 



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5 




--^-. 





■I 




Ch. III.] 



EARLY ITALIAN WRITERS. 



35 



^ven though doubts should for a time have remained 
^n 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 
^^^e disregarded, and the talent and argumentative 
powers of the learned were doomed for three centuries 

r 

*o be wasted in the discussion of these two simple and 
preliminary questions : first, whether fossil remains had 
^ver 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 
e 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 
he 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 
nionks remained in undisturbed enjoyment of rich 
grants of land bequeathed to them by pious donors, 
■^"0, in the preamble of deeds beginning " appropin- 



th 



quante mundi termino 



9> 



" 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 




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36 



ANTIQUITY OF THE EARTH. 



tBook I. 



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 

■ X 

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. 






ii^ 



\ 




M» 



i^ 



I 




I 








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. 




- ^ 



^ir??~"~ 




;il 



I 



Ch. III.] 



EARLY ITALIAN WRITERS. 



37 



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 
^n 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 
niet his arguments by feigning 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 
termentation by heat, gave birth to fossil organic shapes, 
^^t Mattioli had come to the conclusion, from his own 
observations, that porous bodies, such as bones and 
sbells, might be converted into stone, as being per- 
nieable to what he termed the " lapidifying juice/' 
^^ 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- 
nients of terrestrial exhalations." Although celebrated 
as a professor of anatomy, he taught that certain tusks 
oi 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 



Monte 



at Rome were 



natural impressions stamped in the soil* In the same 



M 



ot the fossil shells preserved by Pope Sixtus V. in the 



Museum 

they were mere 



atican, expressed an opinion that 
stones, which had assumed their 



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NATURE OF ORGANIZED FOSSILS. 



[Book I. 



peculiar configuration from the influence of the hea- 
venly bodies ; and Olivi of Cremona, who described 

J 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" 



( 



Philosophy) 



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 



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 soilf ; and in the 
following year (1597), Simeone Majoli :|: went still 

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



I De Metallicis. 



\ Dies Caniculares. 



I 



^ 



i.': 




ch. in.] 



PALlSSy— COLONNA. 



39 



farther; and, coinciding for the most part with the 
views of Cesalpino, suggested that the shells and sub- 
wiarine matter of the Veronese, and other districts, 
^ight have been cast up upon the land by volcanic 
^plosions, like those which gave rise, in 1538, to 
Monte Nuovo, near Puzzuoli. This hint seems to 
nave been the first imperfect attempt to connect the 
position of fossil shells with the agency of volcanos, 
^ system afterwards more fully developed by Hooke^ 
■'-'azzaro Moro, Hutton, and other writers. 

Iwo years afterwards, Imperati advocated the ani- 
"^ai origin of fossilized shells, yet admitted that stones 
could vegetate by force of " an internal principle ; " 
^^d, as evidence of this, he referred to the teeth of 

®^? and spines of echini found petrified.*^ 
Palissy, 1580. — Palissy, a French writer on « The 
^^^gm of Springs from Rain-water,'' and of other 
scientific works, undertook, in 1580, to combat the 

otions 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, 
ft the French Academy, he pronounced his eulogy, 
Nearly a century and a half later, " who dared assert,'' 
"aris, that fossil remains of testacea and fish had 
once belonged to marine animals. 

^abio Colonna. — To enumerate^ the multitude of 

lan writers, who advanced various hypotheses, all 

equally fantastical, in the early part of the seventeenth 

^y> Would be unprofitably tedious; but Fabio 
tolonna deserves to be distinguished ; for, although 
fte 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 

* Stpria Naturale. 



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40 



STENO. 



tBook I. 



tacea.* 



and ammonites were mere clay, altered into such forms 
by sulphureous 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 belonge'd to marine, and some to terrestrial, tes- 

Steno, 1669. — But the most remarkable work of 

that period was pubhshed 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 Solidura naturaliter content© (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, 

the general reception of enlarged views in the 

^^^^ 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, 
reference to this controversy, Steno had dissected a 



to 

science. 



In 



Medite 



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 

J 

* Osserv. sugll Animali aquat. e terrest. 1626. 






^ 



V 




4 



n 





I 



n 





*l 



Ch. III.] 



STENO. 



41 



J 

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 
basses, 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, 
tile last containing reeds, grasses, or the trunks and 
l^ranches of trees. He argued in favour of the original 
^onzontality of sedimentary deposits, attributing their 
Present inclined and vertical position sometimes to the 
escape 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 
^^st successively have acquired six distinct configura- 
tions, having been twice covered by water, twice laid 
d^y with a level, and twice with an irregular and uneven 
surface.* He displayed great anxiety to reconcile his 
iiew views with Scripture, for which purpose he pointed 
to certain rocks as having been formed before the ex- 
istence of animals and plants; selecting unfortunately 
^s examples certain formations of hmestone and sand- 
stone in his own country, now known to contain, though 
sparingly^ the remains of animals and plants, 
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. 

Sex itaque distinctas Etrurije fades agnoscimus, dum bis 
fluida, bis plana, et sicca, bis aspera fuerit, &c. 



strata 



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42 



SCILLA. 



[Book I. 





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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 da)^ Scilla gave way to the 
popular persuasion, that all fossil shells were the effects 

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 

* 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," 



Mosaic 




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Ch. III.] 



DILUVIAL THEORY. 



43 



establish this preliminary point. Such a comptomising 
policy was short-sighted, since it was to little purpose 
tnat the nature of the documents should at length be 
correctly understood, if men were to be prevented 

^om deducing fair conclusions from them. 
^^luvial Theory. — The theologians who now en- 

^^ed the field in Italy, Germany, France, and England, 
^^e innumerable; and henceforward, they who refused 

^ Subscribe to the position, that all marine organic re- 
^ains were proofs of the Mosaic deluge, were exposed 

^ the imputation of disbelieving the whole of the 
sacred writings. Scarcely any step had been made in 

Pproximating to sound theories since the time of 

^acastoro, more than a hundred years having been 

^st, in writing down the dogma that organized fossils 
^ere mere sports of nature. An additional period of 
^ century and a half was now destined to be consumed 
^^ exploding the hypothesis, that organized fossils had 
^^^ been buried in the solid strata by the Noachian 
^ood. Never did a theoretical fallacy, in any branch 
Science, interfere more seriously with accurate 

^servation and the systematic classification of facts. 

^ J'ecent times, we may attribute our rapid progress 
chiefl 



of 



y to the careful determination of the order of 



succession 
difF( 



in mineral masses, by means of their 
erent 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 
vane y of causes acting throughout a long succession 
of epochs. They saw the phenomena only as they 
desired to see them, sometimes misrepresenting facts, 






I 




Hill 





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DILUVIAL THEORY — QUIRINL 



[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 f ; and 

* De Testaceis fossilibus Mus. Septaliani. 

I 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 



I 



\ 



I.-U 




J 



Ch. III.] 



PLOT — LISTKR, 



45 



still less could the testacea, as some pretended, have 
lived in these diluvian waters; for " the duration of the 
noou 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 
;^oachian 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 
"^ollusca, the same crystallizing process might be ef- 
fected on the land; and that, in the latter case, the 
germs of the animals might have been disseminated 
through the substance of the rocks, and afterwards 
*^eveloped by virtue of humidity. Visionary as was 
^^^^ doctrine, it gained many proselytes even amongst 
"e more sober reasoners of Italy and Germany; for it 
Conceded that the position of fossil bodies could not 
"e accounted for by the diluvial theory. 

Plot — 'Lister^ 1678. — In the mean time, the doc- 
•■^i^e that fossil shells had never belonged to real 
^^imals maintained its ground in England, where 
^"e agitation of the question began at a much later 
Penod. Dr. Plot, in his " Natural History of Oxford- 
shire" (1677), attributed to a " plastic virtue latent 
in the earth" the orisin of fossil shells and fishes; and 
ister, to his accurate account of British shells, in 
^78, added the fossil species, under the appellation of 



/ 



y> iJoyle inferred that, when the waves were six or seven feet 
f ^^® *"6 surface of the water, there were no signs of agit- 

^ clepih of fifteen fathoms ; and that even during heavy 

' *"6 motion of the water was exceedingly diminished 

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

some of his informants, that there were currents running in oppo- 

me directions at different depths. _ Boyle's Works, vol. iii. p. 1 10. 
-London. 1744. 



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46 



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 " Protogoea' 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. 



3 





n 









V 








Ch. HI.] 



HOOKE. 



47 



r 

from aqueous solution/' * By the repetition of similar 







(th 



ions of new strata were produced, until 



at length these causes were reduced to a condition of 
quiescent equilibrium, and a more permanent state of 



B^ooke 



t 



Works 



ooke, M,D.," well known as a great mathematician 
l^d natural philosopher, appeared in 1705, containing 
A Discourse of Earthquakes," which, we are in- 
oj^nied by his editor, was written in 1668, but revised 
subsequent periods. :|: Hooke frequently refers to 
€; best Italian and English authors who wrote before 
^s time on geological subjects; but there are no pas- 
^ges 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- 
ent of certain groups of strata. His treatise, however, 
the most philosophical production of that age, in 
S^yd to the causes of former changes in the organic 
^d morganic kingdoms of nature. 
" However trivial a thing," he says, " a rotten shell 
^y appear to some, yet these monuments of nature 

^ nae jam duplex origo intelligitur primorum corporum, una, 

^ Ignis fusione refrigescerent, altera, cum reconcrescerent 
"" solutione aquarum. 

I xieaeunte mox simili caus4 strata subinde alia aliis impone- 
rentur, et f • • t 

quie • teneri adhuc orbis s^pius novata est. Donee 

^ us causis, atque Eequilibratis, consistentior emergeret 
his Pr ^^^^^' ^ ^^^ ^" ^^'^ analysis of the views of Leibnitz, in 
fK« J° °^'^^' ^^^ ^^- Conybeare's Report to the Brit. Assoc, on 
the Progress of Geological Science, 1832. 

memo'^*"^^^^ ^^^ ^^^"^ ^^^^ ^"^ ^^^ death, in 1703, he read several 
, . ^ ® Royal Society, and delivered lectures on various 

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




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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 thevfiy 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 froni 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 aerial and aquatic animals : for those animated 
bodies, whether vegetables or animals, which were 
naturally nourished or refreshed by the air, would be 

r 

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








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Ch. HI] 



HOOKE ON EXTINCT SPECIES. 



49 



destroyed by the water," &c.* Turtles, he adds, and 
siich 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 earth's rotation, *« a shifting of the earth's centre 
^t 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 
ossil bodies ^^for no other end than to play the mimic 
m the mineral kingdom ; " — maintaining that figured 
stones were '^really the several bodies they represent, 
Or the mouldings of them petrified,'' and " not as some 
nave imagined, ^ a lusus nature/ sporting herself in 
the needless formation of useless beings/'-j- 




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Posth. Works, p. 327. 

t Posth. Works, Lecture, Feb. 15. 16S8, Hooke explained, 

^^ coiisiderable clearness, the difierent mpdes wherein organic 

^hstances may become lapidified ; and, among other illustrations, 

^ mentions some silicified palm-wood brought from Africa, on 

^ich M. de la Hire had read a memoir to the Royal Academy 

-trance (June, 1692), wherein he had pointed out, not only the 

^s ruimmg the length of the trunk, but the roots at one ex- 

y- De la Hire, says Hooke, also treated of certain trees 

petrified in " the river that passes by Bakan, in the king- 

^«j and which has for the space of ten leagues the virtue 

o Petrifying^ood." It is an interesting fact, that the silicified 

00 o e Irawadi should have attracted attention more than one 

hundred years ago. Remarkable discoveries have been recently 



VOL. I. 







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50 



HOOKE ON EARTHQUAKES. 



[Book L 



It was objected to Hookej 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 for 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- 
xnent, we find them/'f This doctrine, it is true, had 

r 

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 
Pr. 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. 1 689. f Posth. Works, p. 312. 








I 




-< 





Ch. III.] 



HOOKE'S DILUVIAL THEORY. 



51 



^nd other writers of antiquity, Hooke frequently re- 
^^s ; but the revival and development of the system 

^as an important step in the progress of modern 
science. 

Hooke enumerated all the examples known to him 
subterranean disturbance, from "the sad catastrophe 




of Sod 



om and Gomorrah " down to the Chilian earth- 



quake of 1646. The elevating of the bottom of the 

s^a, the sinking and submersion of the land, and most 

or the inequalities of the eai'th's surface, might, he 

^^d, be accounted for by the agency of these sub- 

^rranean causes: He mentions that the coast near 



Napl 



GS was raised during the eruption of Monte Nuovo ; 



^^«d that^b 1591, land rose in the island of St. Michael, 
uring an eruption ; and although it would be more 
>fficu!t, he says', to prove, he does not doubt but that 
^^^'e had been as many earthquakes in the parts of 

^^ earth under the ocean, as in the parts of the dry 
*^d; in confirmation of which, he mentions the im- 

"^^asurable depth of the sea near some volcanos. To 
test the extent of simultaneous subterranean 

, ^^ts, he refers to an earthquake in the West Indies, 
^ year 1690, where the space of earth raised, or 

"Struck upwards," by the shock, exceeded, he affirms, 

^he length of the Alps and the Pyrenees. 

■tiookes diluvial theory, — As Hooke declared the 



move- 



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favo 
bodi 



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hypothesis of the day, " that marine fossil 
les were to be referred to Noah's flood," to be 

^ iT !f ^^^^'^^^^^^ ^^ appears to have felt himself 
and 1 ^^"^"^ ^^ substitute a diluvial theory of his own, 

^us he became involved in countless difficulties 

and contradictions. " During the great catastrophe," 

e said, « there might have been a changing of that 

part which was before dry land into sea by sinking, 

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HOOKE— RAY. 



[Book I. 



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and of that which was sea into dry land by raising, and 
mai'ine 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 ijiwards, &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 

F 

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 naturahst, Ray, participated in the same desire 
to explain geological phenomena, by reference to causes 
less hypothetical than those usually resorted to.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 
mj^steries of nature he deservedly liongnv^d.^' ^^ On the Deluge , 

chap. iv. 



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Ch. HL] 



RAY, 



53 



natural history enabled him to elucidate the subject 

Earthquakes, he 



With 



various original observations. 



suggested, rhight 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. 
Ill 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, 
^e said, might have forced the subterranean waters 
<^utwards, as was, perhaps, indicated by " the breaking 
^P of the fountains of the great deep/' 
' Ray was one of the first of our writers who enlarged 
^pon 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 

+ 

<^ur system to its final dissolution ; and he wondered 
"^hy the eai^th did not proceed more rapidly towards a 
general 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 
o^^gin of our planet. His discourses, like those of 
■"ooke, are highly interesting, as attesting the familiar 
association in the minds of philosophers, in the age of 
ewton, of questions in physics and divinity. Ray 
gave 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 

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WOODWARD. 



[Book I, 



science 



Woodward. 



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 

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. 

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. Ill] 



BURNET. 



35 



% ■ 

to the order of their gravity, the heavier shells in stone, 
the lighter in chalk, and so of the rest."^ Ray im- 
niediately exposed the unfounded nature of this asser- 
tion, remarking truly, that fossil bodies ^^are often 
singled, heavy with light, in the same stratum ;" and 
l^e even went so far as to say, that Woodward "must 
have invented the phenomena for the sake of confirm- 



t 



a strong 



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Even Milton 



expression from the pen of a contemporary. 

Gurnet, 1690. — At the same time Burnet published 
his « Theory of the Earth." J The title is most cha- 
racteristic 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, 
ventured In his poem to indulge his imagination so 
ft'eely 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 
■w^aters were let loose from a supposed central abyss. 
Not satisfied with these themes, he derived from the 

I. 

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 
general conflagration, and proved that a new heaven 
and a new earth will rise out of a second chaos 
which will follow the blessed millennium. 

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

t Consequences of the Deluge, p. 165. 

t First published in Latin between the years 1680 and 1690. 

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6Q 



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 ordinary 
stamp. It was, in fact, a fine historical romance, as 
Buffon afterwards declared: but it was treated 
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 



as a 




1 

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ss 








ch. in.] 



WHISTON. 



57 



of Whiston, entitled, " A New Theory of the Earth ; 
therein the Creation of the World in Six Days, the 
Universal Deluge, and the General Conflagration, as 
^^id down in the Holy Scriptures, are shewn to be 
perfectly agreeable to Reason and Philosophy." He 
^as at first a follower of Burnet ; but his faith in the 
infallibility of that writer was shaken by the declared 
^pinion 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 
Gurnet's system^ though not original, for it was bor- 
J'owed from an Italian, Alessandro degli Alessandri, 
^ho 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 wheri Whiston first began his 
cosmological studies, and the principal novelty of his 
speculations consisted in attributing the deluge to the 

^^ar approach to the earth of one of these erratic 
l^odies. 

tins source, he adopted Woodward's theory, supposing 

^^1 stratified deposits to have resulted from the 

^ chaotic sediment of the flood." Whiston was one of 

he first who ventured to propose that the text of Ge- 

esis should be interpreted differd;ntly from its ordinary 

acceptation, so that the doctrine of the earth having 

istea long previous to the creation of man might no 

onger 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 

niost sober manner, and by the aid of mathematical 

j> 5 



Having ascribed an increase of the waters to 



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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 

'' Moses's Principia," wherein he ridiculed 



of his 



Woodward 



Celsius, 



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. 

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.)- 

ScJieuchzer, 1708. — In Germany, in the mean time, 
Scheuchzer laboured to prove, in a work entitled " The 

had 



(1708) 



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\ 



been remodelled at the deluge. Pluche, also, in 1732, 
wrote to the same effect; while HoJbach, in 1753, after 

r 

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



f 



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4 





m\ 



V* 



!. 



41 



2 





1 




Ch. III.] 



ITALIAN GEOLOGISTS— VALLISNERL 



59 



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

Italian Geologists — Vallisneri. 



I return with 



pleasure to the geologists of Italy, who preceded, as 
lias been already shown, the naturalists of other coun- 
^^^es in their investigations into the ancient history 
<^f the earth, and who still maintained a decided pre- 
eminence. They refuted and ridiculed the physico- 



W, 



Vallisneri f 



Whiston, and Wood 
comments on the 



of religion, as well as those of sound philosophy, had 
suffered by perpetually mixing up the sacred writings 
^ith questions in physical science. The works of this 
author were rich in original observations. He at- 
tenipted the first general sketch of the marine deposits 
<^f Italy, their geographical extent, and most charac- 

In his treatise " On the 



^eristic oriranlc remains 



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 

* R-amazzini even asserted, that the ideas of Burnet were mainly 
borrowed from a dialogue of one Patrizio j 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 critichej &:c. 1721. 

j> 6 




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60 



ITALIAN GEOLOGISTS — MORO. 



[Book I. 



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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 



t Matta 



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 

descendants of Japhet.t 



Mora 



Mo 



Ma 



Mountains § 



earthquakes, as expounded by Strabo, Pliny, and 
other ancient authors, with whom he was famihar, to 
the geological phenomena described by Vallisneri.|l 



-, ^j 



* Brocchi, p. 28. 



f Ibid. p. S3-. 



t Ibid, p. 37. 



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







^ 



_ \ 








LAZZARO MORO. 



61 



Ch. Ill] 

-^is attention was awakened to the elevating power of 
subterranean forces by a remarkable phenomenon 
which happened in his own time, and which had also 
peen noticed by Valllsneri in his letters. A new 
island rose in 1707 from a deep part of the sea 
^^ar Santorin in the Mediterranean, during continued 
snocks of an earthquake, and, increasing rapidly in 
Size, grew in less than a month to be half a mile in 
cii'cumference, and about twenty-five feet above high- 
'^ater mark. It was soon afterwards covered by vol- 
canic ejections, but, when first examined, it was found 
^^ be a white rock, bearing on its surface living oysters 
^^u Crustacea. In order to ridicule the various theories 
uen in vogue, Moro ingeniously supposes the arrival 
p^ this new island of a party of naturalists ignorant of 
rpn^r^f origin. One immediately points to the 



recent 



Marine shells, as proofs of the universal deluge ; another 
^gues that they demonstrate the former residence of 
^^ sea upon the mountains ; a third dismisses them 

^s mere sports of nature; while a fourth affirms, that 

^^y Were born and nourished within the rock in 

licient caverns, into which salt water had been raised 

the shape of vapour by the action of subterranean 
l^eat. 

Moro pointed with great judgment to the faults and 

^slocations of the strata described by Vallisneri, in 

Alps and other chains, in confirmation of his 

'^I'lne, that the continents had been heaved up by 





m 



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S 



if 



S so many of his views were in accordance with theirs, he 

^as 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 may presume that he 

did not read English. 




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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 
ascend through fissures. The sea gradually acquired 
saltness from volcanic exhalations, and, while it 
became more circumscribed in area, increased in 



to 



Its 



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. 



of Moro 



The style 



Moro 



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 GenereUi, 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, 



n 
1 



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Ch. Ill] 



LAZZARO MORO'S THEORY. 



63 







1 



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 
lail to be acceptable^ as illustrating the state of geology 
in Europe, and in Italy in particular, before the middle 
^f the last century. 

The bowels of the earth, says he, have carefully 
Pi'eserved 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 eifects of earthquakes in 
past times, which have changed vast spaces of sea into 
terra firma, and inhabited lands into seas. In this, 
^ore than in any other department of physics, are 
observations and experiments indispensable, and we 
J^ust 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 

r 

l^^arl, coal, pumice, gypsum, lime, and the rest. These 
ingredients are sometimes pure, and sometimes con- 
^usedly intermixed. Within are often imprisoned dif- 
^^rent marine fishes, like .dried mummies, and more 
frequently shells, Crustacea, corals, plants, &c., not 
only in Italy, but in France, Germany, England, Africa, 
■^sia, and America; — sometimes in the lowest, some- 
times in the loftiest beds of the earth, some upon the 
naountains, 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 
^^^1 ^^ ^^^^^ occur, as is sufficiently attested by 

silli. The remains of fossil ani- 



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64^ 



GENERELLI'S EXPOSITION OF 



[Book 1. 



mals consist chiefly of their more solid parts, and 
the most rocky strata must have been soft when 
such exuviae 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 



Marsill 



We 



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 



* Saggio fisico intorno alia Stoiia del Mare, part i. p. 24. 
: t '' Abbomino al sommo qualsivoglia sistema, che sia dl pfafita 
fabbricato in aria; massime quando ^ tale, che noii possa soste- 
nersi senza un miracolo," &c. — De' Crostacei e di altre Produz. 
del Mare, &c. 1749* 







-^ 



I 




Ch. III.] 



LA2ZAR0 MORO'S THEORY. 



65 




it\ V 



m. lit 




A brief abstract tben follows of Moro's tbeory, 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, 
Pi'esented itself to Hooke, half a century before, and 
forced him to resort to a former " crisis of nature :" 
^^t 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 
t^e mineral masses containing shells bore, upon the 
"^hole, but a small proportion to those rocks which 
^ere destitute of organic remains ; and the latter, says 
■the learned monk, might have been created as they 
^ow exist, in the beginning. 

Generelli then describes the continual waste of 
fountains 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 '^ 

" Senza violenze, senza finzioni, senza supposti, senza mira 
coll." De' Crostacei e di altre Produz. del Mare, &c, 1749. 






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66 



LAZZARO MORO'S THEORY. 



[Book I. 



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 diiFerent 
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. 



?J 



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 






« 




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Ch. 111.3 



MARSILLI. 



1 * 



67 



V r 

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 
ennploy 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 
"^any thousand times greater than at present, would 
^ave appeared preposterous and incredible, and would 
^ave required a hundred violent hypotheses ; but we 
^^e so unacquainted with the true sources of subter- 
ranean disturbances, that their former violence may in 
theory be multiphed indefinitely, without its being 
possible to prove the same manifest contradiction or 
absurdity in the conjecture. For this reason, perhaps, 
Moro preferred to derive the materials of the strata 
from volcanic ejections, rather than from transportation 
by running water. 

Marsilli Marsilli, whose work is alluded to by 

Generelli, had been prompted to institute inquiries 
mto 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 Siciiia. 



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68 . 



DONATI — BALDASSARI — BUFFO N. 



[Book I 



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



Donati 



But with a view of throw- 



ing further light upon these questions, Donati, in 1750, 
undertook a more extensive investigation of the Adri- 
atic, and discovered, by numerous 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 Area, 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. 

-BaZc?a55aW.— 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,— Buffbn 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 

1 "^ yr « 



cov 



ered. Mar 



formed horizontal strata, by washing away solid matter 







»fc^ 



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1 





Gh. 111.] 



BUFFOK 



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, 
hke Leibnitz and Moro, by the observations of Steno, 



^^ ne could not have imagined that the strata were 
generally horizontal, and that those v*^hich contain 
oi'ganic remains had never been disturbed since the era 

4 

^f their formation* He was conscious of the great 

r 

power annually exerted by rivers and marine currents 
^^ transporting earthy materials to lower levels, and he 
^^en contemplated the period when they would destroy . 
^n the present continents. Although in geology he 
^^s not an original observer, his genius enabled him to 
lender his hypothesis attractive ; and by the eloquence 
^^^h style, and the boldness of his speculations, he 
^^^akened curiosity, and provoked a spirit of inquiry 
amongst his countrymen. 

Soon after the publication of his " Natural History," 
^Inch was included his " Theory of the Earth," he 



m 



(d 



1751) 



^^e Sorbonne, or Faculty of Theology in Paris, inform- 

^S him that fourteen propositions in his works " were 

^^pi'ehensible, and contrary to the creed of the church/' 

he first of these obnoxious passages, and the only one 

^elatmg to geology, was as follows : — " The waters of 

^^ sea have produced the mountains and valleys of 

e land — , the waters of the heavens, reducing all to a' 

evel, will at last deliver the whole land over to the sea, 

the sea, successively prevailing over the land, will 

^ave dry new continents like those which we inhabit. 



99 



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



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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 1 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 hook respecting the formation of the earthy 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. 

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 



1- K- 



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Notwithstanding a want of 



«- 



Hist. Nat. torn. v. ^d. delTmp. Royale, Paris, 1769 






i'l 



-.-- - ■*» 



X- 







1 

1 




Ch.lii.] 



LEHMAN - GESNER. 



71 



currents. 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 

he bursting of the barriers of lakes, after the retreat 
the ocean. He also maintained that the elephants 

na other quadrupeds, so frequent in the lacustrine 

^nd^ alluvial deposits of Italy, had inhabited that 

peninsula ; and had not been transported thither, as 

some had conceived, by Hannibal or the Romans, nor 

y what they were pleased to term "a catastrophe of 
nature." 

Lehman, 1756. — In the year 1756 the treatise of 

^Uttian, a German mineralogist, and director of the 

. ^ssian mines, appeared, who also divided mountains 

^Q three classes: the first, those formed with the 

*^^ld, and prior to the' creation of animals, and which 

^ntained no fragments of other rocks; the second 

^^ss, those which resulted from the partial destruc- 

^n of the primary rocks by a general revolution ; and 

third class, resulting from local revolutions, and in 

P^J't from the Noachian deluge.* 

^ French translation of this work appeared in 1759, 
^ preface of which the translator displays very 
ightened views respecting the operations of earth- 
^^^' ^^ ^^11 as of the aqueous causes. 

ner^ 1758. — In this year Gesner, the botanist, 
nrich, published an excellent treatise on petrifac- 
3 and the changes of the earth which they testify .f 
^^ a detailed enumeration of the various classes of 
ssils of the animal and vegetable kingdoms, and re- 
arks on the different states in which they are found 
^ned, he considers the geological phenomena con- 



in th 



Ges 



^ 



E 



ssai d'une Hist. Nat. des Couches de la Terre, 1759. 



t John Gesner published at Leyden, in Latin. 




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72 



GESNER — ARDUINO. 



[Book I 



nected with them ; observing, that some, like those of 
CEningen, resembled the testacea, fish, and plants 
indigenous in the neighbom'ing 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 of shells, 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, Gerniany, and England are commented upon 
with fairness and discrimination. 

Arduinoy 1759. — In the year following, Arduinof , in 



* Part ii. chap, 9. 



t Giornale del Griselini, 1759. 



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Ch.Iiij 




MICHELL. 



73 



R 



j^s memoirs on the mountains of Padua, Vicenza, and 
erona, deduced, from original observations, the dis- 
inction 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 

Tohn Michell, Woodwardian Professor of Miner- 

^^%y at Cambridge, published, in the Philosophical 

^ansactions, an Essay on the Cause and Phenomena 

^ /Earthquakes.* ^ His attention had been drawn to 

this subject by the great earthquake of Lisbon in 1755. 

^ advanced many original and philosophical views 

^specting the propagation of subterranean movements, 

J^d the caverns and . fissures wherein steam might 

^ generated. In order to point out the application 

^^ his theory to the structure of the globe, he was led 

^ describe the arrangement and disturbance of the 

^^ta, their usual horizontality in low countries, and 

eir contortions and fractured state in the neighbour- 

^^d of mountain chains. He also explained, with 

^'pi'ising accuracy, the relations of the central ridges 

older rocks to the " long narrow slips of similar 

? stones, and minerals," which are parallel to 

ese ridges. In his generalizations, derived in great 

part from his own observations on the geological 

J S^^e a Sketch of the History of English Geology, by Dr. Fitton, 
^^^^' I^ev. Feb. 1818, re-edited Lond. andEdinb. Phil. Mag. 
^^ • I- and ii. 1832-33. Some of MichelFs Observations antici- 
in so remarkable a manner the theories established forty years 
. ^ards, that his writings would probably have formed an era 
^ *• ® science, if his researches had been uninterrupted. He held, 
^ wever, his professorship only eight years, when he succeeded to 
ne ce, and from that time he appears to have entirely discon- 
tinued his scientific pursuits. 



earth 



VOL. I. 



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CATCOTT — FORTIS — ODOARDI. 



[Book L 



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

Catcotty 1761. — Michell's papers were entirely free 
from all physico-theological disquisitions^ but some 

i 

of his contemporaries were still earnestly engaged in 



Woodwardian 



W 



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 

I 
* 

r 

Sui Corpi Marini del Feltrino, 1761. 



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THEORY OF RASPE. 



75 






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origin. He pointed out that the strata of these two 
groups were unconformable^ and must have been the 
deposits of different seas at distant periods of time. 

-S^^pe, 1763.— A history of the new islands by 
^^spe, an Hanoverian, appeared in 1763, in Latin.* 
^^ this work, all the authentic accounts of earthquakes 
^hich had produced permanent changes on the solid 
P^^ts of the earth were collected together and ex- 
^niined with judicious criticism. The best systems 
^hich had been proposed concerning the ancient 
history of the globe, boJ:h by ancient and modern 
^^ters, are reviewed ; and the merits and defects 

the doctrines of Hooke, Ray, Moro, Buffon, and 

^ '^ers, fairly estimated. Great admiration is expressed 

the hypothesis of Hooke, and his explanation 

the origin of the strata is shown to have been 

^ore correct than Moro's, while their theory of the 

*tects of earthquakes was the same, Raspe had not 

een MicheH's memoir, and his views concerning the 

geological structure of the earth were perhaps less 

^,^^rged ; yet he was able to add many additional 

. g^^ents in favour of Hooke's theory, and to render 

> ^s he said, a nearer approach to what Hooke would 

^ve written had he lived in later times. As to the 

P^iiods wherein all the earthquakes happened, to which 

Owe the elevation of various parts of our continents 

islands, Raspe says he pretends not to assign their 

ion, still less to defend Hooke's suggestion, that 

^ convulsions almost all took place during the deluge 

oah. He adverts to the apparent indications of 



4IF 



Amst. et Leip^igt 



of th ^^^^^ ^ ^^^^ ^^^^^ Insulk. Raspe was also the editor 
176 -*' ^^^^^^sophical Works of Leibnitz. 

^^ 5- ' also author of " Tassie's Gems," and " Baron Mun- 
chausen's Travels." 

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FUCHSEL. 



[Book L 



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 an eloquent exhortation to na- 
turalists to 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. 

Fuchsely 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.-j- 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 

# ActaAcadeniise Electoralis Maguntmas, vol. li. Erfurt. 
+ This accoiMit of Fuchsel is derived from an excellent analysis 
of his memoirs by M. Keferstein. Journ. de G^ologie, torn. ii. 



Oct. tss 









1 

1 



Ch. IIL] 



FUCHSEL — ERANDER. 



77 



or the marine strata called in Germany " muschel- 
l^alk," at the same time that the terrestrial plants of 
wiany 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 groundo 

As there were plants and animals in the ancient 
periods, so also there must have been men, but they 
^id not all descend from one pair, but were created at 
■Various points on the earth's surface ; and the number 
^i these distinct birth-places was as great as are the 
Anginal 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 ; 
^nd although some of his speculations were fanciful, 
^^s views coincide much more nearly with those now 
generally adopted, than the theories afterwards pro- 
'Mulgated by Werner and his followers. 

Grander ^ 1766. — Gustavus Brander published, in 
t766, his " Fossilia Hantoniensia,^' containing excellent 

gures of fossil shells frx3m the more modern marine 
strata of our island. '* Various opinions," he says in 
the preface, "had been entertained concerning the 
i^e when and how these bodies became deposited, 
^ome there are who conceive that it might have been 
effected in a wonderful length of time by a gradual 



chan 



sea 



5? 



common cause assigned is that of "the deluge 



&c. But the most 

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78 



SOLDANl — 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- 
Soldaniy 1780, — Soldani applied successfully his 
knowledge of zoology to illustrate the history of stra- 

4 

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 — Testay 1793. — A lively controversy arose 
between Fortis and another Italian naturalist, Testa, 



Mon 



Their 



t 



that they were aware that a large proportion of the 
Subapennine shells were identical wuth 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 region.s 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, t 



ks. 



* Saggio orittografico, &c. 1780, and other Wor 

f Lett, sui Pesci Fossili di Bolca. Milan, 1793. 

I This argument of Testa has been strengthened of late years 



^ 



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_ , _^ 



Ch. III.] 



WHITEHURST— PALLAS — SAUSSURE. 



79 



i 



1 



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Cort 



Wh 



esi — Spallanzani — Wallerius — Whitehurst 



^i^d 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 
taking, in the same country, in investigating the 



ancient and modern volcanic rocks, some of the most 
^^iginal observers among the Eng:lish and German 



inters, Whitehurst ^^ and Walle 



were wasting 



their strength in contending, according to the old 
^oodwardian 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 



^^gkteenth 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 
^hose labours contributed to this end. After an at- 
tentive examination of the two great mountain chains 

\ 

. _ . _ — 11 Ill ^ ■ 

"y the discovery, that dealers in shells had long been in the habit 
01 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 within 
^ight fathoms of the surface, that the temperature of the Medi- 
terranean is on an average S^^ of Fahrenheit higher than the 
^'estcrn 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. 

Inquiry into the Original State and Formation of the Earth. 



1778. 



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80 



PALLAS— SAUSSURE. 



[Book 1. 



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 



cks.* 



In his "Travels in Russia," in 1793 and 1794, he 
many geological observations on the recent 



made 



Wol 



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 geoloo-y. 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- 



t 



I 



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. 

F 

* Observ. on the Formation of Mountains. Act. Petrop. anq. 
1778, parti, 
f Nov. comm. Petr. XVII. Cuvier, Eloge de Pallas. 



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-y^^_~ 



81 



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 
Button'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 
Science in France — Growing Importance of the Study of 

Organic Remains, 

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



Proirress of the 



We 



Mines 



directed his attention not merely to the composition 
^nd external characters of minerals, but also to what 
^e 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 
'W'asted, in mining adventures, has been well exposed by an emi- 
nent practical miner. — See " Prospectus of a School of Mines m 
Cornwall, by J, Taylor, 1825." 









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82 



WERNER. 



[Book T, 



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 wanderino- 
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 i 



lead 



m buildin<x 



ferent ages and nations ; and the physical geography 
of a country frequently invited him to treat of military 
tactics. The charm of his manners and his eloquence 
-kindled enthusiasm in the minds of his pupils ; 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. 




^ 





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H* 



i 



Ch. IV.] 



WERNER. 



8^ 



before unheard of in Europe, was raised to the rank 
^f 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 writinc^, 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 
bis 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 from his 
exertions. If it be true that delivery be the first, 
Second, and third requisite in a popular orator, it is no 
^ess certain that to travel is of first, second, and third 
iniportance 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 
niodel of his own province. It became a ruling object 
of ambition in the minds of his pupils to confirm the 

* Cuvier, Eloge de Werner. 




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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 
greywacke slate, containing organic remains, have re- 
cently been found entangled in the granite of the 



M 



* 



The principal 



Werner 



system of in- 



/ 



structlon 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 

; ■ __ 

* lam 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. 






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Ch. IV.] 



VULCANISTS AND NEPTUNISTS. 



85 



British strata by our countryman, William Smith, to 
Wiose 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 
^ith the levels of existing valleys, like many in Au- 
^^^gne and the Vivarais. These basalts, and all other 
^ocks 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 
Apposed, in a twofold sense, to the doctrine of the per- 
manent agency of the same causes in nature ; for not 
^^V did he introduce, without scruple, many imaginary 
^^nses supposed to have once effected great revolutions 
m 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. 

^0 earlv as J 768, before Werner had commenced 
ms mineralogical studies, Raspe had truly charac- 
^^erized the basalts of Hesse as of igneous 
"^^duino, as we have already seen, had pointed out nu- 
merous varieties of trap-rock in the Vicentin as ana- 



origm. 



log 



ous to volcanic products, and as distinctly referable 



to ancient submarine eruptions. Desmarest, as before 
stated, had, in company with Fortis, examined the 



Vi 



centm in 1766, and confirmed Arduino's views. In 



1772, Banks, Solander, and Troil, compared the co- 
lumnar basalt of Hecla with that of the Hefcirides, 



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86 



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 
scoriae, and bearing the closest analogy to rocks in 
ether parts of Europe, the igneous origin of which was 
denied by the school of Freyberg. -I- 

* Cuvier, Eloge de Desmarest, 

t Journ. de Phys. vol. xiii. p. 115. ; and M^m. de I'lnst., 

Sciences Mathemat. et Phys. vol.vi. p. 219. 



/ 



i 








I 



I 



I 



^^h. IV.] 



DOLOMIEU -, MONTLOSIER. 



87 



D 



esmarest's map of Auvergne was a work of uncom- 
i^on merit. He first made a trigonometrical survey 
or the district, and delineated its physical geography 
'^^th 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, 
^^he different ages, and sometimes even the structure, 
^^ the volcanic rocks, distinguishing them from the 

^esh"Water and the granitic. They alone who have 
^Q^i'efully studied Auvergne, and traced the different 

^va-streams from their craters to their termination, 
the various isolated basaltic cappings, — the rela- 
tion of some lavas to the present valleys, — the ab- 



^^nce of such relations in others, 



can appreciate the 



fWer 



extraordinary fidelity of this elaborate work. No other 
^^strict of equal dimensions in Europe exhibits, per- 
^^ps, so beautiful and varied a series of phenomena ; 
^^d, fortunately, Desmarest possessed at once the 
^^thematical knowledge required for the construction 
^^ ^ >^ap, skill in mineralogy, and a power of original 
generalization. 

J^olomieu — Montlosier. 
^er s contemporaries, had found prismatic basalt among 
^ ancient lavas of Etna; and, in 1784, had observed 
^ e alternations of submarine lavas and calcareous strata 
'^^ the Val di Noto, in Sicily.* In 1790, also, he de- 
^^^bed similar phenomena in the Vicentin and in the 
yrolt Montlosier published, in 1788, an essay on 
e theory of the volcanos of Auvergne, combining ae- 
rate local observations with comprehensive views, 
^twithstanding this mass of evidence, the scholars of 

L I 

\ 

Journ. de Phys. torn. xxv. p. 191. 
t lb, torn, xxxvii. partii. p. 200.' 



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88 



HUTTON, 



[Book I 



** ^ 



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, 

Huttorij 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, 



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* Cuvier, Eloge de Desmarest 



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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 
^'esided 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 
niade frequent tours through different parts of England 
^nd Scotland, acquiring considerable skill as a 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 
^' length he had matured his views, he published, in 
1^788, his <« Theory of the Earth V and the same, 
afterwards more fully developed in a separate work, in 
1^795. This treatise was the first in which geology was 
declared to be in no way concerned about " questions 
^^ to the origin of things;" the first in which an 
attempt was made to dispense entirely with all hypo- 
tl^etical causes, and to explain the former changes of 
tl^e earth's crust by reference exclusively to natural 
Agents. Hutton laboured to give fixed principles to 
geology, as Newton had succeeded in doing to astro- 
^ovay: but, in the former science, too little progress 
^^d 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 



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SO 



HUTTONIAN THEORY. 



[Book T^ 



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, 



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Ch. IV.3 



HUTTONIAN THEORY. 



91 



I 



m 1*785, the most clear and unequivocal proofs in sup- 
port of his views. Veins of red granite are there seen 
orancliing out from the principal mass, and traversing 
the black micaceous schist and primary limestone. 



Th 



^ intersected stratified rocks are so distinct in 



or 



colour and appearance as to render the example in 
that locality most strikins;, and the alteration of the 
iiniestone 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 
foi'th such marks of joy and exultation, that the guides 
^ho accompanied him, says his biographer, were con- 
vinced that he must have discovered a vein of silver 
gold. * He was aware that the same theory would 
^^t explain the origin of the primary schists, but 
these he called primary, rejecting the term primitive, 
^nd Was disposed to consider them as sedimentary 
^ocks altered by heat, and that they originated in 
some other form from the waste of previously existing 
^ocks. 

% this important discovery of granite veins, to 
^hich he had been led by fair induction from an inde^ 
Pendent class of facts, Hutton prepared the way for 
^^^ 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 
nave been formed before the creation of living beings. 
Moro, 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 dobe. The same tenet was an article 



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



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92 



HUTTONIAN THEORY. 



[Book I 



oi 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- 
xacters 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 subhmity 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. 



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Ch. IV.] 



HUTTONIAN THEORY. 



93 



J- he characteristic feature of the Huttonian theory 
^^s^as before hinted, the exclusion of all causes not 
si^pposed to belong to the present order of nature. 
•*^^t Hutton had made no step beyond Hooke, Moro, 
^^d Raspe, in pointing out in what manner the laws 

governing subterranean movements might bring 



now 



He imagined that 



the 



terials 



about geological changes, if sufficient time be allowed. 
^n 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 
^a-rth's crust to subsidence. 
Continents were first gradually destroyed by aqueous 
^ep^radation ; and when their ruins had furnished ma- 

for new continents, they were upheaved by 

^o'ent convulsions. He therefore required alternate 

P^nods of general disturbance and repose ; and such 

^^ believed had been, and would for ever be, the 

^^^rse of nature. 

^cnerelli, in his exposition of Moro's system, had 
^^de a far nearer approximation towards reconciling 
geological appearances with the state of nature as 
own to us ; for while he agreed with Hutton, that 



kn 

^^^ decay and reproduction of rocks were always in 
progress, proceeding with the utmost uniformity, the 
earned Carmelite represented the repairs of moun- 
ting by elevation from below to be effected by an 
Equally constant and synchronous operation. Neither 
^* these theories, considered singly, satisfies all the 
conditions of the great problem, which a geologist^ 
^^0 rejects cosmological causes, is called upon to 
Solve ; but they probably contain together the germs 
^i 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 






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PLAYFAIR'S ILLUSTRATIONS OF HUTTON. £Book I- 






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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, 

* Play f air s illustrations of Hutton. — The explanation 
proposed by Hutton and by Playfair, the illustrator of 
his theory, respecting the origin of valleys, and oi 
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 
visionaiy 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- 




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^h.iv.] 



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PLAYFAIR-S ILLUSTRATIONS OF HUTTON. 



95 



^n the biography of his friend, has the following 
comment on this part of their theory: — " In the pla- 
netary motions, where geometry has carried the eye 
so far, both into the future and the past, we discover 
^0 mark either of the commencement or termination 
Qt the present order. It is unreasonable, indeed, to 
^^Ppose that such marks should any where exist. The 
Author of Nature has not given laws to the universe, 
^'nich, like the institutions of men, carry in themselves 



th 



^ elements of their own destruction. He has not 



P^i'mitted in His works any symptom of infancy or of 
*^^d age^ or any sign by which we may estimate either 
*^heir future or their past duration. He ma^ put an 
^^d^ as he 710 doubt gave a beginning^ to the present 
vStem, at some determinate period of time ; but we 
^^y rest assured that this great catastrophe will not be 
^^ought about by the laws now existing, and that it is 



th 



^^t 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 

}^ I'eader, unless he recalls to his recollection that 
^ niind of the English public was at that time in a 

tate of feverish excitement. A class of writers in 

^ance had been labouring industriously, for many 
years, to diminish the influence of the clergy, by 

^Pping the foundations of the Christian faith ; and 
^^ir success, and the consequences of the Revolution, 

^d alarmed the most resolute minds, while the iraa- 

Sanation of the more timid was continually haunted by 

^ead of innovation, as by the phantom of some fearful 
dr 



earn. 



* Playfair's Works, vol. iv. p. 55. 



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96 



VOLTAIRE. 



[Book I. 



J 

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 

F 

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 eK- 
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 

4 

^ * In allusion to the theories of Burnet, Woodward, and other 
physko.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 envoy^e a 1' Aca- 
demic de Boulogne, sur les Changemens arrives dansnotre Globe. 
Unfortunately, this and similar ridicule directed against the cos- 
moo-onists was too well deserved. 



f See the chapter on " Des Pierres figure's. 



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3%| 



Ch. IV.] 



VOLTAIRE. 



97 



Mountains 



He would 



sometimes, in defiance of all consistency, shift his 
ground when addressing the vulgar ; and, admitting 
the true nature of the shells collected in the Alps 
^^d other places, pretend that they were Eastern 
species, which had fallen from the hats of pilgrims 
coming from Syria. The numerous essays written by 



him 



on geological subjects were all calculated to 



lu 



strengthen prejudices, partly because he was ignorant 
^f the real state of the science, and partly from his 
had faith.f On the other hand, they who knew that 
his attacks were directed by a desire to invalidate 
^cripture^ and who were unacquainted with the true 
Merits of the question, might well deem the old di- 

vian 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 
geology. First, we find many able naturalists ad- 
ducing the fossil remains of marine animals as proofs 
^f 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 
otean." In another place also, when speaking of the fossil shells 
^* Touraine, he admits' their true origin. 

t As an instance of his desire to throw doubt indiscriminately on 
^^1 geological data, we may recall the passage where he says, that 

the bones of a rein-deer and hippopotamus discovered near 
^tampes 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. 




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98 



SPIRIT OF INTOLERANCE. 



tBook I 



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 



Williams 



who published a " Natural 



Min 



* The Task, book iii. « The Garden." 




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Ch. IV.] - KIRWAK-DE LUC. " 99 

L ■ 

Kingdom," in 1789; a work of great merit for that 
^^y> and of practical utility, as containing the best 
Q^ccount 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 



<^olours and structure ; and also with " warping every 
thing to support the eternity of the world."* He 
descants on the pernicious influence of such sceptical 
Motions, as leading to downright infidelity and atheism, 
'^ and as being nothing less than to depose the 
Almighty Creator of the universe from his office," f 

Kirwan—DeLuc. — Kirwan, president of the Royal 
Academy of Dublin, a chemist and mineralogist of 
Some merit, but who possessed much greater authority 
^^ the scientific world than he was entitled by his 
*^alents to enjoy, said, in the introduction to his "Geo- 
^^gical Essays, 1799," '^ thdA 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 
^*^arcely surpassed by Burnet and Whiston, in his 
desire to adduce the Mosaic writings in confirmation 
^f his opinions. 

De Luc, in the preliminary discourse to his Treatise 
^^ Geology §, says, "the weapons have been changed 
"y 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 
tailure of former geological systems to their having 
been antl-Mosaical, and directed against a " sublime 

These and similar imputations, reiterated 



tradition." 



* P. 577. 

\ Introd. p. 2. 



t P. 59. 

§ London, 1809. 



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100 



SPIRIT OF INTOLERANCR 



[Book T. 



to 



in the works of De Luc, seem to have been taken for 

I L 

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- 
vaHdate scriptural tenets. On the contrary, the 
majority of them who were fortunate enough " 
discover the true causes of things," rarely deserved 
another part of the poet's panegyric, '^Atque metiis 

f 

omnes subjecit pedihusr 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.* 






ii' 




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♦ ■M 



* In a most able article, by Mr. Drinkwater, on the " Life of 
Galileo/' published in the " Library of Useful Knowledo-e " 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- 



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PLAYFAIR'S DEFENCE OF HUTTON. 



101 



I 



Ch. IV.] 

Hutton answered Kirwan's attacks with great 
warmth, and with the indignation justly excited by 
unmerited reproach. "He had always displayed," 
^^ys Playfair, " the utmost disposition to admire the 
beneficent design manifested in the structure of the 
World ; and he contemplated with delight those parts 
^f his theory which made the greatest additions to our 
knowledge of final causes." We may say with equal 
^^^th, that in no scientific works in our language can 
^ore eloquent passages be found, concerning the fit- 
^^ss, harmony, and grandeur of all parts of the creation, 
*^han in those of Playfair. They are evidently the un- 
affected expressions of a mind, which contemplated 

e study of nature, as best calculated to elevate our 



th 



Conceptions of the attributes of the First Cause. At 
^^y other time the force and elegance of Playfair's 
^tyle must have insured popularity to the Huttonian 
doctrines; but, by a singular coincidence, Neptuni- 
^^^ism and orthodoxy were now associated in the same 
c^eed; 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. 
l^hese fictions the Saxon professor had borrowed with 
httle modification^ and without any improvement, from 
*^is predecessors. They had not the smallest foun- 
dation either in Scripture or in common sense, and 
^^Te 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. 

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102 



SMITHES MAP OF ENGLAKD. 



[Book I. 



According to De Luc, the first essential distinction 
to be made between the various phenon^ena 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 saidj 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 File. 




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Ch. IV 1 



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 
"lap of the whole of England ; and, with the greatest 
disinterestedness of mind, communicated the results of 
liis 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 
"•ace. 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 
<iivisions the whole complicated series of British rocks. 
I^'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 
^he 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 
in every country in Europe. Smith adopted for the 
"lost 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. 



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104 



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. 



/ 



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- 





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Whewell, British Cntic, No. xvii. p. 187. 183L 

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Ch. IV.] 



ST13DY OF ORGANIC REMAINS. 



105 



gaged in furnishing materials for future generalizations. 
-By acting up to these principles with consistency, they 
^n a few years disarmed all prejudice, and rescued the 
science from the imputation of being a dangerous, or 
^t 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, 
^here 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 
■^ork of Cuvier and Brongniart, published in 1808, 



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the Neighbourhood of Paris." 



We 



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- 





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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 
eonsideration 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 



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* Book iv. chap. ii. 



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Ch. IV.] 



MODERN PROGRESS OF GEOLOGY. 



107 



sedimentary matter, and the slow development of 
wganic life. If many writers, and Cuvier himself in 
the number, still continued to maintain, that "the 
thread of induction was broken*," yet, in reasoning 
% the strict rules of induction from recent to fossil 
species, they in a great measure disclaimed the dogma 
^hich in theory they professed. The adoption of the 
same generic, and, in some cases, even of the same 
specific, names for the exuviae 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 

The growing importance, then, of the 



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guage 



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 
^aily 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, 
^ith 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 





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108 



MODERN PROGRESS OP GEOLOGY, 



tBook I. 



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 mad 
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 



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Ch. IV.] 



MODERN PROGRESS OF GEOLOGY. 



109 



yet imperfect, and they who comfe after us may be 
expected to reap the most valuable fruits of our labour. 
Meanwhile the charm of first discovery is our own ; 
^^d, as we explore this magnificent field of inquiry, 
l^e 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 
^ bliss like that of creating." * 



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Niebuhr's Hist, of Rome, vol. i. p. 5. Hare and Thirlwall's 



translation. 




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CHAPTER V. 



CAUSES WHICH HAVE RETARDED THE PROGRESS OF 



GEOLOGY. 



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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.). 



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If 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 






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Ch. v.] 



PROGRESS OF GEOLOGY, 



111 



tbe 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 
^^i^e assemblage of general causes, they conceive, 
^ay have been sufficient to produce, by their various 
combinations, the endless diversity of effects, of which 
*^e shell of the earth has preserved the memorials ; 
^nd, consistently with these principles, the recurrence 
^f analogous changes is expected by them in time to 
come. 

Whether we coincide or not in this doctrine, we must 
^dtnit that the gradual progress of opinion concerning 
^he 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. 
^^ an early stage of advancement, when a great num- 
ber of natural appearances are unintelligible, an eclipse^ 
^^ earthquake, a flood, or the approach of a comet, 
^^th many other occurrences afterwards found to be- 
^^^S 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- 
^"^aterial 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 
^"'J'egular 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 




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112 



PREJUDICES "WHICH RETARD 



[Book t 



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 
time. — 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 

r 

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 niay 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, tliat the earth was never the abode of living 



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THE PROGRESS OF GEOLOGY. 



113 



Ch. v.] 

beings until the creation of the present continents, 
and of the species now existing, — it is easy to perceive 
^hat extravagant systems they would frame, while 
under the influence of this delusion, to account for the 
nionuments discovered in Egypt. The sight of the py- 
ramids, obelisks, colossal statues, and ruined temples, 
^ould 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 
^t first to refer the construction of such stupendous 
^orks to some superhuman powers of a primeval world. 
■^ 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 
fij'st monarch, reigned nine thousand years; after 
^hom came Hercules and other demigods, who were 
^t last succeeded by human kings. 

When some fanciful speculations of this kind had 
^niused their imaginations for a time, some vast repo- 
sitory of mummies would be discovered, and would 
ittimediately undeceive those antiquaries who enjoyed 
^^ opportunity of personally examining them; but the 
P^'ejudices of others at a distance, who were not eye- 
witnesses of the whole phenomena, would not be so 
easily overcome. The concmTent 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 
niodify and defend their old positions. Each new 
i^^vention would violate a greater number of known 



.1 



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to 



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- 
ineters 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 tliey 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 fplly 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 Virgil's Elysium — the archetypes of men not yet 
called into existence?" 

These speculations, if advocated by efoquent 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 natnrp. and 







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Ch. v.] 



THE PROGRESS OF GEOLOGY. 



115 



not of art. But when one generation had passed 
^^ay, 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 to the 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 
tile 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 
^iews concerning the state of things in former ages, 
^ay be conceived by supposing the annals of the civil 
and military transactions of a great nation to be 



of one hundred instead of two thousand 



perused under the impression that they occurred in 

^ period 

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 



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116 



PREJUDICES WHICH RETARD 



[Book I 



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 
msurmountable 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 










Il 



A 




I 



I 



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 



^ay raise the coast of Chili for a hundred miles to the 
average height of about three feet. A repetition of two 
t^^ousand shocks, of equal violence, might produce a 
fountain-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 
^ith the order of events experienced by the Chilians 
from the earliest times ; but if the whole of them were 
^0 occur in the next hundred years, the entire district 
^ust be depopulated, scarcely any animals or plants 
could survive, and the surface would be one confused 
^cap 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 
^^c so unusual, that it would be inconsistent with all 
calculation of chances to suppose them to happen at 
^^0 and the same time. When the unlooked-for asso- 
ciation of such rare phenomena is witnessed in the 
Present course of nature, it scarcely ever fails to excite 
^ suspicion of the preternatural in those minds which 
^^G not firmly convinced of the uniform agency . of 
^ccondary causes; — as if the death of some individual 
^^ whose fate they are interested happens to be ac- 
companied by the appearance of a luminous meteor, 
ci" a comet, or the shock of an earthquake. It would 
"^c 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 



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118 



PREJUDICES WHICH RETARD 



[Book I 



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rare and unconnected in their nature, which were 
imagined by the Woodwardian hj^-phothesis 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 mmd 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. 



J 

I 



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V 



i 



Ch. v.] 



THE PROGRESS OF GEOLOGY. 



119 



youn 



ger 



and all the luxuriance of animal and vegetable forms 
or which Nature is so prodigal in those regions. The 
^ost reasonable supposition, perhaps, which he could 
^ake, if by the necromancer's art he was placed in 
®^ch a situation, would be, that he was dreaming; 
^^d if a geologist form theories under a similar delu- 
siOHj vire cannot expect him to preserve more con- 
sistency in his speculations, than in the train of ideas 
^^ an ordinary dream. 

It may afford, perhaps, a more lively illustration of 
^^e principle here insisted upon, if I recall to the 
header's recollection the legend of the Seven Sleepers- 
Xhe scene of that popular fable was placed in the two 
*^enturies which elapsed between the reign of the 
^^peror Decius and the death of Theodosius the 

In that interval of time (between the years 
^4^9 and 450 of our era) the union of the Roman 
empire had been dissolved, and some of its fairest pro- 
^^^ces overrun by the barbarians of the north. The 
^^at of government had passed from Rome to Con- 
^^^ntinople, and the throne from a Pagan persecutor 
^ a succession of Christian and orthodox princes. 
^iie genius of the empire had been humbled in the 
^^st, and the altars of Diana and Hercules were on 
e 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 
^G side of an adjacent mountain, where they were 
doomed to perish by the tyrant, who gave orders that 
e entrance should be firmly secured with a pile 
ef 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 



* 



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* Gibbon, Decline and Fall, chap, xxiii. 



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:l M \ii 



Ch. v.] 



THE PROGRESS OF GEOLOGY. 



121 



iniperceptibly advance from youth to age, without ob- 
serving the gradual, but incessant, change of human 
^"airs ; 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. 
•^^t if the interval between two memorable eras could 
"^ 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- 
twined a lively and recent impression of the old, his 
^^^prise and his reflections would furnish the pleasing 
^^bject of a philosophical romance,"* 

PT^udices arising from our peculiar position as in - 
^bitants of theland. — The sources of prejudice hitherto 
Considered may be deemed peculiar for the most part 
*'^ the infancy of the science, but others are common 
to the first cultivators of geology and to ourselves, and 
^^^ all singularly calculated to produce the same de- 
ception, and to strengthen our belief that the course of 
Mature in the earlier ages differed widely from that now 
established. Although these circumstances cannot be 

y explained without assuming some things as 
Proved, which it will be the object of another part of 
lis Work to demonstrate, it may be well to allude to 
hetn briefly in this place. 

-the first and greatest difficulty, then, consists in 



full 



^^ habitual 
obs 



unconsciousness that our position as 



ci'vers is essentially 
^cavour 
nowi 



unfavourable, when we on- 



to estimate the magnitude of the changes 
in progress. In consequence of our inattention to 
^s subject, we are liable to serious mistakes in con- 
as tmg the present with former states of the globe. 



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Gibbon, Decline and Fall, chap, xxiii 



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122 



PREJUDICES WHICH RETARD 



[Book I 



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.— ^OY 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 









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^ 



Ch. v.] 



THE PROGRESS OF GEOLOGY. 



123 



earth's history requires no ordinary share of discretion ; 
tor We are precluded from collating the corresponding 
parts of the system of things as it exists now, and as 
^^ existed at former periods. If we were inhabitants 
^t 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 
^^^e other hand^ there can be little doubt, although the 
deader 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 
behold, on the one hand, the decomposition of rocks in 
^'^e atmosphere, or the transportation of matter by 
Running water ; and, on the other, examine the depo- 
sition of sediment in the sea, and the imbedding of 

^liimal 



and vegetable 



remains in new strata. He 



^*§l^t ascertain, by direct observation, the action of a 

fountain torrent, as well as of a marine current ; might 

Compare the products of volcanos poured out upon the 

^^d with those ejected beneath the waters ; and 

^^ghtmark, on the one hand, the growth of the forest, 

^^d on the other that of the coral reef. Yet, even 

^th these advantages, he would be liable to fall into 

^ greatest errors when endeavouring to reason on 

*^cks of subterranean origin. He would seek in vain, 

ithin the sphere of his observation, for any direct 

alogy 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." 

4 

, iiut if we may be allowed so far to indulge the 
imagination, as to suppose a being entirely confined to 



^^e nether world 



some " dusky melancholy sprite 



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124 



PREJUDICES WHICH RETARD 



[Book I 



Of 



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. * 
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 ail 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 



I 



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-♦ 









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. 



<^. V.3 



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 
^ass. The tenets of the schools of the nether and of 
'^he upper world would be directly opposed to each 
other, for both would partake of the prejudices in- 
evitably resulting from the continual contemplation of 
^^^ class of phenomena to the exclusion of another. 
-*Ian observes the annual decomposition of crystalline 
and igneous rocks, and may sometimes see their con- 
^e^sion into stratified deposits ; but he cannot witness 
*|^e reconversion of the sedimentary into the crystal- 
line by subterranean fire. He is in the habit of re- 
garding all the sedimentary rocks as more recent than 
^he unstratified, for the same reason that we may sup- 
pose him to fall into the opposite ei'ror if he saw the 
^^igin of the igneous class only. 



Assumption of the discordance of the ancient 
-A^D existing causes of change unphiloso- 

^HICAL. 

^t is only by becoming sensible of our natural dis- 
^wantages that we shall be roused to exertion, and 
Prompted to seek out opportunities of observing such 
^t the operations now in progress, as do not present 
^etnselves readily to view. We are called upon, in 
^^^ i'esearches into the state of the earth, as in our 
^J^deavours to comprehend the mechanism of the 
leavens, to invent means for overcoming the limited 
ange of our vision. We are perpetually required to 
^l^gy as far as possible, within the sphere of observ- 
ation, things to which the eye, unassisted by art; could 
^ever obtain access. 

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126 



ASSUMED DISCORDAKCE OF 



[Book I 



i 



r 

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 

L 

L 

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 

r 

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, 
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 
bad 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 science? 

r 



There is nothing ana- 






I 



n _ 

I 



I r 



\ 






<Ch. V.3 



ANCIENT AND MODERN CAUSES. 



127 



^ould not dissipate the delusion, for the whole burden 
or proof would now be thrown on those who insisted 
on the stability of the system from a remote period, 
^nd 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 
*o the advancement of astronomy; for, instead of per- 
severing in the attempt to improve their instruments, 
^nd laboriously to make and record observations, the 
greater number would despair of verifying the conti- 
nued existence of the heavenly bodies not visible to 
^^e naked eye. Instead of confessing the extent of 
tlieir ignorance, and striving to remove it by bringing 
^0 light new facts,, they would indulge in the more 
^asy and indolent employment of framing imaginary 
theories concerning catastrophes and mighty revolu- 
"^lons in the system of the universe. 

For more than two centuries the shelly strata of the 
^nbapennine hills afforded matter of speculation to the 
early geologists of Italy, and few of them had any 
^nspicion that similar deposits were then forming in 
the neighbouring sea. They were as unconscious of 
^he 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 
giving and reflecting light, and performing their move- 
•*^ents as of old. Some imagined that the strata, so 
^ich in organic remains, instead of being due to second- 
9.ry agents, had been so created in the beginning of 
things by the fiat of the Almighty ; and others ascribed 
t^ie imbedded fossil bodies to some plastic power 
^hich resided in the earth in the early ages of the 
^orld. At length Donati explored the bed of the 

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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 geometers 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- 



^ 







> II 






1 




V 



Ch. v.] 



ANCIBKT AND MODERN CAUSES. 



129 



r 

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. 
^ut, after repeated experience of the failure of 
attempts to speculate on different classes of geological 
plienomena, as belonging to a distinct order of thmgs, 
^ach new sect persevered systematically in the prm- 
ciples adopted by their predecessors. They invariably 
began, as each new problem presented itself, whether 
^elating to the animate or inanimate world, to assume 
^^ 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 
^alleys, 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 




always with the feeling. 



that they conceded what they were justified a priori 
in deeming improbable. In a word, the same men 
^ho, 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 




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141 



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130 



ASSUMED BISCORDANCE OF 



[Book I 



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 hi& 
curiosity cannot fail to be excited by having his atten- 

r 

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 
tlie 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 



1' 




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th. v.] 



AKCIENT AND MODERN CAUSES. 



131 



formed by slow and insensible degrees in a great lapse 
^f ages : yet, until organic remains were minutely 
examined and specifically determined, it was rarely 
possible to prove that the series of deposits met with 
in one country was not formed simultaneously with 
^^at 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 



origm. 



but formed in succession. We 



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- 
nent, 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. 
gist, whose observations have been confined to England, 
^s accustomed to consider the superior and newer 
groups of marine strata in our island as modern, — and 
such they are, comparatively speaking ; but when he 
^^as travelled through the Italian peninsula and Sicily, 
^nd has seen strata of more recent origin forming 
n^om^tains several thousand feet high, and has marked 
a long series both of volcanic and submarine operations, 
^11 newer than any of the regular strata which enter 
largely into the physical structure of Great Britain, he 



A geolo- 




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* See Book iv. chap. lii 

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132 



ASSUMED DISCORDANCE OF 



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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 eff-ects 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. 

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







1 



4! If 



■--^ 









, 






Ch. v.] 



ANCIENT AND MODERN CAUSES. 



133 



to imagine that one district was not at 



eruptions as invalidated ; and there was the greatest 
inconsistency 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 
^t any former epoch parsimonious of time and prodigal 

^f violence 

rest, while another was convulsed — that the disturb- 
^^g forces were not kept under subjection, so as never 
^0 carry simultaneous havoc and desolation over the 
^l^ole earth, or even over one great region. If it 
^^uld have been shown, that a certain combination of 
^^rcumstances 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 
^ot 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 
^gain in past times. The existence of enormous seas 
^f fresh water, such as the North American lakes, the 
surface of the largest of which is elevated more than 
^^x hundred feet above the level of the ocean, and is 
*^ parts twelve hundred feet deep, is alone sufficient to 
Assure us, that the time may come, however distant, 
^hen a deluge may lay waste a considerable part of 
^-he American continent. No hypothetical agency is 
Required to cause the sudden escape of the confined 
Waters. Such changes of level, and opening of fissures, 
^s have accompanied earthquakes since the com- 
^i^encement of the present century, or such excavation 
^f ravines as the receding cataract of Niagara is now 



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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 mus'^t 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 



s 



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1111 



I 



r.h. v.] 



ANCIENT AND MODKRN CAUSES, 



135 



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i^ewer strata cannot be shaken by earthquakeSj unless 
the subjacent rocks are also affected ; so that the con- 
trast in the relative degree of disturbance in the more 
^J^cient and the newer strata^ is one of many proofs 
*hat the convulsions have happened in different eras, 
^^d the fact confirms the uniformity of the action of 
subterranean forces, instead of their greater violence 

^^ the primeval ages. 

Doctrine of Universal Formations. — The popular 
doctrine of universal formations, or the unlimited geo- 
graphical extent of strata, distinguished by similar 
Mineral characters, appeared for along time to present 
^^surmountable objections to the supposition, that the 
*^^rth's crust had been formed by causes now acting, 
^f it had merely been assumed, that rocks originating 
^^om fusion by subterranean fire presented in all parts 
^f the globe a perfect correspondence in their mineral 
Composition, the assumption would not have been 
^^travagant ; for, as the elementary substances that 
^nter largely into the composition of rocks are few in 
^^mber, they may be expected to arrange them- 
selves invariably in the same forms, whenever the 
^'ementary particles are freely exposed to the action 
^^ chemical affinities. But when it was imagined that 
sedimentary mixtures, including animal and vegetable 
r^i^ains, and evidently formed in the beds of an- 
^^^nt lakes and seas, were of a homogeneous nature 
throughout a whole hemisphere, the dogma pre- 
cluded at once all hope of recognizing the slightest 
^-Halogy between the ancient and modern causes of 
^^cay and reproduction. We know that existing 



rivers 



carrv 



down from different mountain chains 



sediment of distinct colours and composition : where 

the chains are near the sea, coarse sand and gravel 



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136 



ASSUMED DISCORDANCE OF 



[Book 



I. 



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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 ovef 
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 



1 











Ch. v.] 



ANCIENT AND MODERN CAUSES. 



137 



same internal composition; and all these were assumed 
*o be contemporaneous until the contrary could be 
shown, which, in the absence of evidence derived from 
^^irect superposition, and in the scarcity of organic re- 
gains, was often impossible- 
Innumerable other false generalizations have been 
derived from the same source; such, for instance, as 
^^e former universality of the ocean, now disproved by 
^^e discovery of the remains of terrestrial vegetation 
^^ strata of every age, even the most ancient. But I 
^hall dwell no longer on exploded errors, but proceed 
^^ once to contend against weightier objections^ which 
^^11 require more attentive consideration. 



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In 

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CHAPTER VI. 



AS TO THE 



FURTHER EXAMINATION OF THE QUESTION 

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. 157.) 
From the Plants of the Coal formation _ Northern limit of 
these fossils — Whether such plants could endure the long con- 
tmuance of an arctic night (p. 159.). 

Climate of the Northen Hemisphere formerly ..„„„.. . 
That 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 
remams were found to be intimately connected by 

generic affinity with species now living in „ 

At a 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, m support of the doctrine, that the heat of 



latitudes. 



warmer 



( 



41 



Ch. VI.3 



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, 
niore 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 
nothern parts of Europe and North America, and 
even to the Arctic regions, indications of the same 
^'evolution 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, 
^ell acquainted with the geographical distribution of 
organic beings in other parts of the globe, would have 
heen 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. 



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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 entertained on the subject. To insist on the 
soundness of these inferences, is the more necessary, 
because some zoologists have of late undertaken to 
vmdicate 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 proof s 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 

terranean, from the South of Spain to 



of the Med 



Med 



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- 



<ni 



* 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. 



1 



1 







*Ch. VI] 



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 
M^armer latitudes, the average size of the fossils- 

I collected several hundred species of shells in Sicily^ 
^t 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 
^ith those now living, but the relative abundance in 
"^hich 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, 
^nd pass from the region of active to that of extinct 
"^olcanos, we find the assemblage of fossil shells, in the 

r 

*nodern ( Subapennine) strata, to depart somewhat 
niore widely from the type of the neighbouring seas. 
-'■he proportion of species identifiable with those now 
living in the Mediterranean is still considerable ; but 
^t no longer predominates, as in the South of Italy, 
Over the unknown species. Although occurring in 
localities which are removed several degrees farther 
fi'om the equator (as at Sienna, Parma, Asti, &c.), the 
shells yield clear indications o£ a hotter climate. Many 




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142 



CHANGE OF CLIMATE 



tBookl 



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 



Wheneve 



Med 



it is not in the Northern Ocean, but between the 
tropics, that they must be sought f : 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 ) 
xvas said to attain larger average dimensions in a fossil, than in a 



recent state. 



f Thus, for example, Rostellaria curvirostris, found fossil by 
Signer 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. 



i,i 



L" W^ 



i' 



f 



Ch. VI.3 



IN THE NORTHERN HEMISPHERE. 



143 



as, for example, the genera 



in equinoctial regions, 
Pleurotoma and Cypraea.* 

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 
^^e common to all these groups, and some of them, 
l>oth freshwater and marine, are of species still living, 
Those found in the older, or Eocene, deposits of Paris 
^^d London, although six or seven degrees to the north 
^f the Miocene strata at Bordeaux, afford evidence of 
^ 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 
fewest) has more than counterbalanced the influence 
^hich latitude would otherwise exert, and this phenome- 
'^on clearly points to a gradual refrigeration of climate. 




rrr\ 



irC 



* 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 se^n in the museum at Turin, in 
1828, all procured by Professor Bonelli from the 
Subapennine strata of northern Italy. The genus 
Cypraea is represented by many large fossil species 
in the Subapennine hills. 



^^urotoma rotata. Subapennine kills, Italy, [a 



) 



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




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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 
hy 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 
i shall only state here, that among the extinct mam- 
malia thus entombed, we find species of the elephant, 
rhinoceros, hippopotamus, bear, hyaena, 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. 






I 






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9 







Ch. VI.] 



SIBERIAN MAMMOTHS. 



145 



(H. 



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, 
^ith 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 
Cliff, 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 
now 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- 
rupeds, 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 

r 

^ere found imbedded, together with the shells, in a 
deposit, which had evidently resulted from tranquil 
waters.f 

* Geol. Proceedings, No. 36. June, 1834. 
f Phil. Mag., Sept. 1829 and Jan. 1830. 



VOL. I. 



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CHANGE OF CLIMATE. 



[Book I. 



Wh 



must always bear in mind that the fossil individuals 
belonged to species of elephant, rhinoceros, hippopo- 
tamus, bear, tiger, and hyaena, 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 in a 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. 



( Ca7iis 



names 



.* ." 



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 

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 tio-er, identical 
with that of Bengal, is common in the neighbourhood 
of Lake Aral, near Sussac, in the fovty-fifth degree of 

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



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Ch. VI.] 



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 chain of 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. 

Ti, . „;„ oil f^.^ winter north of the Mouz- 

The last tiger killed, in 

18287on^lie Lena, in lat. 52^°, was in a climate colder 
than that of Petersburgh and Stockholm.f 

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 t ; and 
Pennant mentions that it is found among the snows of 



Mountains 



M 



irbis) 



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°.^ 

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 hyaena. Here the migration of all these 
species towards the' south is arrested by the ocean ; 

* Humboldt, Fraginens de G^ologie, &£. , tome ii. p. 388. 
Ehrenberg, Ann. des Sci. Nat., tome xxi. p. 387. 
f Ehrenberg, ibid. p. 390. 
^ Journ. of Asiat. Soc, vol. i. p. 240. 
§ Ehrenberg, ibid. 



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148 



^ 



CHANGE OF CLIMATE. 



[Book L 



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 SB,me 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. lat, 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 ivorv 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 



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MAP OF SIBERIA. 




149 






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150 



CHANGE OF CLIMATR 



[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. SG'^j 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 w^ere 

■ 

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. f 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 prisons). 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. 
I Nov. Com. Petrop. vol, 17. p. 584. 






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Ch. VI3 



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 sliin 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 bemg sp much 
warmer than that of the African rhinoceros.* 

After more than thirty years, the entire carcass of 
a mammoth (or extinct species of elephan-^^ 






) 



Mr 



was 



north. It fell from a mass of ice, in which it had been 
encased, on the banks of the Lena, in lat. TO^j 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 

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 
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 



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

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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 latitudes 
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 lo obtain any evidence in corroboration. Mr. Royle resided 



extreme 



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 solitarv indivi- 
dual was mentioned to him as having been seen at Delhi' with a 
good deal of long hair upon it. The greatest elevation, Ljs 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 Slst 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.,themonthof January averaging 45°,and June, the hottest 
month, 81° F. (Everest on Climate of Foss. Eleph., Journ. of 
Asiat. Soc, No. 25. p. 21.) 



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Ch. VI.] 



SIBERIAN MAMMOTHS. 



153 



V- 



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 
*'ange 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, 
1^^ 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 period 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 
^o 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, 
^s at present, and, during inundations, may have swept 
the carcasses of drowned animals into lakes, or the 
^^a, as do the Nile, Ganges, and other rivers in our 
own time.f 

In Siberia all the principal rivers are liable, like the 

+ 

* See Dr. Euckland's description of these bones, Appen. to 
Beechey's Voy. 

t See Book iii. chaps, xv. and xvi. 

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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 

m 

m 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 
maybe 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 reo-ion 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, torn, ii, p. 393. 



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Ch. VL] 



SIBERIAN MAMMOTHS. 



155 




I 






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 

r 

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 combmation of causes may 
have extended the low tract of land where manne 

shells and fossil bones now occur in Siberia. 






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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 
m summer. The musk oxen annually desert their 
wmter 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 m 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 
tlie 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 



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Ch. VL] 



CHANGE OF CLIMATE. 



157 



\ 



lead us to conclude that the mamuiotli, 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. 



9f climate proved hy fossils 



If we pass from the consideration of these more modern 
<ieposits, whether of marine or continental origin, in 
^hich 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, 
ntiany 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 
naany gigantic reptiles, some of them herbivorous, 
others carnivorous, and far exceeding in size any now 



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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 npw 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 kno^vn, tend to the same conclusion, the 
Cycadeae 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- 
diacese, 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. G^nerales sur la Nature de la V^g^tation, &c. Ann. 
des Sci. Nat, Nov, 1828, 








Ch. VI.] 



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 on the land. 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 
'' 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." * 

' ille Island, 



M 



The fossil plants brought from Melville 
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 



M 



which such a vegetation lived through an arctic night 



t 



It may seem premature to discuss this question 



* Prodrome d'une Hist, des Veget. Foss. p. 179. 
t 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, 
he at first stated, but that they agree with tropical forms of plants 



now 



in our English coal-beds. The Melville Island specimens, 
in the British Museum, are very obscure impressions. 

I Fossil Flora of Great Britain, by John Lindley and William 
Hutton, Esqrs. No. IV. 



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160 



FOSSIL PLANTS. 



F-" ^ 



[Book I 



until the true nature of the fossil flora of the arctic 



been 



the question has attracted some attention, let us as- 



MelviUe 



Island are strictly analogous to those of the strata of 
Northumberland — would such a fact present an Inex- 



? 



Melville 



plicable enigma to the vegetable physiologist i 

. Plants, it is affirmed, cannot remain in darkness, 
even for a week, without serious injury, unless in a 
torpid state; and if exposed to heat and moisture they 
cannot remain torpid, but will grow, and must there- 
fore perish. If, thei 

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 
mmd, 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. eo'' N., these plants have been success- 
fully cultivated in hot-houses, although there they 



* Fossil Flora, No. IV. 



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Ch. VI.] 



CHANGE OF CLIMATE, 



161 



1 



^ust 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 
^uch farther towards the pole they might continue to 
^ive, 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 lat. GS"" at least, where they would never 
Remain twenty-four hours without enjoying the sun's 
^%ht, they might still exist. 

Kor must we forget that we are here speaking of 
^i^ing species formed to inhabit within or near the 
t^'opics. 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 
t^e equator, others only at a distance from it. In the 
same manner the minimum of lights sufficient for the 
Uow existing species, cannot be taken as the standard 
*0f all analogous tribes that may ever have flourished 
^n the globe. 

But granting that the extreme northern point to 
^hich a flora like that of the carboniferous era could 
^ver reach may be somewhere between the latitudes 
^f 65° and 70^, we should still have to inquire whether 
the vegetable remains might not have been drifted 
*^om thence, by rivers and currents, to the parallel of 
Melville Island, or still farther. In the 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, 






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162 



f 



FOSSIL PLANTS. 



[Book 



r. 



and on shores where scarcely a stunted shrub can no^^ 



exist. 



Macke 



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.f It seems fair to pre- 
sume that the cpal 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 verv remote 
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. 

r 

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



* Fossil Flora, No. X. 

f This has been proved by Mr, Lindley's experiments. 



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\ 



Ch. VI.] 



CHANGE OF CLIMATE. 



163 



injured corals and chambered univalves of Igloolik 
(iat. 69JL° 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. 



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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.). 



^ 



of 



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 m 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 



( 



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I 



Cl^. VIL] CAUSES OF VICISSITUDES IN CLIMATE. 



165 



perpetual equinox, and uniformity of seasons throughout 
the year ;—^ that the planet enjoyed this * paradisiacal 
state until the era of 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- 
^^ity of its axis, and with that the varied seasons of 
the temperate zone, and the long nights and days of 
the polar circles. 



Wh 



en 



the progress of astronomical science had 
exploded this theory, it was assumed, that the earth 
^t its creation was in a state of fluidity, and red hot, 
^nd 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 
*^^ind directly to the beginning of things, it requires no 
^^pport 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 
^f the internal changes of an embryo world. 

But if, instead of forming vague conjectures as to 
^hat might have been the state of the planet at the 
^^a of its creation, we fix our thoughts on the connexion 
^t present existing between climate and the distri- 
hution of land and sea ; and then consider what in- 
fluence former fluctuations in the physical geography 
^f the earth must have had on superficial temperature, 
^^ niay perhaps approximate to a true theory. If 
doubts and obscurities still remain, they should be 
^Scribed to our limited acquaintance with the laws of 
Nature, not to revolutions in her economy; — they 



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

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



Diffusion ofh 



In considering the 



laws which regulate the diffusion of heat over the 
globcj 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 
parallel 

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 



s. 



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I 



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Ch. VII.] 



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 
^ines of equal winter temperature do not coincide 
^ith those of equal annual heat, or isothermal lines. 
The deviations of all these lines from the same parallel 
^f 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 

^^frents 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 
^^ounting to IF, or even in a few cases to 17° Fahr. ; 
^^d some places on the two continents, which have the 
s^nie mean temperature, differ from 7° to 13° in lati- 
tude.* The principal cause of greater intensity of 
^old 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 
^''om three to five thousand feet in height, and, on the 
^ther hand, the separation of Europe from the arctic 
^^^cle by an ocean. The ocean has a tendency to 
pi^eserve every where a mean temperature, which it 
Communicates to the contiguous land, so that it tempers 
the climate, moderating alike an excess of heat or cold. 



f 



funded an approximation to a true theory of the distribution of 
"eat over the globe. Many of these data are derived from the 
author's own observations, and many from the works of M. Pierre 
■Pi'evost, of Geneva, on the radiation of heat, and other writers, 
^^e Humboldt on Isothermal Lines, Memoires d' Arcueil, torn, iii- 
translated in the Edin. Phil. Journ. vol. iii, July, 1820. 
Humboldt's tables. Essay on Isothermal Lines, Scc, 







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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 









I 












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 
^n which the seasons are nearly equalized, and exces- 
*«^e 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 
legion 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- 



bu 



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At Pekin, in China, ivhere 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 
lilies of equal winter in Europe, for example, are often 
curved so as to reach parallels of latitude 9"^ or 10° 
uistant from each other, whereas the isothermal lines, 
^^ those passing through places having the same mean 
annual temperature, differ only from 4"" to 5"". 

^'^fiuence of currents and drift ice on temperature. — 
Among other influential causes, both of remarkable 
uiversity in the mean annual heat, and of unequal divi- 
lon of heat in the different seasons, are the direction 
ot currents and the accumulation and drifting of ice 
^^ high latitudes. The temperature of the Lagullas 



* On Isothermal Lines, &c 



Vol. I. 



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170 



GULF STREAM. 



[Book I 



\^ 



current is 10^ or 12° Falir. above that of the sea at 
the Cape of Good Hope ; for the greater part of its 
waters flow through the Mozambique channel, down 
the south-east coast of Africa^ and are derived from 
regions in the Indian Ocean much nearer the Hne, 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.f 

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 or 
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. or 
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 an 
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 7^ 
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 mean 

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



f Ibid. p. 153 



I Ibid. p. 25 






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Ch. VII.] INFLUENCE OF CURRENTS ON TEMPERATURE. I7l 

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 
^vith 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 

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 agam. 
The water of melted ice might be lighter, both as 

I 2 



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172 INFLUENCE OF CURRENTS ON TEMPERATURE. [Book I- 



(h 



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nearer the freezing point than the inferior water of the 



gulf stream.* 



V^ 



The great glaciers generated in the valleys of Spitz- 
bergen, in the Id"" 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 
Bayj on the contrary, on the west coast of Old Green- 
land, where the temperature of the sea is not mitic^-ated 
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 

r 

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 1S20 (Arctic Regions, vol. i. 
p. 210.)? he doubted whether salt water expanded like fresh 
water when freezing. Since that time Erman (Poo-o-endorf's 
Annalen, 1828, vol. xii. p. 483.) has proved by experiment that 
5ea-v.^ater does not follow the same law as fresh water as De 
Luc, Rumford, and Marcet 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 maxlviitin 
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. 

f Scoresby's Arctic Regions, voL i. p. 208.— Dr. Latta's Ob- 
servations on the Glaciers of Spitzbergen, &:c. Edin, New Phil. 
Journ, voh iii. p* J^7. 








mr- 



II * 111 






Ch. VIL] 



CHANGE OF CLIMATE. 



173 



latitude as the north of Prussia or the south of Scot- 
land, ice is found every where in digging 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 
^and, 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 sea on 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 
^accessible. And whereas, in the northern hemi- 
sphere, between the pole and the thirtieth parallel of 
^orth latitude, the land and sea occupy nearly equal 
^reas, the ocean in the southern hemisphere covers no 
l^ss than fifteen parts in sixteen of the entire space 
^eluded between the antarctic circle and the thirtieth 
parallel of south latitude. 



* 



Rennell on Currents, p. 95. 

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174 



DIFFERENCE OF CLIMATE IN NORTHERN [Book I 



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 
wmters are more mild than at Naples, and the summers 
not warmer than those at Paris, which is T 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 
42"^ 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 at a 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 a 
much larger difference existed, but that none was to 
be observed within the tropics, and only a small 






1 







* Humboldt on Isothermal Lines. 






I 





, 11 



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Ch. VII.] 



AND SOUTHERN HEMISPHERES, 



17 



o 



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 



Weddell 



pole. J3Ui tut; ic^^tA^i' ' -J -D 

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 ktitude, 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, accordmg 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 
laLde, or the same parallel as Yorkshire, the Ime 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 m Scotland, 
four degrees farther to the north, do not attam 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° 12' 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- 
graph. Soc. of London, ] 833, 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 aerial 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 



f 





Ch. VII.] 



AND SOUTHERN HEMISPHERES. 



177 



niore than double the area of Europe.* Some geo- 
graphers think that the late discovery of Graham's*and 



(between 



) 



of which Captain Biscoe believes to be of great ex- 
tent, has strengthened the probabiUty 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 
nuentioned, 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, 



bet 



+ One of these ( 



^as two miles in circumference, and 150 feet highj 
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 

* 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, bj 

^hom the sketch was made. Phil. Trans. 1830. 

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178 



CAUSES OF 



[Book T. 



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jbig'. 3. 




Iceberg seen off the Cape of Good Hope, April 1829. 

LaU 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 repiinds us that the ex- 
cess of eight days in the duration df the sun's presence 
in the northern hemisphere is not productive of an 
excess of annual light and heat ; since, according to the 
Jaws of elliptic motion, it is demonstrable that what- 
ever be the ellipticity of the earth's orbit, the WO 

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




I . ■ 



i.- 



Ch. VII.] 



CHANGES OF TEMPERATURE. 



179 



hemispheres must receive equal absolute quantities of 
light and heat per annum, the proximity of the sun m 
perigee exactly compensating the effect of its swifter 
motion* Humboldt, however, observes, that there 
ttiust 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 .f 

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 durmg 
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 coldwould 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, 
Vfhich may be thus stated : — " The amount of heat received by 
the earth from the sun, while describing any part of its orbit, is 
PJ-oportional to the angle described round the sun's centre." So 
that if the orbit be divided into two portions by a line drawn w 
any direction through the sun's centre, the heat received in de- 
scribing the two unequal segments of the ellipse so produced will 
be equal. Geol. Trans, vol. iii. partii. p. 298. j second series. 



f On Isothermal Lines. 



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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.— Yi2^vmg 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, 1st, 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. Sdly, 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. 

If it be objected, that the maximum of elevation of 
land and depth of sea are probably not constant, nor 
the gathermg 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 



\ [ 



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» I - ^ 



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I 



Ch. VII.] 



CHANGES OF TEMPERATURE. 



181 



tile same, the land is at one time more divided into 
islands than at another, a greater uniformity of climate 
ttiight 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 
^e 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 ^ea, would 
he represented, ona globe of about six feet in diameter, 
by a grain of sand less than one-twentieth of an inch 

ft 

in thickness.* 

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



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182 



CAUSES OF 



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[Book I 



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 so 
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, 
cession not greater in amount than one which the 
geologist can prove to have occurred in certain dis- 



an ac- 



Mediterranea 



withi 



m a com- 



tricts bordering the 
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 



I 



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'*♦* 



II 



I 



Ch. VII.] 



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 is now established that many of the existmg 
species of animals have survived great changes m 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, 
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 

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 



When 



longitude 



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184 



CAUSES OF 



[Book I. 



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transpositions of iclimate, 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, PI. I.) 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. 



'■^ 



f 



J 

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, I 



Ch. VII.] 



CHANGES OF TEMPERATURE. 



185 



in the present state of things, the mean heat of the 
climate is below that which the earth's surface, in its 
^ore ordinary state, would enjoy. This presumption 
^ould be heightened, were we to assume that the 
^ean depth of the Atlantic and Pacific oceans is as 
great as some astronomers have imagined * ; for then 
^e 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 
^s clear, that we have at present not only more than 
*he usual degree of cold in the polar regions, but also 

* See Young's Nat. Phil. Lect. xlvii.j Mrs. Somerville's Con- 
vex, 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 m^me ordre que la hauteur moyenne des continens et 
^es isles au-dessus de son niveau, hauteur qui ne surpasse pas mille 
Metres (3280 ft.)." Mec. Celeste, Bk. xi- et Syst. du Monde, 
P- 254. The expression " du meme ordre" admits in mathe- 
matical language, of considerable latitude of signification, and does 
^ot mean that the depth of the v^^ater 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- 
ticians, among others, Professor Airy, Mr. Lubbock, and Mr. 
^Vhewell, 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 
Pi*oceeded cannot give even an approximation to a solution of the 
Pi'oblem. Neither does Mr. Whewell believe in the alleged ap- 
Pi-oach 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.) 



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CAUSES OF 



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[Book I 



less than the average quantity of heat within the 



3 



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 

r 

possible that they may be brought about, nor of the 
time required for their accomphshment — 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 to 



I! 1 



. Y 





II 



> 



Ch. VIL] 



CHANGES OF TEMPERATURE. 



187 



L ■ 

I 



travel about 10° farther south in order to meet with 
the same dimate 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 mountams 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 
is 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- 



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CAUSES OF 



1 



[Book I' 



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. 



at the same 



But the refrigeration brought about a. .ut. ^nn. 
time m 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 m 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 m a state of constant and universal fJux 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. 

constantly going on in the 



That this circulation 

aerial 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 m the island of St. Vincent, in 1812, ashes 
fell m 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. 




at' 



A ill 



Ch. VII.] 



CHANGES OF TEMPERATURE. 



189 



■ it 1*^ 



th 



That a corresponding interchange takes place in 
e seas, is demonstrated, according to Humboldt, by 
^he cold which is found to exist at great depths be- 
^^een 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 /rom the north 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 f ; 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- 
uniting from the supposed alteration in the distribution 
^f land and sea, would be immediately communicated 
to the tropics, and from them its influence would 
^^tend to the antarctic circle, where the atmosphere 
and the ocean would be cooled, so that ice and snow 

Although the mean temperature of 
higher ladtudes in the southern hemisphere is, as 
before stated, for the most part lower than that of the 
^ame parallels in the northern, yet, for a considerable 
^Pace on each side of the line, the mean annual heat 
^f the waters is found to be the same in corresponding 
parallels. If, therefore, by the new position of the 



^ould augment. 



* 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 
^o south, or from south to north, but they do not affect the theory 
^f a constant circulation. 

t See note, p. 172.5 on the increasing density of sea- water in 
Proportion to the degree of cold. 



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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 wiU 
be evident that the mean temperature which may pre- 
vail at the same point at two distinct periods, may 
diifer 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 two 
distinct and somewhat distant epochs, a particular 
zone may at one time be under the influence of one 
class of disturbing causes, and at another time maybe 
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. 






V 



■i 



m^ 






Ch. VII.] 



' 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 m 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."* 



t 



and thus not only land as extensive as o^^'^^'^ting 
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 

r 

* See Scoresby's Arctic Regions, vol. i. p. .378. f I^' P' 



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192 



CAUSES OF 



S 



[Book I. 




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\ 

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 

and crocodiles more than 
twenty feet in length, which, at a former epoch, had 
multiplied between the tropics : and when they saw a 
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 



\ 



bones of fossil 



alligators 




■ h 



i 



Ch. VII.1 



CHANGES OF TEMPERATURE. 



193 



\ 



Oi 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 
^ 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 
^hich the mixture of the temperatures of distant 
Regions is facilitated throughout the globe, what 
Vigours might we not anticipate in a winter generated 
V the transfer of the mountains of India to our arctic 
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 
^ight, perhaps, render the globe uninhabitable. We 
are too ignorant of the laws governing the direction of 
^^bterranean forces, to determine whether such a crisis 
he within the limits of possibility. At the same time, 
^t may be observed, that no distribution of land can 
^ell be imagined more irregular, or, as it were, capri- 
^lous, than that which now prevails ; for at present, by 
drawing a line in a particular direction, the globe may 
he divided into two equal parts, in such a manner, that 
^^e hemisphere shall be entirely covered with water, 
^ith the exception of some promontories and islands, 
^hile the other shall contain less water than land ; and, 
^hat is still more extraordinary, on comparing the 
extratropical lands in the northern and southern hemi- 



VOL. I. 



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194. 



CAUSES OF 



[Book !• 



spheres, the lands in the northern are found to be to 
those in the southern in the proportion of thirteen to 



one 



? 



Let us no\^ turn from the con- 

d 



an 



To imagine all the lands, therefore, in high 
and all the sea in low latitudes, as delineated in the 
annexed plate (PL- 1.), would scarcely be a more 
anomalous state of the surface. 

Position of land and sea which might give rise to the 
extreme of 

templation of the winter of the " great year," 
consider the opposite train of circumstances which 
would bring on the spring and summer. 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. PI. L), would be undoubtedly to suppose an 

But if we con- 



extreme result of geological change, 
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 Blancf If then there 

* Humboldt on Isothermal Lines. 

f Humboldt, Tableaux de la Nature, torn. i. p. 112. 



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MAF S 

slie\\TiLg the positLOU 



OF LAND Amj SEA 



wJizdi 71 Off 7 it produce t7ie ej:tfefrte^ of 



HEAT AND COLD 



in the Climates of^ie 



GLOBE 



OLservatLons. 17ie^e Maps a/e i/zte/ulcd 
^ sJieiv ^lat Cbittinents t& Js-l^ziuZs havi/i^ 
*^ same> sh^zfye and relative dirn^isioTis 
f^ &tose 710W eaistin^ 7fri£/7u he placed so 
^^ to occupy ei^i&~ tJic e<fuatoiial or policr 



^*^:^07is 



■^ Ti^. ^f2 scaj'txly aii^ of the land eatends 
^^'07n die Equator towards die poles hc}'ond 

I 

^e SO^paralM of latitude arid in Iii^.2.. 
* ^'<^y small propoition of it eatends frora 
^f' polt^s towards the Eqiudor l/eyojid die 
-^Of paraU^ of latitjide. 





» 



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= ^ ^\ 



■m 



Ch. Yli.] 



CHANGES OF TEMPERATURE. ' 



195 



^ere 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 vegetatioii to their 
summits, and that nearly all signs of frost would dis- 
appear from the earth. 



Wh 



rays was in no 



1 



^'egion impeded, even in winter, by a coat of snow, the 
^ean 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 
^f lakes, therefore, and rivers, would be much hotter 
^n winter, and would be never chilled in summer by 
belted snow and ice. A remarkable uniformity of 
^Hmate would prevail amid the archipelagos of the 
temperate and polar oceans, where the tepid waters 
^f equatorial currents would freely circulate. The 
general humidity of the atmosphere would far exceed 
that of the present period, for increased heat would 
P^'omote evaporation In all parts of the globe. The 
^inds would be first heated in their passage over the 
tropical plains, and would then gather moisture from 
^he surface of the deep, till, charged with vapour, 
they arrived at extreme northern and southern re- 
g^ons, 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. 

learn from those who have studied the geo" 



We 



graphical distribution of plants, that in very low lati- 
tudes, at present, the vegetation of small islands remote 

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CAUSES OF 



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[Book I 



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, 
arid the tropical parts of New Holland, the proportion 
of ferns to the phaenogamous 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 woodsj 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. 

_ T 

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 



4* 



* Ad. Brongniart, Consid. Generales sur la. Nat, de la Veg^t- 

&c. Ann. des Sciences Nat. Nov. 1828. 



\ 



f 








I 



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I 



Ch. VIT.] 



CHANGES OF TEMPERATURE. 



197 



i 

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 
is 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 
»aarshes, 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 
^tuount 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 

r 

^ean 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 

^olcanos are in full activity, a much shorter period 
n^ay produce a sensible variation. The climate of the 



Malpais in Mexico 



differ 



niaterially from that which prevailed before the middle 
of the last century ; for, since that time, sixmountams, 



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198 



CHANGE OF CLIMATE. 



£Book T. 



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the highest of them rising sixteen hundred feet above 
the plateau, have been thrown up by volcanic erup- 



tions. 



I 



It IS by the repetition of an indefinite number 
of such local revolutions, and by slow movements 
extendmg simultaneously over wider areas, as will be 
afterwards shewn, that a general change of climate 
may finally be brought about. 



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199 



CHAPTER VIII. 



FARTHER EXAMINATION OF THE UUESTION AS TO THE 



DISCORDANCE OF THE 
OF CHANGE. 




CIENT AND MODERN CAUSES 



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- 

State of the surface when the grey wacke, or transition 
formations, originated — State of the same when the mountain 
limestone, coal-sandstones, and coal were deposited (p. 204.) 



mate 



Changes An 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.). 

L 

Whether the geographical features of 



m 



}f the deposition of the oldest fc 



I 



«w extremely hot climate.— l^ the sixth chapter, 
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 chmate 



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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 
iess importance may be expected to recur in future, 
" 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 greywacke, 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 m a sea of considerable extent. The fossils 
have been regarded by many naturalists «« ,.«. 
eating 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 oi 
ocean. The number and magnitude of the multilocular 
or chambered univalves, and of the corals, obtained 
from the limestones of this group, recall the forms novr 
most largely developed in tropical seas. Hitherto fev^ 
vegetable remains have been noticed, but such as are 



as in 



di- 



ll.' 



■^ F* 



; 








T 



Ch. VIII.] 



CHANGES IN PHYSICAL GEOGRAPHY. 



201 



Mentioned are said to agree more nearly with the 
plants of the carboniferous era than any other, and 
^ould therefore imply a tropical and humid atmo- 



sphere. 



^ 



rhonifi 



■This group comes next in the 



Qi'der of succession, and one of its principal members, the 
fountain limestone, was evidently a marine formation, 
^s is shewn by the shells and corals which it con- 
tains. That the ocean of that period was of consider- 
*le 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 
■^nierica, towards the borders of the arctic sea.f 
The coal itself is admitted to be of vegetable origin 



9 



* Mr. Murchison, during his investigations of the English and 
^elsh transition rocks, has not met with any vegetable remains 
«f latid plants; but MM. Elie de Beaumont, Virlel, 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 
^oakplants of Munster, in Ireland, belonged to the transition 
'^ocks ; but he has lately retracted his opinion, and believes that 
^be coal and plants alluded to occur in the carboniferous series. 

t it appears from the observations of Dr. Richardson, made 
^^ring 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- 
reous formation, stretching towards the mouth of the Mackenzie 
river, in which are included corallines, productse, terebratulae, 
^c. having a close affinity in generic character to those of our 
"fountain limestone, of which the group has been considered the 
equivalent. There is also in the same region a newer series of 
'Strata, in which are shales with impressions of ferns, lepidoden- 
^rons, and other vegetables, and also ammonites. — -P^*^^^^^'^* 
^f'Geol Soc, No. 7. p. 68. March, 1828. 

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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, hoF- 
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 
Uiis group has been thought by some geologists, as by 
MM. Sternberg, Boue, and Adolphe Brongniart, to 
favour the hypothesis of the strata havin ...„.._ 
fromthe waste of small islands placed in rows, and 
formmg the highest points of submarine 
chams. 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. 



g resulted 



mountain 






Ch. VIII.] 



AKD 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 * , ■ . n 

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 
bcean in a tropical and humid climate. 

There is, as yet, no well-authenticated instance of 
the remains of a saurian animal having been found in a 
member of the carboniferous series.f 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 inferrecl 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. Centrales sur la Nat. de la Veg«. 

&c., Ann. des Sci. Nat. Nov. 1828. _ . ^^^ 

t The supposed saurian teeth found by Dr. ^^^^^"^ ^\^^^ 

carboniferous limestone of Burdie House, near ^^'"!'"''^ ' 
since been clearly referred by Dr. Agassiz to sauroidal s . 



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204 



CHANGES OF THE SURFACE 



[Book I. 



r 

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 
land 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 ihat 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 
soutliern 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 hfe. 

So fai^ then, the examination of the phenomena 
exhibited by the greywacke and carboniferous ^roups 
accord well with the prevalence of such a st'ate 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, 
continuity of marine deposits over vast spaces - 
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. 



the 
the 



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Ch. Vlll.] 



AND CLIMATE CONTEMPORANEOUS. 



205 



? i; 



^0 establish the fact of the northern hemisphere hav- 
^^g 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. 



of the carhonifi 



iraphy between the forn 
strata and the chalk. 



^e have evidence in England that the strata of the 
ancient carboniferous group, already adverted to, were, 
^11 many instances, fractured and contorted, and often 
thrown into a vertical position before the deposition of 
^ome of the newer secondary rocks, such as the new 

^^d sandstone. 

Fragments of the older formations are sometimes 
^^cluded in the conglomerates of the more modern ; and 
Some of these fragments still retain their fossil shells 
^^d corals, so as to enable us to determine the parent 
^ocks from whence they were derived.* There are 
Qther proofs of the disturbance at successive epochs 
of diflFerent 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 
^^ep. 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 

**uncated edges of the coal and mountain limestone, and contains 

^^^ed and angular fragments of that limestone, in which its charac- 

^^J^istic mountain-limestone fossils are seen. For accurate sections 

^^strating the disturbances which rocks of the carboniferous 

eries underwent before the newer red sandstone was formed, the 

^^ader should consult the admirable memoir of the south-western 

«oal district of England, by Dr. Buckland and Mr. Conybeare, 

^eol. Trans, vol. i. second series. 




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206 



CHANGES OF THE SURFACE 



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[Book 



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(fi 



to the chalk 



■) 



■^ 



appears to have approached to that of the larger 
islands of the equatorial zone; such, for example, as 
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 upper 
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. -j- 

It might at first appear, that the position of a con- 
tinent so far to the 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 or 



* Ad. Brongniart, Consid. 

&c. Ann. des Sci. Nat., Nov. 

I See Book iv. chap, xxiii. 



Generales sur la Nat. de la Veg*^^ 
1828. 



I 





I 




Ch. VIII.] 



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 
^ere prolonged from the equatorial to the temperate 

Zone. 

Changes during the tertiary periods.— It vi^ill be 
seen hereafter that the Maestrlcht 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- 
«Jence 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, f On comparing the tertiary formations of dif- 
ferent agesj 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 
^ords, 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, 

r 

I 

* See Book iv. chap, xxiii. 

t See chaps, xxi. and xxii. B. iv. on the period of the elevation 

of the chalk of the S. E. of England. 



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208 



CHANGES OF THE SURFACE 



[Book I. 



during all these successive tertiary periods, there 
are signs of a great increase of land in European 



latitudes. 



(PL IL) 



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 befor6 
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 (PL IL 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 




^fa. VIIL] 



AND CLIMATE CONTEMPORANEOUS. 



209 



r 

this comparatively modern period ; some tracts, which 
^ere previously land, having gained in altitude, or, on 
^^^ contrary, having sunk below their former level, 
^^*^hin the period alluded to. 

The evidence that this rise of land did not take 
P'^ce all at the same time, is most striking. Several 
Italian geologists, even before the time of Brocchi, 
W justly inferred that the Apennines were elevated 
Several thousand feet above the level of the Medi- 
^^i^ranean,* before the deposition of the recent Sub- 
^Pennine beds which flank them on either side. What 
^^w constitutes the central calcareous chain of the 

ennines 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 
^^nce been raised from one to two thousand feet, by 
^hich movement the ancient shores, and, for a certain 
^^tent, the bed of the contiguous sea, have been laid 
^^y, both on the side of the Mediterranean and the 
Ad 

The nature of these vicissitudes will be explained 
"y the accompanying diagram, which represents a 




riatic. 



Fig 4. 




transverse section across the Italian peninsula. The 
^^^clined strata A are the disturbed formations of the 
■Apennines into which the ancient igneous rocks a are 
^^^pposed to have intruded themselves. At a lower 
level on each flank of the chain are the more recent 




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210 



CHANGES OF THE SURFACE 



[Book I. 



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shelly beds b b, 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. Tliey 
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 a 
great zone of tertiary rocks of different ages, both on 
their southern flank towards the plains of the Po, and 
on the side of Switzerland and Austria, and at their 
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- 
tamed 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. 





Ch. VIIL] 



AND CLIMATE CONTEMPORANEOUS. 



211 



^e 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 
^ith the adjoining bed of the sea, so that the moun- 
tains of Europe may rival the Andes in elevation ; in 
^vhich case the deltas of the Po, Adige, and Brenta, 
^ow encroaching upon the Adriatic, might be uplifted 
So 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 



Mont 



th 



y 

ousand feet, since the deposition of some of the 
iiewer 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, f 



* 



firm 



This observation, first made by M. Boue, has been since con 



t M. Elie de Beaumont, Ann. des Sci. Nat., Dec. 1829, p. 346. 




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212 



CHANGES OF THE SURFACE 



[Book I 



The remarkable break above alluded to, betNveen 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 
oj 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- 
plamed in regard to vicissitudes of temperature are 
sound, it will follow that changes of equal magnitude 
m the geographical features of the globe, may at dif- 
ferent periods produce very unequal eifects 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, 

!!!lL ! ""T ""^ ''^^^'^^^^^ ^" climate would be by no 
"^"""" ""'^""" " ^^t us imagine the quantity of land 
between the equator and the tropic in one hemisphere 
to be to that m 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 



means uniform. 



* See Book iv. chap. 23. 



» 





Ch. VIII.] 



AND CLIMATE CONTEMPORANEOUS. 



213 



the line to the other, from the southern hemisphere, 
f^r example, to the northern. Now this need not 
effect 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 
^ean 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 
^Ways 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. 



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214 



EXPLANATION OF MAP SHEWING 



[Book I 



Map 



by imter since the commencement of the deposition of the older 
or Eocene Tertiary strata. {Strata f the Paris and London 
Jtiasins, <^c. ) * 



This map wil] 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, 
dunng 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 



) 



(those 



IS composed. The species, moreover, of marine and 
freshwater testacea, of which the remains are found 
m these older tertiary formations, are not entirely dis- 
tinct from such as now live ; a proportion of more than 
three m a hundred of the fossils having beenidentified 
with species now living.f Yet, notwithstanding the 

* Constructed chiefly froni M. Ami Bout's Geological Map 
of Europe. 

f See Book iv. cb. 5, 

4 



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The portion mM thus compt^hetids the present Sea, together with the jpace whuh ciia he 

%rovM to 1t<tve b^^m ^uhmrrt^^ during some paii: or* thr period above meruiotu^. Hie whol£ 
nrea tfm^v (Mmeat^ wj/iy never hnve he0i suhmer<fe^ at one time bat AiWermt paits lit 
Uiueessianifetitis prttbable titat the proportion of dry land ha^ daring the whole 
\ period hern on the uttTetise. 

Tlie sf?tnr eoJoured lied A- Blue mntf never have beert under Witter ^ince the comniencement 
ot^ th^ rtvw under rofhndemtfon but thtJ^ inffrenre 7w«p on netftitive evtdtnee and mnif 

retfiaW hcreafrrr to be modi^ett , 

Pruruvy OJtd Titmsition. Formaiions { The space M^ whi^ is eAher uiiicxplored ^eclo^icalh^ 

or is tDo Uttk laun^n. ito warrant an opinion rcspcctii^ 
Secondary Df \ its submcraenee duriiuf the tcrtiarY cpo<h. 



Sor €1 moi^ drtaihJ atpfanaiion t^^fhis Map.see B<M?hlJ^ap.S. 



•5'q 



^<^ruhn:TuUisM fyJohn Mun^a^Mhei/ui/^s Stre^. 



SnaraMed I'v J.&tird.ne^^ 






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Oh. VIII. 



] CHANGES IN PHYSICAL GEOGRAPHY. 



215 



L 

L 

Comparatively recent epoch to which the retrospect Is 
carried, the variations in the distribution of land and 
^^a depicted on the map form only a part of those 
^hich must have taken place during the period under 
Consideration. Some approximation has merely been 
'^ade to an estimate of the amount of sea converted into 
^«'*f? in parts of Europe best known to geologists ; but 
^^^ cannot determine how much land has become sea 
'iuring the same period; and there may have been 
■■^Peated interchanges of land and water in the^ same 
I^^^ces, changes of which no account Is taken in the 
'^ap, and respecting the amount of which little accu- 
'"^'^e information can ever be obtained. 

I have extended the sea In two or three Instances 
,^yond the limits of the land now covered by tertiary 
°^'ttiations, because other geological data have been 
ained for Inferring the submergence of these tracts 
^[^er the deposition of the tertiary strata had begun. 
'^^'^'JS I shall explain, in the 4th Book*, my reasons for 
^"ticluding that part of the chalk of England (the 
^f th and south downs, for example, together with the 
'fitervening secondary tracts) continued beneath the 
^^^ until the Eocene or earliest tertiary beds had 
^§un to accumulate. 

A strait of the sea separating England and Wales 
^^s also been introduced, on the evidence afforded by 
shells of existing species found in a deposit of gravel, 
^^■^d, loam, and clay, called the northern drift by 
^^' Murchison, who has traced it from Lancashire 
^0 the Bristol channel, over the space indicated In the 
^ap. 4- ]y[j._ Trimmer has discovered similar recent 



b 



obt 

aft 



Ch» "xxi. and xxii. 



t See Proceedings of Geol. Soc. vol. ii. p. ^^^' 






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216 



EXPLANATION OF MAP SHEWING 



[Book 

Wale 



t 



and on Moel Trjfane, 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 the 
sea over part of the eastern shore of Ireland. 

A portion also of the primary district in Brittany i^ 
divided into islands, because it has been long known to 
be covered with patches of marine tertiary strata; an^l 
when I examined the disposition of these, in company 
with my friend, Captain S. E. Cook, R. N., in 1830, 1 
was convinced that the sea must have covered much 
larger areas than are now occupied by these small an^ 
detached deposits. 

The former connexion of the White Sea and the 
Gulf of Finland is proved by the fact that a broa^l 
band of tertiary strata extends throughout part of the 
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 is 
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 level 
of the sea, attests the comparatively recent date of the 
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. 



\ 



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7 





Ch.VlII.] 



CHANGES IN PHYSICAL GEOGRAPHY, 



sn 



T 



On tlie other hand, a considerable space of low land 
^long 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 
tl^at coast, known to have taken place during the his- 
torical era, leave no room for doubt that the boundaries 
of the gulf must have been greatly contracted within 
^ 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 
iines, because they are covered with clay, sand, and 
ei'ratic 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 
Represented 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 



/ 



The difficulty, or 



Rather the impossibility, of restoring the geography of 
the globe as it may have existed at any former period. 



^Specially a remote one, consists in this, that we can 



only point out where part of the sea has been turned 
^^to land, and are almost always unable to determine 
^hat 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. 



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218 



CHANGES OF THE SURFACE 



[Book 



I. 



(the conversion of sea into land) known to have been 
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 been 
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 is 
now greatly in excess beyond the average proportion 
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 there 
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 in 
some cases to occasion a rise of several thousand feet 



\ 



* See Book iv. chap. iii. 



J 4 





^ 



'^ 



Ch. VIII.] 



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 maybe 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 BB" 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 sea and 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- 




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* It 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 
extinction of species. 

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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 
v/ell as hotter climates than those now estabUshed.=* 
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 (PI. I. fig. I.) 
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 

* Allgenveine Literatur Zeitung, No. cxxxix. July, 1833. 






i . 



I 





Ch. VIIL] 



AND CLIMATE CONTEMPORANEOUS. 



221 



globe, it IS as 9 to 23 * Hence it ought not to sur- 
P-fise 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^'" 
every where the signs of a higher temperature. The 
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 
'^y the sea being 110,849,000, and that by land, 37,673,000 ; so 
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. ]at. and the pole occupies a space 
<^hout equal to that of the sea, and the land between the 30° S. at. 
and the antarctic circle about -^-^ of that zone. 

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222 



CHANGES OF THE SURFACE 



[Book I 



3 00 



th 



heat, at the same time that it has contracted its di- 

H 

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 
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 
in a 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. torn, xxvii. 
p. 136. Oct. 1824. 



1 




#t 



Ch. VIIL] 



AND CLIMATE CONTEMPORANEOUS, 



223 



t^^e 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 
ctepths, flow out upon the surface, and before they 
consolidate emit much light and heat. Inwhat manner 
does the igneous and luminous matter thus withdrawn 
fvom 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 In^«^"°»" 
of the Earth, read to the Academy of Sciences, 4th June, 1827. 



Edin. New Phil. Journal, No. viii. p- 273. 



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ASTRONOBIICAL CAUSES OF 



IBook I. 



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 lightand 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 conflaera- 



(if such it be) 



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.* 



^ff 



Sir 



John Herschel has lately inquired, whether there are 
any astronomical causes which may oifer a possible 
explanation of the difterence 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 Astronomjr, § 337 



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f'h- VIII.] 



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 
t^e a 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, 
is 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 

Sat . 

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 

Geol. Trans, second series, vol. iiu p. 295. 



urn, would cause in the earth's orbit, and in each 



of the 



minor axis. 



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226 



CHANGE OF CLIMATE. 



[Book I 



spaces beyond the earth's atmosphere ; a matter still 



MM 



Herschel have arrived at very difFerent 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* 



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227 




mm 



CHAPTEK IX. 



Hrther discussion of the question as to the dis- 
cordance OF THE ancient AND MODERN CAUSES OF 



CHANGE. 



Evidence 



Theory of the progressive development of organic hfe 
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 
suc^cessive development not confirmed by the admission that 
man is of modem origin — Introduction of man, to what 
extent a change in the system (p. 248.). 



Progressive development of organic ?i/e.— In 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 
tlie 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 

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228 



THEORY OF 



[Book I 



d 



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 in a still 
more recent class ; and it is only in the loose and 
slightly consolidated strata of gravel and sand, ai 
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, 
m 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 a former 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 oi: 
thmgs, and a succession of destructions and creations 
preparatory to the existence of man."* 



* 



Sir H. Davy, Consolations in Travel, Dialogue III. " The 
Unknown." 






I 



Ch. IX.] 



PROGRESSIVE DEVELOPMENT. 



229 



I . , , 






f 






In the above passages^ the author deduces two im- 
portant conclusions from geological data : first, that in 
*^^e successive groups of strata, from the oldest to the 
^ost recent, there is a progressive development of 
^^ganic life, from the simplest to the most complicated 
forms ; — secondly, that man is of comparatively recent 
^^igin. It will be easy to shew that the first of these 
Propositions, though very generally received, has but 
^ 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 
^^ay have been uniform from the beginning, or rather 
from the era when the oldest rocks hitherto discovered 

^ere 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 
geologists who are in possession of all the data now 
Established respecting fossil remains, will for a moment 
Contend for the doctrine in all its detail, as laid down 
oy the great chemist to whose opinions we have re- 
ferred; but naturalists, who are not unacquainted with 
recent 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 
Zoophytes, testacea, and a few fish. Plants of a less 
Simple structure succeeded in the next epoch, when 
oviparous reptiles began also to abound. Lastly, the 
terrestrial flora became most diversified and most per- 




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230 



THEORY OF 



[Book 1 



as 



feet 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, 

r 

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 oi 
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 oi 
particular families be declared to depend on a certaii^ 
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 
flourish for ages before the dicotyledonous order can 
be established, then is the small proportion of the latter 
fully explained ; for in this case, whatever may have 
been the mildness or severity of the climate, they could 
not make their appearance. 



\ 



H -^ 



Ch. IX.] 



PROGRESSIVE DEVELOPMENT. 



231 



Before we can infer an elevated temperature in high 
latitudes, from the presence of arborescent FernSj 
^ycopodiacese, and plants of other allied families, we 
^^st be permitted to assume, that at all times, pasty 
Present, and future, a heated and moist atmosphere 
Pervading the northern hemisphere has a tendency to 
Produce in the vegetation a predominance of analogous 

^ypes of form. 

In the ancient strata of the carboniferous era, be- 
tM^een 200 and 300 species of plants have been found. 
^^ these, say the authors of the " Fossil Flora *," no 
traces have been as yet discovered of the simplest 
^'^rms of flowerless vegetation, such as Fungi, Lichens^ 



a 



epaticse, 



Moss 



\ 



appear in their room Ferns, Lycopodiacese, and sup- 

r 

posed Equisetacese, the most perfectly organized 
^^yptogamic plants. In regard to the remains of 
Monocotyledons of the same strata, they consist of 
P^lms and plants analogous to Dracaenas, Bananas, 
^^^d the Arrow Root tribe, which are the most highly 
developed tribes of that class. Among the dicotyle- 
'^ons of the same period coniferous trees were abund- 
^^t, while the fossil Stigmarise, which accompany 
^^em, belonged probably to the most perfectly or- 
ganized plants of that class, being allied to the Cactese 

^^ Euphorbiacese- " But 
^^i^e authors, " that it could be demonstrated, that 
^^ither Conifers nor any other dicotyledonous plants 
existed in the first geological age of land plants, still 
*^e 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 WilliaiB 
Button, Esquires, London, 1832* Preface* 



supposmg. 



continue the 



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THEORY OF 



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[Book !■ 



monocotyledons are inferior in dignity, or, to use a 
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 greywacM, afi^ 
carboniferous strata. — By far the largest part of the 
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 of 
investigation, since all are now agreed that the greater 
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 froro 
the absence of fossil bones of mammalia in the older 
rocks, that the highest class of vertebrated animals did 
not exist in the remoter ages. There are regions at 
present, in the Indian and Pacific oceans, co-extensive 
in area with the continents of Europe and North 
America, where we might dredge the bottom and dra^ 
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 Ocean 
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 



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Ch. IX.] 



PROGRESSIVE DEVELOPMENT. 



233 



"e sceptical as to the accuracy of their statements? 
3^nd 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 
'i^adrupeds are swept by rivers far out into the open 
^^a, and still rarer the contingency of such a floating 
^ody not being devoured by sharks or other predaceous 
^sh, such as were those of which we find the teeth 
Preserved in some of the carboniferous strata. But if 
^^e carcass should escape, and should happen to smk 
"^^ere sediment was in the act of accumulating, and 
*^ 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 

that mere point in the bed of an ancient 
'^cean, where the precious relic was entombed ? 
^e 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 amphi- 
"*"ot<s animals, that we should meet with a single 
skeleton of an inhabitant of the land ? 

Clarence, in his dream, saw, "in the slimy bottom 

^f the deep," 



exact 



spot 



Can 



. a thousand fearful wrecks ; 

A thousand men, that fishes gnaw'd upon ; 
Wedges of fold, great anchors, heaps of pearl. 

^ad he also beheld, amid " the dead bones that lay 
scattered by," the carcasses of lions, deer, and the 




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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 
fehakspeare. So daring a disregard of probability and 
violation of analogy would have been condemned as 
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- 
tamed respecting the doctrine, of successive develop- 



ment. 



I 

In the first place it should be stated, that faint traces 
of animal remains make their appearance in strata of aS 
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 oi 
" 'w, for example, scales and bones of fish have 
been found.* In these ancient rocks we cannot ex- 
pect to bring many vertebral remains to light until vfe 
have obtained more information respecting the zoo- 
phytes and testacea of the same period. The rarer 
species cannot be discovered until the more abundant 
have been found again and again ; and 



LudI 



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 im- 
portance to the absence of birds and mammalia, l^ 

, r 

* Murchison, Proceedings of Geol. Soc. No. 34. p. 1 3. , 



\' 




)«! 



^^' IX.] 



PROGRESSIVE DEVELOPMENT. 



235 



4 

•"^cks of high antiquity many organic forms have been 
obliterated by various causes, such as subterranean heat 
^^^ the percolation of acidulous waters, which have 
operated during a long succession of ages. The number 
^f organic forms which have • disappeared from the 
•^Ifiest strata may be conjectured from the fact, that 
^^eir former existence is in many cases merely revealed 
^° us by the unequal weathering of an exposed face of 
"■ock, 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 
^^bothi 



th 



West 



-^s, but no well-authenticated instance is recorded 
""^ a fossil reptile from this formation.* Neither have 
^^y reptilian remains been met with in the incumbent 
Carboniferous group, either in the mountain limestone, 
^^ in the shales and sandstones of the coal. The 
^^Pposed saurian teeth found by Dr. Hibbert in car- 
boniferous strata, near Edinburgh, have been lately 
*ewn by Dr. Agassiz to belong to sauroidal fish, or 
^^b of the highest rank in structure, and approaching 
"^ore nearly in their osteological characters than any 

^''bers to true saurians. 

It Would be premature to conclude that no bones of 
'■^Ptiles are to be found in the carboniferous formation, 
because it is only within a few years that several dis- 

* Scales of a tortoise nearly allied to Trionyx, are stated in the 
^^ol. Trans, second series, vol. iii. part 1. p. 144,, to have been 
'I'^^nd abundantly in the bituminous schists of Caithness, in Scot- 
^'^d, and in the same formation in the Orkneys. These schists 
'^a^e been shewn by Professor Sedgwick and Mr. Murchison to be 
^f the age of the old red sandstone. But M. Agassiz has lately 
decided that the scales in question are those of a fish (see figure of 
*^>»5 plate 16., Geol. Trans., same part). 



f, 
1 




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ii 




236 



THEORY OP 



[Book 



I. 



tinct species and genera of fish have been ascertained- 
to abound in the same. It should also be recollected. 
that if we infer from the fossil flora of the coal, an^ 
other circumstances before enumerated, that our lati- 
tudes were occupied at the remote period in question by 
an ocean interspersed with small islands, such islands 
may, like those of the modern Pacific, have been almost 
entirely destitute of mammalia and reptiles.* 

In regard to birds, they are usually wanting in "- 
posits of all ages, even where fossil animals of tl'^ 



de 



t 



the 



There was evidently a long period, of which 
formations from the magnesian limestone to the chall^ 
inclusive may be said to contain the history, when 



earth 



the 



reptiles of various kinds were largely developed'on 

their remains are particularly numerous in the 



has 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 ampli'' 
bious habits, which inhabit rivers, like the hippopo- 
tamus, otter, and beaver; others exclusively aquatic 
and marine, like the seal, whale, and narwal, so '^^ 
the early ages under consideration, there were ter- 
restrial, winged, and aquatic reptiles. There wer^ 
iguanodons walking on the land, pterodactyles winging 
their^ way through the air, monitors and crocodiles '" 
the rivers, and the ichthyosaur and plesiosaur in the 
ocean. It appears also that some of these ancient 
saurians approximated more nearly in their organis- 
ation to the type of living mammalia than do any oi 
our existing reptiles. 

I shall not dwell here on a question, which wiH 



* 



See p. 204. 



t See Book iii. ch. 15. 



I 



r 





I. 



■7 



Ch, ix_ 



aft 



3 



PROGRESSIVE DEVELOPMENT. 



23 



i 



erwards be discussed more fully, how far the almost 

Gut' 
^^^^ suppression of one class of vertebrata and the 






pment of another, as, for example, the pre- 



th 



evelo 

^^inance of reptiles over mammalia, or of these over 

^Ptiles, may be reconcileable with the notion of con- 

^^^ and uniform laws governing the distribution of 

^^^al life at particular periods.* I shall now merely 

If^ the reader's attention to a striking exception to 

general rule of the non-occurrence of any signs of 

^^^-blooded quadrupeds in secondary rocks. 

^^ the oolite of Stonesfield, a rock which has been 

, ^^^ ascertained to hold a somewhat inferior position 

^^^^ great oolitic series, the jaws of at least two 

P^cies of small mammiferous quadrupeds have been 



(see fig. 5.j, was examined by M 



Pronounced by him to be allied to the didelphis. 

^^^rding to this naturalist, it was probably a small 

. ^^^ivorous animal not larger than a mole, yet differ- 

§ from all known carnivora in having ten teeth in a 



Fig. 5. 



Natural she. 




Jctw of a mammiferous quadruped, from the slate of Stones- 



feld near Oxford.-^ 



% 



Book 



t Thi 



iv. chap, xxiii. 



Pubr ^^ ^^"^^ ^"^^' ^' ^ ^^ ^^^^^ ^ drawing by Professor C. Prevost, 
Wished Ann, des Sci. Nat., Avril, 1825. The fossil is a lower jaw. 



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238 



THEORY OF 



[Bool^ 



I. 



Another specimen now in London, in the collection 
of Mr. Broderip, consists also of a lower jaw, ^^^ 
belonged certainly to a quadrupedof a distinct species^ 
or even genus (see fig. 6.) for the number of teetl^ 
is different, and agrees precisely with that of ^^^ 
living didelphis. 

Fig. 6. 




f\ 




Natural size. 



Lower jaiv of Didelphis JB ucMandi^ from Stonesfield,^ 

1. The jaw magnified twice in length. 

2. The second molar tooth magnified six times. 



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adhering by its inner side to the slab of oolite, in which it is ^^^^ ' 
The form of the condyle, or posterior process of the jaw, 'S ^^^^ 
tinctly seen, an impression of it being left on the stone, altht>^^ 
the bone is wanting. The anterior part of the jaw has been V^^' 
tially broken away, so that the fangs of six molar teeth are ^^^^ 
fixed in their sockets, the form of the fangs being characteris*^^ 

of the mammalia. The enamel of some of the teeth is well P^^' 



serv 



ed. 



Mr 



* This figure (No. 6.) is taken from the original, i" ] 
Broderip's collection. It consists of the right half of a lower j^^' 
of which the inner side is seen. The jaw contains seven nflO 
teeth, one canine, and three incisors, but the end of the jaw is ^^ 





I. 



in 



l^i 



e 




Ch. IX.] 



PROGRESSIVE DEVELOPMENT. 



239 



The occurrence of these individuals, the most ancient 
^^niorials yet known of the mammiferous type, so low 
^^n in the oolitic series, while no other represent- 
atives of the same class have yet been found in the 
^^perior secondary strata, either in the Middle or 
pPper Oolite, or in the Wealden, Green Sand, or Chalk, 
^^ ^ striking fact, and should serve as a warning to us 
Against hasty generalizations. So important an excep- 
^ ^^^ to a general rule may be perfectly consistent with 
,^^ conclusion, that a small number only of mammalia 
^^habited European latitudes when our secondary rocks 
^^^e formed ; but it seems fatal to the theory of pro- 
§**essive development, or the notion that the order of 
P^^cedence in the creation of animals, considered 
^l^ronologically, coincided with the order in which 
^^y Would be ranked according to perfection or com- 
plexity of structure. 

^f 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 
^^inisphere had been entirely altered. Large inland 



lak 



es had become numerous, as in Central France and 



l^^^^y other countries. There were gulfs of the sea^ 
^^to which considerable rivers emptied themselves^ 
^here strata were formed like those of the Paris basin, 
/^^ere were then also littoral formations in progress^ 



^^•^Jj and traces of the alveolus of a fourth incisor are seen. 

^th this addition, the number of teeth would agree exactly with 

ose of a lower jaw of a didelphis. The fossil is well preserved 

^ slab of oolitic structure containing shells of Trigonise and 

*^^r marine remains. Two other jaws, besides those above 

^^presented, have been procured from the quarries of Stonesfield, 

See Broderip, Zool. Journ. vol, iii. p. 408. 








!* 




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240 



THEORY OF 



[Book I- 



> 



> 



such as are indicated by the EngUsh Craff, and the 
i'"'«/Mn* of the Loire. The state of preservation of the 
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 1 100 species 
of testaceahavebeen found in the beds of the Parisbasin* 
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 the 
testacea which inhabited the ancient seas of northed 
.latitudes at those remote epochs than of the species 
now living in the same parallels in Europe. 

Paris basin. — The strata of the Paris basin are 
partly of freshwater origin, and filled with the spoi'^ 
of the land. They have afforded a great number o^ 
skeletons of land quadrupeds, but these relics are con- 
fined almost entirely to one small member of the group' 
and their conservation may be considered as having 
arisen from some local and accidental combination 
of circumstances.* On the other hand, the scarcity 
of terrestrial mammalia in submarine sediment is eluci' 
dated, in a striking manner, by the extremely smal^ 
number of such remains hitherto procured from the 

calcaire grossier, one of the formations of the Parisian* 
series, f 

London clay— Plastic clay. — The inferior member 
of our oldest tertiary formation in England, usually 
termed the plastic clay, has hitherto proved as destitute 
of mammiferous remains as our ancient coal strata ; 
and this point of resemblance between these deposits 



* Book iv. ch. xviii. 



t Ibid. 



w I 



1. 



I 



Ch. IX.] 



PROGRESSIVE DEVELOPMENT. 



241 



* ' .- ■ ■ 

IS the more worthy of observation, because the lignite, 
^^ the one case? and the coal in the other, are exclu- 
sively composed of terrestrial plants. From the Lon- 
don clay we have procured three or four hundred 
species of testacea, but the only bones of vertebrated 
^^imals 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 
^f 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 
^xahedinthe scale of organization than reptiles are 
discoverable. It should, however, be stated, that in 
^ freshwater formation, resting upon the London clay, 
^^ the Isle of Wight, and hke it belonging to the Eocene 
^Poch, some mammiferous remains have recently been 

found. 

Subapennine beds.— K\t\iOMg\i the Subapennine strata 

bave been examined by collectors for three hundred 
y^ars, and have yielded more than a thousand species of 
testacea, the authenticated examples of imbedded re- 
gains of terrestrial mammalia are extremely scanty ; 
^^d several of those which have been cited by earlier 
'^I'iters 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 

r 

0^ ten instances, perhaps, bones of the mastodon, rhi- 
^ocerosj 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- 

P- 190. Pratt, Geol. Trans. 2nd series, vol. iii. p. 451. 
i830. 



Read, 



"VOL. I. 



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242 



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 tlie contiguity of land inhabited by large 
herbivora, which renders the rarity of such exceptions 
more worthy of attention. On the 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 an 
inland lake, surrounded by lofty mountains.* 

Not a single bone of any quadrumanous animal has 
ever yet been discovered in a fossil state ; and their 
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 order 
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 maj 
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 character 
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 
rhmoceros, tapir, hippopotamus, ox, deer, pig, and 
others. Species which live in trees are extremely 
rare m a fossil state ; and we have no data as yet for 
determining liow great a number of the one kind v^e 






* 



See Book iv. ch, xvi. 






Ch. IX.] 



PROGRESSIVE DEVELOPMENT. 



243 



+ 

ought to find, before we have a right to expect a single 
individual of the other. Even therefore, if we were 
^ed 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- 
dmmanous tribe,' we nevertheless could not hope 
to discover any of then' skeletons until we had made 
Considerable progress in ascertaining what were 
tile contemporary Pachydermata ; and a very small 
number of these have, as was before remarked, been 
hitherto discovered in any strata of this epoch in 
Endand. 



ri^ 



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 
Regard 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- 
elusions, 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 ; 
out, 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 
^^ght : it is therefore superfluous to pursue this part of 
the argument farther. 

If we then examine the animal remains of the oldest 



for 



nations, we find bones and skeletons of fish in 



the old red sandstones, and even in some transition 



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244^ 



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. 



245 



^sked, whether the recent origin of man lends any sup- 
port to the same doctrine, or how far the influence of 
^an 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- 
I'ienced 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, 
now 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 
^orks, 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 
^ost 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 
liistorical 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 
oones of large beasts of prey occur in abundance; and 
they indicate that^ at periods comparatively modern in 
the history of the globe, the ascendancy of man^ ir he 
existed at all, had scarcely been felt by the brutes.* 

■t 

Respecting the probable antiquity assignable to certain human 

M 3 



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246 



UNIFORMITY OF THE SYSTEM. 



[Book L 



No inhabitant of the land exposes himself to so 
many dangers on the waters as man, whether 



m 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, f 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- 
strdctible materials, would have outlasted almost all 
the organic contents 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, t 

Dr. Prichard has argued that the human race have 



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. 



t Ibid. 









r 



»'■■ 



1 >■■' 
■ 4- 






Ch. IX.] 



RECENT ORIGIN OF MAN. 



247 



^ot always existed on the surface of the earth, because 
*' the strata of which our continents are composed 
^ere once a part of the ocean's bed" — " mankind had 
a beginning, since we can look back to the period 
^hen the surface on which they Uved began to exist."* 
"^his 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 
tbousands of human beings. Nor can this interchange 
of sea and land ever cease while the present causes 
^fe in existence. It is conceivable, therefore, that 
terrestrial species might be older than the continents 
^hich they inhabit, and aquatic species of higher anti- 
quity than the lakes and seas which they people. 

Doctrine of successive development not confirmed hy 
*^e 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- 
*^roduction can be considered as one step in a progres- 
sive system, by which, as some suppose, the organic 
^orld advanced slowly from a more simple to a more 
perfect state ? In reply to this question, it should first 
be observed, that the superiority of man depends not on 
^^ose faculties and attributes which he shares in com- 
mon with the inferior animals, but on his reason, by 



^bich he is distinguished from them. 



When 



that the human race is of far higher dignity than were 
^ny pre-existing beings on the earth, it is the intel- 
lectual and moral attributes only of our race, not the 

* Phys. Hist, of Mankind, vol. ii. p. 594. 



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248 



UNIFORMITY OF THE SYSTEM. 



[Book I. 



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 a 
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 
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 m 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 mhabited for thousands of ages by inferior 
ammals, why should not other changes as extraor- 
dmary 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 



more difficult one 



/ 




•/ 



I 



Ch IX.] 



RECENT ORIGIN OF MAN. 



249 



' r 

epochs? Or what security have we that they may 

r 

^ot arise hereafter? And if such be the case, how 
c^n the experience of one period^ even though we are 
Acquainted with all the possible effects of the then 
existing 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 
l^oth 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- 
^^rred again and again in a perpetual vicissitude, 
^he same individual men were doomed to be re-born, 
And to perform the same actions as before ; the same 
Arts were to be invented, and the same cities built and 
destroyed. The Argonautic expedition was destined 
*-o sail again with the same heroes, and Achilles with 
nis Myrmidons to renew the combat before the walls 



ofTr 



■t 

Alter erit turn Tiphys, et altera quae vehat Argo 

Dilectos heroas : erunt etiam altera bella, 

Atque iterum ad Trojam raagrius mittetur Achilles. 



* Virgil, Eclog. iv. For an account of these doctrines, see 
■^ugald Stewart's Elements of the Philosophy of the Human 



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250 



UNIFORMITY OF THE SYSTE:.L 



[Book I 



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 in 
which we beheve 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 ^ 
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 a 
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 oh 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 Prkhard's Egypt. Mythol 



p. 177. 



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Ch. IX.] 



KECENT ORIGIN OF MAN. 



251 



as 



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 
^riterval, we imagine the state of things to have gone 
^^ according to the order now observed in regions un- 
occupied by man. Even now, the waters of lakes, 
^^as, and the great ocean, which teem with life, may 
^^ said to have no immediate relation to the human 
race — to be portions of the terrestrial system of which 
^an has never taken, nor ever can take, possession ; 
^0 that the greater part of the inhabited surface of the 
planet may remain still as insensible to our presence 
before any isle or continent was appointed to be 

0^^ residence. 

If the barren soil around Sydney had at once become 
fertile upon the landing of our first settlers ; if, like 
^'^e happy isles whereof the poets have given us such 
glowing descriptions, those sandy tracts had begun to 
yield spontaneously an annual supply of grain, we 
'^ight then, indeed, have fancied alterations still more 
^^niarkable in the economy of nature to have attended 
^he first coming of our species into the planet. Or if, 
^hen a volcanic island like Ischia was, for the first 
l^ime, brought under cultivation by the enterprise and 
^^dustry of a Greek colony, the internal fire had 
y^come dormant, and the earthquake had remitted 
^^s destructive violence, there would then have been 
Some ground for speculating on the debilitation of the 
subterranean forces, when the earth was first placed 
^>^der the dominion of man. 

^est, the volcano bursts forth again with renewed 
^^^^gy> annihilates one half of the inhabitants, and 
compels the remainder to emigrate. The course of 
nature remains evidently unchanged; and, in like 

M 6 



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But after a long interval 



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UNIFORMITY OF THE SYSTEM. 



[Book I, 



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 ; a 
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 obejing her laws ; and this prin- 
ciple is true even in regard to the astonishing changes 
which are superinduced in the qualities of certain 
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. 






It II 



I 



Ch. IX.] 



RECENT ORIGIN OF MAN. 



253 



^^ly effect such surprising alterations by assisting the 
^^velopment of certain instincts, or by availing our- 
^^Ives of that mysterious law of their organization, by 
^hich individual peculiarities are transmissible from 
one generation to another.* 

It is probable from these, and many othei- consider- 
ations, that as we enlarge our knowledge of the sys- 
tem, we shall become more and more convinced, that 
t^^e alterations caused by the interference of man 
deviate far less from the analogy of those effected by 
^ther 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 
^f animals and the reasoning power of man; and we 
^^e apt hastily to infer, that the effects of a rational 
^^dan irrational species, considered merely a5/>%5zm/ 
^9mu^ will differ almost as much as the faculties by 
^hich their actions are directed. 

It is not, however, intended that a real departure 
^^om the antecedent course of physical events cannot 
^^ traced in the introduction of man. If that latitude of 
Action which enables the brutes to accommodate them- 
^^Ives in some measure to accidental circumstances, 
could be imagined to have been at any former period 
^^ great, that the operations of instinct were as much 
diversified 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 
established order of things- It might then have been 
^^idj that the earth's becoming at a particular period 
•-he residence of human beings, was an era in the 
^oral, not in the physical world— that our study and 



* 



See Book iii. ch, iii 



t Id. chapters v. vi. vii. and ix. 



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254 



UNIFORMITY OF THE SYSTEM. 



[Book 



I 



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contemplation of the earth, and the laws which govern 
its animate productions, ought no more to be con- 
sidered in the light of a disturbance or deviation from 
the system, than the discovery of the satellites oi 
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 so, 
the earth might be conceived to have become, at a 
certain period, a place of moral discipline, and intel- 
lectual improvement to man, without the slightest 
derangement of a previously existing order of change 
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 

r 

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 rest. Be- 
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 a 
peculiar and unprecedented agency, long after other 
parts of the animate and inanimate world existed, 



I ^ 






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(4! 






) 



/. 



Cli. IX.] 



RECENT ORIGIN OF MAN. 



255 



gencies. 



affords ground for concluding that the experience 
during thousands of ages of all the events which may 
'^^ppen on this globe would not enable a philosopher 
^^ speculate with confidence concerning future con* 
tin 

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 ? 
^ould he no longer be guided in his speculations by 
thestrictestrules of induction ? To these questions it 
*^ay be answered, that, had he previously presumed to 
dogmatize respecting the absolute uniformity of the 
oi^der of nature, he would undoubtedly be checked 
V witnessing this new and unexpected events and 
^ould form a more just estimate of the limited range 
^f his own knowledge, and the unbounded extent of 
the scheme of the universe. But he would soon per- 
^^ive that no one of the fixed and constant laws of the 
^^imate or inanimate world was subverted by human 
Agency, and that the modifications produced w^ere on 
the occurrence of new and extraordinary circumstances, 
^^d those not of a physical but a moral nature. The 
deviation permitted would also appear to be as slight 
^s was consistent with the accomplishment of the new 
^oral 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, 
elapse would take place to the ancient state of 
things ; the domesticated animal, for example 
hovering in a few generations its wild instinct, and the 



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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 no 
right to anticipate any modifications in the results of 
existing causes in time to come, which are not con- 
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. I" 
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 m an indefinite lapse of time, than to causes 
formerly in operation, but which have ceased to act ; 
and if m 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 



f 



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Ch. IX.] 



RECENT ORIGIN OF MAN. 



257 



^hole globe. But should there appear reason to be- 
^^ve that certain agents have, at particular periods of 
P^st time, been more potent instruments of change 
^^Gf the entire surface of the earth than they now 
^^^3 it is still more consistent with analogy to presume, 
^h^t after an interyal of quiescence they will recover 
tbeir pristine vigour, than to imagine that they are 

^'ornout. 

The geologist who assents to the truth of these 
Principles will deem it incumbent on him to examine 
^ith minute attention all the changes now in progress 



^^ the earth, 



and will regard 



every fact collected 



^^spectinfT the causes in diurnal action, as affording 
^^^ a key to the interpretation of some mystery m 
^he archives of remote ages. His estimate of the 
y^lue of geological evidence, and his interest in the 
^^vestigation of the earth's history, will depend en- 
^ii'ely on the degree of confidence which he feels 
1^ regard to the permanency of the great causes of 
change. Their constancy alone will enable him to 
reason from analogy, and to arrive, by a comparison 
^f the state of things at distinct epochs, at the know- 
^^ge of the general laws which govern the economy 

our system. 

The uniformity of the plan being once assumed, 
f^ents which have occurred at the most distant periods 
^^ the animate and inanimate world will be acknow- 
ledged to throw light on each other, and the deficiency 
^f our information respecting some of the most obscure 
P^rts of the present creation will be removed. For as^ 
'^y studying the external configuration of the existing 
^^nd and its inhabitants, we may restore in imagination 
^^e appearance of the ancient continents which have 



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258 



UNIFORMITY OF THE SYSTEM. 



[Book 



I. 



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 
lorms 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 the 
Oowels 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, 
a though we are mere sojourners on the surface of the 
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 
ot mortal eye, but to trace the events of indefinite 
ages before the creation of our race, and Is not even 
withheld from penetrating into the dark secrets of 
the ocean, or the interior of the solid globe ; free, like 
the spirit which the poet described as animating the 



universe, 



ire per omnes 



Terrasque, tractusque maris, ccelumque profundum. 



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259 



BOOK 11. 



CHANGES OF THE INORGANIC WORLD 



Aqueous Causes 



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CHAPTER I. 



B; 



^^i«on of the subject into changes of the organic and inorganic 
^orld — Inorgaaic causes of change divided into aqueous and 
igneous— Aqueous causes first considered — Destroying and 
'^'"ansporting power of running water — Sinuosities of rivers 
"^^0 streams when united do not occupy a bed of double sur- 

face (p, 265.) ■ Heavy matter removed by torrents and floods 

recent inundations in Scotland — EiFects of glaciers and 
icebergs in removing stones — Erosion of chasms through hard 
"■"cks (p. 272.) — Excavations in the lavas of Etna by Sicilian 
rivers— r;-,--o «f tV.P Simeto — Gradual recession of the cata- 



Gorge of the Simeto 



^^cts of Niagara. 



^ 



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Geology was defined to be 



former changes 



^ Science which investigates the 
,"at have taken place in the organic, as well as in the 
"^o*"ganic kingdoms of nature ; and we may next pro- 
^^^'i to inquire what changes are now in progress 
^"^ both these departments. Vicissitudes in the in- 
^^ganic world are most apparent ; and as on them all 

^^tuations in the animate creation must in a great 
J^^easure depend, they may claim our first consideration, 
^e great agents of change in the Inorganic world 
*^^y be divided into two principal classes, the aqueous 
^^d the igneous. To the aqueous belong Rivers, 



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260 



ACTION OF RUNNING "WATER. 



[Book 



II- 



Torrents, Springs, Currents, and Tides ; to the igneous? 
Volcanos and Earthquakes. Both these classes are 
instruments of decay as well as of reproduction ; but 
they may also be regarded as antagonist forces. For 
the aqueous agents are incessantly labouring to reduce 
the inequalities of the earth's surface to a level ; whi'^ 
the igneous are equally active in restoring the uneven- 
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 an 

accurate view of the combined effects of so man/ 

forces in simultaneous operation ; because, when ^'^ 

consider them separately, we cannot easily estimate 

either the extent of their efficacy, or the kind oi 

results which they produce. We are in danger, there' 

fore, when we attempt to examine the influence e^' 

erted singly by each, of overlooking the modifications 

which they produce on one another; and these are 

complicated, that sometimes the igneous and aqueous 

forces co-operate to produce a joint effect, to whic^ 

neither of them unaided by the other could give rise? 

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 the 

interior of the earth to the surface. Sometimes the 

organic combine with the inorganic causes ; as when a 

reef, composed of shells and corals, protects one lii^^ 

of coast from the destroying power of tides or currents? 

and turns them against some other point ; or when 

drift timber, floated into a lake, fills a hollow to whiel^ 



so 







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Ch. I,] 



th 



ACTION OF RUNNING WATER. 



261 



r ^^ 

^ 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- 
atically, endeavouring as much as possible to keep in 
^W that the effects in nature are mixed, and not 
^^■^ple, as they may appear in an artificial arrangement. 

In treating, in the first place, of the aqueous causes^ 
^^ may consider them under two divisions : first, those 
^Wh are connected with the circulation of water from 
^G land to the sea, under which are included all the 
phenomena of rivers and springs ; secondly, those which 
^^ise from the movements of water in lakes, seas, and the 
^^^an, wherein are comprised the phenomena of tides 
^nd currents. In turning our attention to the former 
^^vision, we find that the effects of rivers may be sub- 
^^vided into those of a destroying and those of a re- 
^^^ating nature ; in the destroying are included the 
^^'^sion of rocks, and the transportation of matter to 
^^er levels ; in the renovating class, the formation of 
^^Itas by the influx of sediment, and the shallowing of 

-Action of running water. — I shall begin, then, by 
^escribing the destroying and transporting power of 
^ inning water, as exhibited by torrents and rivers. It 
^ Well known that the lands elevated above the sea 
^^tract, in proportion to their volume and density, a 
^^ger quantity of that ^ aqueous vapour which the 
^^ated atmosphere continually absorbs from the sur- 
^ce of lakes and the ocean. By these means, the 

^gher regions become perpetual reservoirs of water, 
^l^ich descend and irrigate the lower valleys and 
P^^ins, In consequence of this provision, almost all 



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262 



'M ¥ 



DESTROYING AND TRANSPORTING POWER [Book 



II. 



the water is first carried to the highest regions, and i^ 

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 rai» 

had been distributed over the plains and mountain^ 

equally in proportion to their relative areas. AlnioS^ 

all the water is also made by these means to p^^^ 

over the greatest distances which each region afford^' 

before it can regain the sea- The rocks also, in tb^ 

higher regions, are particularly exposed to atn^^' 

spheric influences, to frost, rain, and vapour, and t^ 

great annual alternations of cold and heat, of moisture 

and desiccation. 

Its destroying and transporting power. — Among t^^ 
most powerful agents of decay may be mentioned th^^ 



congelation 



For this reaso^^' 

of 



the 



property of water which causes it to expand duriHo 

so that, when it has penetrated into th^ 
crevices of the most solid rocks, it rends them op 
on freezing with mechanical force, 
although in cold climates the comparative quantity 
rain which falls is very inferior, and although it ^^' 
scends more gradually than in tropical regions, yet 
severity of frost, and the greater inequalities of temps'^' 
ature, compensate in some degree for this diminishe'^ 
source of degradation. The solvent power of wat^"^ 
also is very great, and acts particularly on the cal- 
careous and alkaline elements of stone, especially whei^ 
it holds carbonic acid in solution, which is abundantly 
supplied to almost every large river by springs, ^^^ 
is collected by rain from the atmosphere. The oS^' 
gen of the atmosphere is also gradually absorbed by ^^ 
animal and vegetable productions, and by almost ^ 
mineral masses exposed to the open air. It gradually 



iM 





1 ll 



Ch. I.] 



OF RUNNING: WATER. 



263 



<iestroys the equilibrium of the elements of rocks, and 
tends to reduce into powder, and to render fit for soils, 
^^en the hardest aggregates belonging to our globe.* 

When earthy matter has once been intermixed with 
Running water, anew, mechanical power is obtained by 
*he attrition of sand and pebbles, borne along with 
violence by a stream. Running water charged with 
foreign ingredients being thrown against a rock, ex- 
^^vates it by mechanical force^ sapping and under- 
lining till the superincumbent portion is at length 
Precipitated into the stream. The obstruction causes 
^temporary increase of the water, which then sweeps 
^own the barrier. 



of 



By a repetition of these land- 



^^^ips, the ravine is widened into a small, narrow valley, 
^^ which sinuosities are caused by the deflexion of the 
stream first to one side and then to the other. The 
^^equal hardness of the materials through which the 
^^annel is eroded, tends partly to give new directions 
^^ the lateral force of excavation. When by these, or 
^y accidental shiftings of the alluvial matter in the 
channel, and numerous other causes, the current is 
^^de to cross its general line of descent, it eats out a 
^^rve in the opposite bank, or in the side of the hills 
bounding the valley, from which curve it is turned 
^^^ck again at an equal angle, so that it recrosses the 
^^e of descent, and gradually hollows out another curve 
^^er down in the opposite bank, till the whole sides 
^^ the valley, or river-bed, present a succession of 
^hent and retiring angles. Among the causes of de- 
^^^tion from a straight course by which torrents and 
^^ers tend in mountainous regions to widen the valleys 



1 
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Sir H, Davy, Consolations in Travel, p. 271. 



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TRANSPORTING POWER 



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[Book 



ir. 



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 
diiFerent 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 is 
often restored by the river cutting through the isthmus 
which separates two neighbouring curves. Thus, '^^ 
the annexed diagram, the extreme sinuosity of the- 




river has caused it to return for a brief space in a con- 
trary direction to its main course, so that a peninsula 
is formed, and the isthmus (at a) is consumed on both 
sides by current* flowing in opposite directions. ^^ 
this case an island is soon formed, — on either side of 
which a portion of the stream usually remains. 

Transporting power of water. — In regard to th^ 
transporting power of water, we may often be surprisefl 
at the facility with which streams of a small size, a"'^ 
descending a slight declivity, bear along coarse sao^ 
and gravel ; for we usually estimate the weight ^f 
rocks in air, and do not reflect on their comparative 
buoyancy when submerged in a denser fluid. Th^ 
specific gravity of many rocks is not more than twice 
that of water, and very rarely more than thrice, sO 
that almost all the fragments propelled by a streai» 
have lost a third, and many of them half, of what ^^ 
usually term their weight. 



I 






Ch. I.] 



OF RUNNING WATER. 



265 



I 

ll 



\m 



•I 



i- 



It has been proved by experiment, in contradiction 

r 

to the theories of the earher writers on hydrostatics, to 
"^e a universal law, regulating the motion of running 
^ater, that the velocity at the bottom of the stream is 
^very where less than in any part above it, and is 
greatest 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- 
est and lateral currents is produced by friction ; and 
^hen 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 

— and three feet per second, stones of the size 



* 



gravel,— 
of an egg. 

When this mechanical power of running water is 
Considered, we are prepared for the transportation of 
Wge quantities of gravel, sand, and mud, by the tor- 
ments 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 
^eans they are enabled to convey the whole mass to 



the 



sea. If they had not this removing power, their 



cnannels would be annually choked up, and the valleys 
of the lower country, and plains at the base of moun- 
tain-chains, would be continually strewed over with 
^^agments of rock and sterile sand. But this evil is 
prevented by a general law regulating the conduct of 
dunning water — that two equal streams do not, when 



* Encyc, Brit. — art. Rivers 



VOL. I. 



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256 



TRANSPORTING POWER 



[Book II 



J 

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 

F ' 

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 our 

■ 

* See article Rivers, Encyc. Brit. 



S. 




■7^'- -JIP- 





Ch. Li 



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 
^^om the head of Lochrannoch, one towards Inverness 
^nd 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 
^'hole of their courses were marked by the destruction 
^f bridges, roads, crops, and buildings. Sir 1\ D. 
Lauder has recorded the destruction of thirty-eight 
^ridges, 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 
^ides 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 

^^ches, having upon the whole a water-way of 260 
^^et. The bed of the river, on which the piers rested, 
^as composed of rolled pieces of granite and gneiss^ 
The bridge was built of granite, and had stood un- 
^*^jured for twenty years ; but the different parts were 
^^ept away in succession by the flood, and the whole 
^^ss of masonry disappeared in the bed of the river. 



Mr 



Account of the inundations, " has upon my own pre- 
mises forced a mass of four or five hundred tons of 



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Sir T. D. Lauder's Account of the Great Floods in Moray- 



*ire, Aug. 1829. 



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268 



TRANSPORTING POWER 



[Book n 



the heap 



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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 ; 
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 a 
large block of greenstone-porphyry, weighing nearly 
two tons, and transported it to the distance of a 
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.f 

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. S^l- 
t See a paper by Mr. Culley, F. G. S., Proceedings of Geol. 
Soc. No. 12. 1829. 



* 



t 



i! 



Id 







Ch. I.] 



OF ICEBERGS. 



269 



^hen compared to those of the Alps and other lofty 
chains, and how, during the successive changes which 
^he 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 
now appear most irregular, and should often bear no 
I'elation 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 



In mountainous 



borne along.* 



I'egions 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 

The snov/ 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.f The surface of the moving 
niass 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. 
f Saussure, Voy. dans les Alpes, torn. i. P 

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270 



TRANSPORTING POWER OF 



[Book n 



!i 1 



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 to a 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 ber^s must be 
of great magnitude ; because the mass of ice belo\^ 
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 



i 



Voyage in 1822, p, 233. 



1. 




i 






Ch. I] 



V 



ICEBERGS AND ICE ISLANDS. 



271 



^alleys, mountains, and platforms become strewed 
over with scattered blocks of foreign rock, of a nature 
perfectly dissimilar from all in the vicinity, and which 
^ay have been transported across unfathomable 
abysses. We have before stated, that some ice islands 
^ave been known to drift from Baffin's Bay to the 
Azores, and from the South Pole to the immediate 
Neighbourhood 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 
^p, 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, f 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 iip into floating islands. 



Excavation of 



The ra- 



pidity with which even the smallest streams hollow 
out deep channels in soft and destructible soils is re- 
niarkably 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. 

f Consid, sur les Blocs Errat, 1829. 

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272 



EROSION OF RAVINES. 



[Book II. 



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 
Atno del Cavallo cut, in three dajs, 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 width. 
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 oi loose 

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. 

Becent excavation hy the Simeto.—V>xxt 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 



which 



scoriae, out 



of 



* 



( 



See Bookiv. ch, 19. 



. . . (^ 



H 



I 





Ch. I] 



LAVA EXCAVATED BY THE SIMETO. 



273 



of the great volcano, has flowed to the distance of five 
•^1* six miles, and then reached the alluvial plain of the 



Fig. 8- 




Recent excavation of lava at the foot of Etna hy the river Simeto. 

r" 

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 
^s 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 
01* 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 
^ 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 
ov scoriaceous, but consists of a compact homogeneous 
'^ass of hard blue rock, somewhat inferior in weight to 

* 

* Quadro Istorico delF Etna, 1824. Some doubts are enter- 
tained as to the exact date of this current by others, but all agree 
^hat it is not one of the older streams even of the historical era. 

-r- 

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:et 



[Book n 



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 in 
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 in 
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 a 
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- 



I 



J^ ^ L ._ 







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 
<>f 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 Niaga\ 



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 
^pper 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 on the East. * The river, where it 
issues, is about three quarters of a mile in width. 
Before reaching the falls, it is propelled with great 
I'apidity, 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 



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Captain Hairs Travels In North America, voL i« P- 179 

N 6 




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276 



FALLS OF NIAGARA. 



[Book IL' 



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.-j- This is not improbable ; and 



* Hall's Travels in North America, vol, i. pp. 195, 196. 216- 

f See Mr. Bakewell, jun. on the falls of Niagara, with two 

descriptive drawings of the couqtry between Lakes Erie and 






^ 



"1 





-J-^T T.^ 



^ ^ 




Ch. I.] 



FALLS OF NIAGARA. 



277 



ri J 



^e 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 
J'lver below the falls is strewed over with huge frag- 
ments which have been hurled down into the abyss. 
% the continued destruction of the rocks, the falls 
We, within the last forty years, receded nearly fifty 
y^rds, or, in other words, the ravine has been prolonged 
to that extent. Through this deep chasm, the Niagara 
flows for about seven miles ; and then the table-land, 
^hich is almost on a level with Lake Erie, suddenly 
^inks down at a town called Queenstown, and the river 
^merges from the ravine into a plain, which continues 
to the shores of Lake Ontario. 

Kecession 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 
ti'om 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 
mrmations as are now exposed to view at the falls. The 
^Pper stratum is an ancient alluvial sand, varying in 
thickness from 10 to 140 feet ; below which is a bed 
^f hard limestone, about ninety feet in thickness, 
stretching nearly in a horizontal direction over the 
^hole country, and forming the bed of the river above 
the fallsj as do the inferior shales helow. The lower 
Shale is nearly of the same thickness as the limestone ; 
"^t this last is said to thicken at the point now reached 
^y the falls, a circumstance which may enable, it in 






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Ontario, including the Falls. — Loudon's Mag. of Nat. Hist 
No. xii. March, 1830. 



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278 



FALLS OF NIAGARA. 



[Book II- 



4 

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 ten 
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 the 
retrograde movement was probably much more rapid 
when the whole current was confined within a space 
not exceeding a fourth or fifth of that which the fall^ 
now occupy. Should the erosive action not be accele- 
rated in future, it will require upwards of thirty thou- 



distant) 



( 



1 



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^ 



i 



I i 



until the period when the ravine recedes to its shores? 
the sudden escape of so vast a body of water migh*' 
cause a tremendous deluge ; for the ravine would b^ 
much more than sufficient to drain the whole lake, ^^ 
which the average depth was found, during the l^^e 
survey, to be only 10 or 12 fathoms. But, in conse- 
quence of its shallowness. Lake Erie is fast filling ^? 
with sediment ; and it may be questioned, whether its 
entire area may not be converted into dry land, before 
the falls recede so far. 

Monthly American Journ. July, 1831, p. 2L 



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279 




CHAPTER IL 



hH 



\\ 



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 — Raftofthe Atchafalaya'(p. 286.) — Driftwood — 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. 



bourse of the Po. — :The Po affords an instructive 
example of the manner in which a great river bears 
*iown to the sea the matter poured into it by a multi- 
tude of tributaries descending from lofty chains of 
fountains. The changes gradually effected in the 
great plain of Northern Italy, since the time of the 
I^oman republic, are considerable. Extensive lakes 
^^d marshes have been gradually filled up, as those 
^ear Placentia, Parma, and Cremona, and many have 
^^en drained naturally by the deepening of the beds 
of rivers. Deserted river-courses are not unfrequent, 

r X 

^s that of the Serio Morto, which formerly fell into 
*'^e Adda, in Lombardy ; and the Po itself has often 
deviated from its course. Subsequently to the year 
^390, it deserted part of the territory of CremonRj 
^nd invaded that of Parma ; its old channel being still 
i^ecognizable, and bearing the name of Po Morto. 
^ressello is one of the towns of which the site was 



for 



merly on the left of the Po, but which is now on 



I !■ 



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4 




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p IJ 



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II 



I 



1 



w 



280 



EMBANKMENTS OF PO AND ADIGE. 



[Book n 



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 I47I5 demolished their build- 
ings, and reconstructed them at Fontana, whither they 
had transported the materials. In like manner, the 
church of S. Rocco was demolished in 1511. In the 
seventeenth century also the Po shifted its course for 
a mile in the same district, causing great devastations 



Artificial embankments of 



To check 



these and similar aberrations, a general system of 
embankment has been adopted ; and the Po, Adig^? 
and almost all their tributaries, are now confined^ 
between high artificial banks. The increased velocity 
acquired by streams thus closed in, enables them to 
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 Adriatic 
since the practice of embankment became almost 
universal. But, although more sediment is borne to 
the sea, part of the sand and mud, which in the 



i>, 



rt 



I 



* 



Deir Antico Corso de' Fiumi Po, Oglio, ed Adda, dell' Gio- 



yanni Romani. Milan^ 1828, 



n 



] 
* 






. ^ 






ili 



^^- 11.] 



BASIN OF THE MISSISSIPPI. 



281 



plain 



^^tural state of things would be spread out by annual 
inundations over the plain, now subsides in the bottom 
^* the river-channels ; and their capacity being thereby 
^^^inished, it is necessary, in order to prevent in- 
undations in the following spring, to extract matter 

^^in the bed, and to add it to the banks, of the river, 
^^nce it happens that these streams now traverse the 

on the top of high mounds, like the waters of 
^^^educts, and at Ferrara the surface of the Po has 
^^come more elevated than the roofs of the houses.* 
"^ne magnitude of these barriers is a subject of in- 

^^asing expense and anxiety, it having been some- 

^n^es found necessary to give an additional height of 
^^arly one foot to the banks of the Adige and Po in a 

^ngle season. 
The practice of embankment was adopted on some 
the Italian rivers as early as the thirteenth century ; 

^d Dante, writing in the beginning of the fourteenth, 
^scribes^ in the seventh circle of hell^ a rivulet of 

^^^'s separated from a burning sandy desert by em- 

^nkments " like those which, between Ghent and 



B 



^i^ges, were raised against the ocean, or those which 



^^ Paduans had erected along the Brenta to defend 



th 



^ir 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, perche 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 iv 



^asin of the Mississippi. — Thehydrographical basin 
* the Mississippi displays, on the grandest scale, the 



^ 



Prony, see Cuvier, Disc. Prelim, p. 146. 



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282 



BASIN OF THE MISSISSIPPI. 



[Book 



II. 



action of running water on the surface of a vast con- 
tinent. This magnificent river rises nearly in the forty 
ninth parallel of north latitude, and flows to the Gul^ 
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 the 
region of the olive, the fig, and the sugar-cane.* ^^ 
river affords a more striking illustration of the la^ 
before mentioned, that an augmentation of volume doeS 
not occasion a proportional increase of surface, nay> '= 
even sometimes attended with a narrowine of the 



channel. 



Mis 



Missouri + 



of 



^ 



equal width ; yet the united waters have only, froiA 
their confluence to the mouth of the Ohio, a medi^^ 
width of about three quarters of a mile. The junctie'' 
of the Ohio seems also to produce no increase, ^^^ 
rather a decrease, of surface.:}: The St. Francis, Whit^' 
Arkansas, and Red rivers, are also absorbed by th^ 
main stream with scarcely any apparent increase of'^^^ 
width ; and, on arriving near the sea at New Orlean^' 
It is somewhat less than half a mile wide. Its dep*^ 
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 sonie^ 
it does not exceed one mile an hour. 

* Flint's Geography, vol. i. p. 21. 

f Flint says (vol i. p. 140.) that, where the Mississippi receive^ 
the Missouri, it is a mile and a half wide, but, according to Cap- 
tain B. Hall, this is a great mistake. — Travels in North Americ^' 
vol, iii. p. 328. 

J Flint's Geography, vol. i. p. 142. 

§ Hall's Travels in North America, vol. iii. p. 330., who cite* 
Darby. 



h 



.1 









r^l- 



Ch. II.] 



CURVES OF THE MISSISSIPPI. 



283 



The alluvial plain of this great river is bounded 
^^ 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 
^iles broad, and after that point it goes on increasing 
^^ width, till the expanse is perhaps three times as 
g^'eat ! 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, 
^Gver once comes in contact with the western. The 

r 

Waters are thrown to the eastern side, because all the 
^arge tributary rivers entering from the west, have 
filled that side of the great valley with a sloping mass 
^f clay and sand. For this reason, the eastern bluffs 



' ^^e continually undermined, and 



Mississipp 



slowly but incessantly progressing eastward.* 



of the Mississippi 



The river traverses the 



plain in a meandering course, describing immense and 
Uniform curves. After sweeping round the half of a 
^ii^cle, it is carried in a rapid current diagonally across 
^ts own channel, to another curve of the same uni- 
formity upon the opposite shore, t These curves are 
^0 regular, that the boatmen and Indians calculate 
distances by them. Opposite to each of them there 
^s always a sand-bar, answering, in the convexity of 
^ts form, to the concavity of ^^ the bend," as it is 
called. X The river, by continually wearing these 



» 



Geograph. Descrlp. of the State of Louisiana, by W. Darby; 



l^Wladelphia, 1816, p. 102. 
t Flint's Geog. vol. i, p. 152. 



\ Ibid 



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284 



r- 



TRANSPORTATION OF MATTER 



[Book n 



curves deeper, returns, like many other streamfe before 
described, on its own tract, so that a vessel in some 
places, after sailing for twenty-five or thirty miles, is 
brought round again to within a mile of the place 



whence it started. Wh 



the waters approach so 



near to each other, it often happens at high floods 
that they burst through the small tongue of land, and 
msuJate a portion, rushing through what is called the 
" cut off" with great velocity. At one spot, called 
the "grand cut off," vessels now pass from one poin^ 
to another in half a mile to a distance which it formerly 
required a voyage of twenty miles to reach.* 



Waste of 



After the flood season, when 



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 a 
time, thickly covered with wood, are precipitated into 
the stream ; and large portions of the islands formed 
by the process before described are swept away. 

Some years ago," observes Captain Hall, "when 
Mississippi was regularly surveyed, all its islands 
were numbered, from the confluence of the Missouri 
esea; but every season makes such revolutions 



(( 



to th 



not only in the number but 



in the magnitude an' 



d 



situation of these islands, that this enumeration is 
now almost obsolete. Sometimes large islands are 
entirely melted away— at other places they -have 



or. w 



hich IS 



attached themselves to the main shore, 
the more correct statement, the interval has been 
filled up by myriads of logs cemented together by 
mud and rubbish." f When the Mississippi and many 



* Flint's Geog. vol. i. p. 154. 

f Travels in North America,'vol. iii. p. 361 






i 







-^ 



/ 



J^ 



/ 



■> *^ 



/ 



Ch. II.] 



BY THE MISSISSIPPI 



285 



of its great tributaries overflow their banks, the waters, 
being no longer borne down by the main current, and 
becoming impeded amongst the trees and bushes, 
deposit the sediment of mud and sand with which 
^hey are abundantly charged. Islands arrest the pro- 
gress of floating trees, and they often become in this 
banner reunited to the land; the rafts of trees, together 
^ith mud, constituting at length a solid mass. The 
hoarser and more sandy portion is thrown down first 
Nearest the banks ; and finer particles are deposited at 
''he farthest distances from the river, where an im- 
palpable mixture subsides, forming a stiff unctuous 
Wack soil. Hence, in the alluvial plains of these rivers 
'^he land slopes back, like a natural glacis towards the 
Cliffs bounding the great valley (see fig. 9.), and during 



Fig. 9. 




a, Channel of the river. 



b. Base ofthe" bluffs." 



^^^undations the highest part of the banks form narrow 
strips of dry ground, rising above the river on one 
^'de, and above the low flooded country on the other, 
fhe Mississippi therefore has been described as a 
^iver running on the top of a long hill or ridge, which 
has an elevation of twenty-four feet in its highest part, 
^^d a base three miles in average diameter. Flint, 
however, remarks, that this picture is not very cor- 
^^et, for, notwithstanding the comparative elevation of 

e banks, the deepest part of the bed of the river 
(^5 fig. 9.) is uniformly lower than the lowest point of 
^he alluvium at the base of the bluffs.* 

It has been said of a mountain torrent that " it lays 
^own what it will remove, and removes what it has 
^^id down;" and in like manner the Mississippi? by the 



th 



* 



Flint's Geography, vol. i, p. 151 



{W 



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286 



RAFT OF THE ATCHAFALAYA, 



[Book n* 



continual shifting of its course, sweeps away, during a 
great portion of the year, considerable tracts of alluvium 
which were gradually accumulated by the overflow o( 
former years, and the matter now left during the spring- 
floods will be at some future time removed. 

Haft 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, ^"^^ 
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 main 
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 ; in 
some parts of its course, cedar trees are heaped up by 
themselves, and in other places pines. There is also 
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 forest 



not excepting large trees ; and so perfectly was the 
stream concealed by the superincumbent mass, that it 






U. 



tt^ 



J * L 





^h. II.] 



DRIFT WOOD. 



287 



^^ght be crossed in some places without any knowledge 
^^ its existence * 

J^rift Wood. — Notwithstanding the astonishing 

dumber of cubic feet of timber arrested by the rafts, 

S^eat deposits are unceasingly in progress at the ex- 

^^emity of the delta in the Bay of Mexico. " Unfor- 

^^ately for the navigation of the Mississippi," observes 

^ptain Hall, " some of the largest trunks, after being 

^^t down from the position on which they grew, get 

^eir roots entangled with the bottom of the river, 

J^ere they remain anchored, as it were, in the mud. 

^^ force of the current naturally gives their tops a 

^dency downwards, and, by its flowing past, soon 

J'^ps them of their leaves and branches- These 

^^Ures, called snags or planters, are extremely dan- 

r^'^us to the steam-vessels proceeding up the stream, 

^nich they lie like a lance in rest, concealed be- 

^th the water, with their sharp ends pointed directly 
^^^nst the bow of the vessels coming up. For the 
/^^t part, these formidable snags remain so stilly that 
^y can be detected only by a slight ripple above 

^^3 not perceptible to inexperienced eyes. Some-. 

/^^s, however, they vibrate up and down, alternately 

^Wing their heads above the surface and bathing 

, ^ beneath it/'f So imminent is the danger caused 

/ ^hese obstructions, that almost all the boats on the 

^ssisslppi are constructed on a particular plan, to 
^^^rd against fatal accidents. |: 

Navigator, p. 263. Pittsburgh, 1821. 

travels in North America, vol. iii. p. 362, 

Call ^OBt^ are fitted," says Captain Hall, " with what is 

ij ^ snag-chamber; — a partition formed of stout planks, which 

^nd ^ ' ^^^ ^^^^ so effectually water-tight, that the foremost 

of the vessel is cut off as entirely from the rest of the hold ast 



mm 




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288 



DRIFT WOOD OF .THE MISSISSIPPI. 



[Book 



II. 



of 



:. The prodigious quantity of wood annually drifted 
down by the Mississippi and its tributaries, is a subject 
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 th^ 
constant destruction of soil and transportation of nia^^ 
ter to lower levels by the tendency of rivers to sh\^^ 
their courses. Each of these trees must have require^ 
many years, some. of them many centuries, to attai^^ 
their full size ; the soil, therefore, whereon they gi'^^^ 
after remaining undisturbed for long periods, is uH^' 
mately torn up and swept away. Yet, nofwithstai^*^' 
ing this incessant destruction of land and up-rooting 
trees, the region which yields this never-faiiing supp'/ 
of drift wood is densely clothed with noble forest^ 
and is almost unrivalled in its power of supporti^^ 
animal and vegetable life. 

Innumerable herds of wild deer and bisons feed ^^ 
the luxurious pastures of the plains. The jaguar, t^^ 
wolf, and the fox, are amongst the beasts of prey. "^^^ 
waters teem with alHgators and tortoises, and tb^^^ 
surface is covered with millions of migratory wat^'*^ 
fowl, which perform their annual voyage between t^^ 
Canadian lakes and the shores of the Mexican G^'^' 
The power of man begins to be sensibly felt, and t^^ 
wilderness to be replaced by towns, orchards, ^^^ 
gardens. The gilded steam-boat, like a moving <^^^^' 
now stems the current with a steady peace— i^^^ 



7 






if it belonged to another boat. If the steam-vessel happen to 
against a snag, and that a hole is made in her bow, under the 
face, this chamber merely fi Us with water.*' Travels in ^^^^ 
America, vol. iii. p. 363. 






I 



' -i*.fc - 



u» 






Ch. II.] 



DRIFT WOOD OF THE MISSISSIPPI. 



289 



mal 



shoots rapidly down the descending stream through 
the solitudes of the forests and prairies. Already 
^oes 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- 
guinary struggle, were severed from the parent 
Country.* Such is the state of a continent where 
^ocks 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- 
^^nt 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- 
> ; but, on the contrary, the ocean here swarms 
^'ith life, as it generally does where the influx of a 
S^eat 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, 
^^lagine that they ai'e viewing the signs of a turbulent 
^^stead of a tranquil and settled state of the planet. 
A hey 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 
^^^d fertile districts now tenanted by man. They are 
^ot content with disregarding the analogy of the 
Present course of Nature, when they speculate on the 
^^volutions 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. 



O 



i: 



I 11 



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290 



NEW LAKES IN LOUISIANA. 



I 



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8 



[Book IT 



Formation of 



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 under 
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^ ^^ 
which the alluvial accumulations have been so great 
as to raise its channel, and cause its waters, during 
the flood season, to ^ow 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 agaiii 
depressed, the waters rush back again, and some lakes 
become grassy meadows, with streams meandering 
through them.f 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 North 
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. 



1 




— -Hb 



.^ 





.i^v 



Ch. II.] 



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, 
tbat a bar has been thrown by Red River across some 
^f the openings of these channels, and then the lakes 
"ecome, like Bistineau, constant repositories of water. 
^^t even in these cases, their level is liable to annual 
elevation and depression, because the flood of the main 
^iver, when at its height, passes over the bar ; just as, 
^here 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- 
^^ted again the interior. 

The frequent 



of Mississippi, 
fluctuations in river courses, in various parts of the 

Mississippi, are partly, perhaps, to be 



b 



^Scribed to the co-operation of subterranean move- 
^^ents, which alter from time to time the relative 
levels of various parts of the surface. So late as the 
J'ear 1812, the whole valley from the mouth of the 
^hio to that of the St. Francis, including a tract three 
hundred miles in length, and exceeding in area the 
^hole basin of the Thames, was convulsed to such a 
^^gree, as to create new islands in the river, and Jakes 
^^ the alluvial plain, some of which were twenty miles 
^^extent. I shall allude to this event, by which New 
Madrid was in great part destroyed, when I treat of 
^^I'thquakes ; but may state here, that it happened 
^^actly at the same time as the fatal convulsions in the 
^strict of Caraccas; and the country shaken was 
early five degrees of latitude farther removed from 
^^ great centre of volcanic disturbance, than the 

^^sin of the Red River before alluded to. Darby 



X 



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292 



FLOODS, BURSTING OF LAKES, ETC. 



[Book 



II. 



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 oi 
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 as 
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 the 
lapse of ages, in widening and deepening a valley, does 
not so much depend on the volume and velocity of the 
Stream usually flowing in it, as on the number and 
magnitude of the obstructions which have, at different 
periods, opposed its free passage. If a torrent, ho^" 
ever small, be effectually dammed up, the size of the 
valley above the barrier, and its declivity below, and 
not the dimensions of the torrent, will determine the 
violence of the debacle. The most universal source ot 
local deluges are landslips, slides, or avalanches, as 
f hey are sometimes called, when great masses of r^^ 






p 



1 





I ' 



I I 



Ch. IL] 



FLOODS IN NORTH AMERICA. 



293 



^nd 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, 
w undermined by springs or other causes. Volumes 
^ight 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- 

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- 
nient, 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, 
^as 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- 
hollow 



One of these moving masses 



came vast chasms. At the base of th 
Ravines was seen a wide and deep mass of rums, 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, 
^here they disputed the ground, the torrent of mud 
and rock accumulated behind till it gathered sufficient 
force to burst the temporary barrier. 

o 3 



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294 



FLOODS IN NORTH AMERICA. 



[Book n. 



cattle were 



W 



The valleys of the Amonoosuckand 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 

llej^ family, nine 
in number, who in alarm had deserted their house, 
were destroyed on the banks of the Saco ; seven o? 
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 o( 
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 

fossd rehcs to be principally referable to this class o( 
mammalia. 

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 



> ri 



• Silliman's Journal, vol. xv. No. 2. p. 216. Jan. 1829. 





^x 



Ch. II.] 



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 caused by the bursting of a 
temporary lake ; the facts having been described, with 
more than usual accuracy, by scientific observers 



Flood ifi the Valley of 



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 

elevated glacier into the bed of the river 
In the winter season, during continued frost, 



fro 
Dra 



m an 



nse. 



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 

an artificial gallery, seven hundred feet in 



b 



arrier. 



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 
residue of the lake was emptied In half an hour. 

of its descent, the waters encountered 



and the 

In 



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296 



BURSTING OF A LAKE 



[Book n. 



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 m circumference.* The velocity of the water, 
m 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 



t 



Martigny 



thousands of trees torn up by the roots, together with 
the rums of buildings. Some of the houses in that 
town were filled with mud up to the second story. 



Martigny 



the Rhone and did no further damage; but 



some 



Mart 



were afterwards found, at the distance of about thirty 
miles, floating on the farther side of the Lake of 
(jreneva, near Vevey. 

^ The waters, on escaping from the temporary lake, 
intermixed with mud and rock, swept alongf 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. is7., drawn up from the 

Memoir of M. Escher, with a section, &c. 






I 







Ch. 11.3 



IN THE VALLEY OF BAGNES. 



297 



M 



not 



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- 
vating force which a river may have exerted in any 
particular valley, the most important question is, 
the volume of the existing stream, nor the present 
levels of its channel, nor even the nature of the rocks, 
hut the probability of a succession of floods, at some 
period since the time when the valley may have been 

fi^st elevated above the sea. 
For several months after the debacle of 1818p the 

I^ranse, having no settled channel, shifted its position 
Continually from one side to the other of the valley, 
carrying away newly erected bridges, undermining 
houses, 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 
hridge, and the undermining of part of a house. The 
gi'eater 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 

intersected 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, 
^nd the waters, descending with irresistible fury, de- 
stroyed the town of Martigny, where from sixty to 

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298 



FLOOD OF THE ANIO AT TIVOL 



Book n. 



eighty persons perished. In a similar flood, fifty 
years before, 140 persons were drowned. 



Flood 



I shall conclude with one 



more example, derived from a land of classic recoUec- ^ 
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 
Tivoh, which were all carried away, presenting, as 
they sank into the roaring flood, a terrific scene of 
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. II.] 



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 



t 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. 

t Illustr. of Hutt. Theory, § 3. p. 147. 

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300 



CHAPTER HI. 



PHENOMENA OF SPRINGS. 



Origin of Springs — Bored wells - Distinct causes by which 
mineral and thermal waters may be raised lo the surface 
Their connection with volcanic agency (p. 308.) — Calcareous 



Springs _ Travertin of the Elsa 
of San Filippo, near Radicofani 



Baths of San Vignone and 
Spheroidal structure in tra- 



vertin, as in English magnesian limestone (p. 317.) 
of Viterbo 



Bulicami 



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. 

Oriffin of springs The 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 famihar 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 
approachmg 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 
mto any opening which may be made, in the same 
manner as we see the salt water flow into, and fill, 



i 

r 

\ 








Ch. 111.] 



ORIGIN or SPRINGS. 



301 



^^y hollow which we dig in the sands of the shore at 
W tide. 

The facility with which water can percolate loose 
^nd gravelly soils is clearly illustrated by the effect of 
^he tides in the Thames between Richmond and 

The river, in this part of its course, flows 
through a bed of gravel overlying clay, and the porous 
^^perstratum is alternately saturated by the water of 
the Thames as the tide rises, and then drained again 
^^ the distance of several hundred feet from the banks 
^hen the tide falls, so that the wells in this tract regu- 



L 



ow. 



^^% ebb and fl 

If the transmission of water through a porous 
Medium be so rapid, we cannot be surprised that 
^Pnngs should be thrown out on the side of a hill^ 

ere the upper set of strata consist of chalk, sand, or 



^h 

^ther permeable substances, while the subjacent are 

^^niposed of clay or other retentive soils. The only 

^^fficulty, indeed, is, to explain, why the water does 

^^t ooze out every where along the line of junction of 

*he two formations, so as to form one continuous land- 

^oak, instead of a few springs only, and these far dis- 

^^t from each other. The principal cause of this 

^iicentration of the waters at a few points is, first, the 

^equency of rents and fissures, which act as natural 

^^ains ; secondly the existence of inequalities in the 

^Pper surface of the impermeable stratum, which lead 

tK 
"e 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 
'^^guid, or entirely cease to flow, after long droughts, 
^^d are again replenished after a continuance of rain, 
^any of them are probably indebted for the constancy 



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302 



ORIGIN OF SPRINGS. 



[Book 



IT. 



and uniformity of their volume to the great extent of 
the subterranean reservoirs with which they comiu^" 
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 degree? 
in every great lake which is not sensibly affected ii' 
its level by sudden showers, but only slightly raised; 
so that its channel of efflux, instead of being swol^ 
suddenly like the bed of a torrent, is enabled to carry 
off the surplus water gradually. 



i^ 



Much 



the 



the 



theory of springs, by the boring of what are called by 
the French " Artesian wells," because the method ha? 
long been known and practised in Artois ; and it '^ 
now demonstrated that there are sheets, and, in soi»^ 
places, currents of fresh water, at various depths in 
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 rocl^ 
is met with, it is first triturated by an iron rod, an^ 
the materials, being thus reduced to small fragment? 
or powder, are readily extracted. To hinder the side? 
of the well from falling in, as also to prevent t^^ 
spreading of the ascending water in the surrounding 
soil, a jointed pipe is introduced, formed of wood i» 
•Artois, but in other countries more commonly of metal- 
It frequently happens that, after passing through hun- 
dreds of feet of retentive soils, a water-bearing stratum 
is at length pierced, when the fluid immediately ascend? 
to the surface and flows over. The first rush of the 
water up the tube is often violent, so that for a tin^^ 
the water plays like a fountain, and then, sinking, con- 
tinues to ^ow over tranquilly, or sometimes remains sta- 
tionary at a certain depth below the orifice of the well- 



J 




I 






Ch. III.] 



ORIGIN OF SPRINGS. 



303 



This spouting of the water in the first instance is pro- 
bably owing to the disengagement of air and carbonic 
^cid P:as, for both of these have been seen to bubble 
^p with the water * ■ 

At Sheerness, at the mouth of the Thames, a well 
^as 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 atFulham, 
^ear 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 
elay and loam, and 67 feet of chalk, and the water then 
^ose to the surface from a depth of 329 feet. + At the 
r^uke of Northumberland's, above Chiswick, the borings 
^ere 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 H^ricart de Thury's work on " Puits Fores, 
t Sabine, Joura. of Sci., No. 33. p. 72. 1824. 



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ORIGIN OF SPRINGS. 



[Book n. 



•? 



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, io 
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, f 

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. X 

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. Br 

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 oi 

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 a a, rest on 
the impermeable rock d, and be covered by another 
mass of an impermeable nature. The whole mass a a 
may easily, in such a position, become saturated with 

^ * Hericart de Thury, p. 49- 

t Bull, de la Soc. G^ol. de France, torn. iii. p. 194. 
\ Id. torn. ii. p. 272. 

§ Boue, Resume des Prog, de la Geol. en 1832, p. 184. 
II Bull, de la Soc. Geol. de France, torn. ii. p. 364. 



\ 





i. ^ 



1 

i 



^1 






^ 



^^- III.] 



ORIGIN OF SPRINGS. 



305 



^ater, which may descend from its higher and exposed 
parts — a hilly region to which clouds are attracted, 



Fig. 10. 




1 



^^d where rain falls in abundance. Suppose that at 
^orne point, as at b, an opening be made which gives 
^free passage upwards to the waters confined in a a 
^^ so low a level that they are subjected to the pres- 
^^re of a considerable column of water collected in 

*^G more elevated portion of the same stratum. The 
^ater will then rush outj just as the liquid from a 

^^ge barrel which is tapped, and it will rise to a 
^^ight corresponding to the level of its point of de- 
parture, or, rather, to a height which balances the pres- 
^Ure previously exerted by the confined waters against 
^lie roof and sides of the stratum or reservoir a a. In 
^ke 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, 

^ may mention those numerous rents and faults 

'^ich abound in some rocks, and the deep ravines 

and valleys by which many countries are traversed ; 

^^j when these natural lines of drainage exist, there 
^^^^ains a small quantity only of water to escape by 
^^tificial issues. We are also liable to be baffled by the 
S^'^at thickness either of porous or impervious strata, 
^^ by the dip of the beds, which may carry off the 
Waters from adjoining high lands, to some trough in an 



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ORIGIN OF SPRINGS. 



[Book 



II. 



eat 



opposite direction ; as when the borings are made at 
the foot of an escarpment where the strata incline 

inwards, or in a direction opposite to the face of the 
chffs. 

The mere distance of hills or mountains need not 
discourage us from making trials ; for the waters which 
tall on these higher lands readily penetrate to gr 
depths through highly inclined or vertical strata, or 
through the fissures of shattered rocks, and after Boe- 
ing for a great distance, must often re-ascend and be 
brought up again by other fissures, so as to approad^ 
the surface in the lower country. Here they mayb^ 
concealed beneath a covering of undisturbed horizontal 
beds, which it may be necessary to pierce in order to 
reach them. It should be remembered, that the cours« 
of waters flowing under ground bears but a remote 
resemblance to that of rivers on the surface, there 
being, in the one case, a constant descent from a highe^ 
to a lower level from the source of the stream to the 
sea ; whereas, in the other, the water may at one tiw^ 
smk far below the level of the ocean, and afterwar^^ 
rise again high above it. 

Among other curious facts ascertained by aid of 
the borer, it is proved that in strata of different age^ 
and compositions there are often open passages M 
which the subterranean waters circulate. Thus, ^' 
bt. Ouen, in France, five distinct sheets of water were 
intersected in a well, and from each of these a suppl/ 



obtamed. In the third water-bearing stratum, "■ 
the depth of 150 feet, a cavity was found in which 
the borer fell suddenly about a foot, and thence the 
water ascended in great volume * The same falling o^ 



* 



H. de Thury, p. 295. * 










Ch. HI.] 



ORIGIN OF SPRINGS. 



307 



1 



^^e instrument, as in a hollow space, has been remarked 
^n England and other countries. At Tours, in 1830, 
^ Well was perforated quite through the chalk, when 
^he 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 
Qng, much blackened by their stay m the water, were 
Recognized, as also the stems of marsh plants, and 
^<^tne of their roots, which were still white, together 
^^ith the seeds of the same, in a state of preservation 
^^hich showed that they had not remained more than 
^hree or four months in the water, 
^ere those of the marsh-plant Galium uliginosum; 
^^d among the shells, a freshwater species {Planorhis 



Among the seeds 



Helix 



H. 



M 



^ei'ved this phenomenon, supposes that the waters had 
flowed from some valleys of Auvergne or the Vivarais 
^^iice the preceding autumn.* 

An analogous phenomenon is recorded at Riemke, 
^ear Bochum in Westphalia, where the water of an 
^^tesian 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 

'^agues.f 

In both cases it is evident that water had pene- 
^^ated to great depths, not simply by filtering through 
^ porous mass, for then it would have left behind the 
^^iells, fish, and fragments of plants, but by flowing 
through some open channels in the earth. Such ex- 
^'^ples may suggest the idea that the leaky beds of 
divers are often the feeders of springs. 

* Bull, de la Soc. Geol. de France, torn. i. P- 95. 

t Id. p. 248. 



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308 



MINERAL AND 



[Book H' 






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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 



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 
ram-water. But the springs called mineral contain an 
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 where 
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 
unceasmgly for ages. Now, if such columns of steam, 
which are often mixed with other gases, should be 
condensed before reaching the surface, by coming i" 
contact with strata filled with cold water, they ra&f 
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 can 
account for the rise of such bodies of water from great 



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Ch. III.] 



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- 
nication 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 
yve include earthquakes among the eflFects 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 
nature, 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, 



11 



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310 



MINERAL SPRINGS. 



[Book It 



be insurmountable, if we believed that all the atmo- 
pheric 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 ocean, 
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, an(J 
farthest from it in those districts which have been 
longest fre6 from eruptions or earthquakes; but to 
pursue this inquiry farther would lead us to antici- 
pate many topics belonging to another division of our 
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 



L 



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I I 



Ch. III.] 



CALCAREOUS SPRINGS. 



311 



^^I'th to the habitable surface, are of a nature and in a 
wm which adapts them peculiarly for the nutrition of 
^inials and plants. 

As these springs derive their chief importance to 
^he geologist from the quantity and quality of the 
^^i^thy materials which, like volcanos, they convey 
ft'om below upwards, they may properly be considered- 
^^ reference to the ingredients which they hold in 
^^lution. These consist of a great variety of sub- 
stances ; but the most predominant are, carbonate of 
*^*^e, carbonic and sulphuric acids, iron, silica, mag- 
^^sia, alumine, and salt, besides petroleum, or liquid 
^^tumen, and its various modifications, such as mineral 
pitch, naptha, and asphaltum. 

Calcareous springs. — Our first attention is naturally 
^ii'ected to springs which are highly charged with cal- 
^^reous matter ; for these produce a variety of phe- 
nomena of much interest in geology. It is known that 
^^in-water has the property of dissolving the calcareous 
^ocks over which it flows, and thus, in the smallest 

ponds and rivulets, matter is often supplied for the 
Earthy secretions of testacea, and for the growth of 
^^rtain plants on which they feed. But many springs 
Wd so much carbonic acid in solution, that they are 
Enabled to dissolve a much larger quantity of cal- 
^^reous matter than rain-water ; and when the acid is 
dissipated in the atmosphere, the mineral ingredients 
^e thrown down, in the form of tufa or travertin.* 

Auvergne. — Calcareous springs, although mostabun- 
^^nt in limestone districts, are by no means confined 



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* The more loose and porous rock, usually containing incrusted 
plants and other substances, is called tufa ; the more compact, 
^^•avertin. See Glossary, ' Tufa, ' < Travertin,' end of Vol. I. 



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312 



CALCAREOUS SPRINGS. 



[Book 11 



I 



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to them, but Aow 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, or 
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 a 
gneiss country, at the foot of a regular volcanic cone, 
at least twenty miles from any calcareous rock. Some 
masses of tufaceous deposit, produced by this spring? 
have an oolitic texture. 

Valiei/ of the Elsa — If we pass from the volcanic 
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 hollo^ 
beneath the foot. 

In other places in the same country, compact rocks 
are seen descending the slanting sides of hills, very 
much m the manner of lava currents, except that the/ 
are of a white colour, and terminate abruptly when 
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. Ill ] 



CALCAREOUS SPRINGS. 



313 



r 

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 Charae, which absorb large quantities 
of carbonate of lime, are very abundant. Carbonic acid 
^s 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 olde^ Apen- 
tiine limestone, shale, and sandstone, while, in other 
places, they flow from more modern deposits ; but 
even in the latter case, their source may probably be 
in or below the older series of strata. 

Baths of Smi Vignone, — Those persons who have 
nierely seen the action of petrifying waters in our own 

r 

eountry, 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 
examples of the rapid precipitation of carbonate of 
We 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. 



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314 



TRAVERTIN 



[Book II- 



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 a 
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. 



Fig. II 




Section of Travertin, San Vignone, 

when not in very small quantity, is of a bright green 
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 angl^ 
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 in 
summer. The rock is generally white ; some parts ot 
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 



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Ch. III.] 



OF SAN VIGNONE. 



315 



, r 

I, 



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 ofFin thin, slightly undulatinglayers. 
A large mass of travertin (c, 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 1 8i^8, 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, bemg 

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, 

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 

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316 



TRAVERTIN OF SAN FILIPPO. 



[Book H. 



; 

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. Th 
rent is broken in its descent by numerous crossed 
sticks, by which the spray is dispersed around upon 
certam moulds, which are l-ubbed 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, f The geologist may 
derive from these experiments considerable light, in 

* Dr. Grosse on the Batbs of San Filippo. Ed. Phil. Journ. 



e cur- 



:' I 



vol. ii. p. 292. 



f Id. p. 297. 



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Ch. Ill] 



SPHEROIDAL TRAVERTIN. 



317 



regard to the high inclination at which some semi- 
crystalUne 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 
i^asses 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 to a 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 
^ater flows, the form of the nucleus being readily 
transmitted through any number of successive enve- 
lopes. But these masses can never be perfect spheres, 

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318 



SPHEROIDAL TRAVERTIN. 



[Book n 



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 in.the 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 laminae.* 

* Geo]. Trans. 2nd series, vol. iii. p. 37. I have lately seen 
some specimens of spheroidal magnesian limestone, collected by 
Professor Sedgwick, where the calcareous lamina are intersected 



\ 




\ 



Ch. III.] 



CALCAREOUS SPRINGS. 



319 



of 



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 Psestum, 
on the Velino at Terni, and in the vicinity of Viterbo. 
About a mile and a half north 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 laminjE 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 eye 
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. 

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320 



CALCAREOUS PRECIPITATES 



[Book II 



ll 



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 Signer 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 ^ew yards above it. The water is a saturated 
solution of carbonic acid gas, which escapes from it in 
such quantities in some parts of its surface, that it has 
the appearance of being actually in ebuUition. " 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 air, 
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, confervae, 
and various kinds of aquatic vegetables ; and at the 
same time that the process of vegetable life is goin_ 
on, the crystallizations of the calcareous matter, which 







Ch. III.] 



OF THE CAMPAGNA DI ROMA. 



S21 



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 confervse : below 
this was a darker and more solid travertin, containing 
black and decomposed masses of conferva; ; in the in- 
ferior part the travertin was more solid, and of a grey 
colour, but with cavities probably produced by the 
decomposition of vegetable matter, f 

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 




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I Id. p. 127. 

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322 



TRAVERTIN OF TIVOLI. 



[Book II 



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 



The waters of the Anio 



mcrust 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 
some of the natural divisions into which they are 
separated by minute variations In the size or colour oi 
the laminae. The undulations also are much smaller, 
m proportion to the whole circumference, than in the 
drawmg The beds a a are of hard travertin and soft 
tufa ; below them is a pisolite (6), the globules being 
of different sizes: underneath this appears a mass oi 



given m 



ark 



concretionary 



( 



being of the above-mentioned extraordinary size. I" 



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hmestone, or tufa, surrounded by concentric layers. 
At the bottom is another bed of pisolite (6), in which 
the small nodules are about the size and shape of 



! 



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Ch. III.] 



TRAVERTIN OF TIVOLT. 



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. ,,^, 



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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 

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324 



TRAVERTIN OF TIVOLT. 



■ [Book II 



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. 
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 sido, they would 
again be set in motion. Sometimes giobules, projecting 
above the general level of a stratum, would attract, by 
cheminal affinity, other matter in the act of precipi- 



Small fragments 



» 



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^1 



Ch. Ill] 



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 
inight 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 thty 
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. 

Calcareous 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, 
^hich 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 
littiestones, 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 
legions between the Caspian and Black Seas, where 
subterranean convulsions are frequent; travellers men- 



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326 



GYPSEOUS SPRINGS, 



[Book n 




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 is 
I quickened by similar causes in the lake of the Solfatara 
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 quan tity of 
I other mineral ingredients wherewith springs in general 
I are impregnated, is insignifiant in comparison to lime, 
and this earth is most frequently combined with car- 
bonic acid. But, as sulphuric acid and sulphuretted 
j hydrogen are very frequently supplied by springs, 
gypsum may, perhaps, be deposited largely in certain 
seas and lakes. The gypseous precipitates, however, 
hitherto known on the land, appear to be confined to a 
very ^ew springs. Those at Baden, near Vienna, which 
feed the public bath, may be cited as examples. Some 
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. 

t C. Prevost, Essai sur la Constitution Physique du Bassin de 
Vienne, p. 10. 



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* Daubeny on Volcanos, p, 222 



Ch. III.] 



SILICEOUS SPRINGS. 



327 



Siliceous springs 



Azoi 



^es. 



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 
^nder the pressure of the sea than in the atmosphere, 
submarine springs may, perhaps, be more charged 
^ith 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 

r 

sprino-j 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 to a 
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 lavers from a quarter to half an inch in thickness, 



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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 scoriae, cemented by siliceous sinter.^ 



of 



But the hot springs in various 



I 



parts of Iceland, particularly the celebrated geysers 
afford the most remarkable example of the deposition 
of silex.f 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 vesicular 
rock is formed, containing portions of vegetables more 

^^^ r 

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, 

f See a cut of the Icelandic geyser, Book IL chap. 19. 



li 



ii^ 



Ch. HI.] 



SILICEOUS SPRINGS. 



329 



ration of the water decomposes the compound of sihca 
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 



Monte 



through which the hot steam passes, are coated with 
a siliceous incrustation, first noticed by Dr. Thompson 

Under the name of fiorite. 

Ava, <^c. — 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 

^eagh, In Ireland. 

the Burman empire, have thrown doubt upon 
lapidifying property of the Ava river t; there is cer- 
tainly no foundation for the story in regard to Lough 
Keagh, 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 

^ -^ AM J-J-^^ —.A ^ .^-^ VA 



Modern 



the 



certain species of corals and sponges with matter for 
their siliceous secretions ; but when in a volcani^ 
archipelago, or a region of submarine volcanos, there 
are springs so saturated with silica as those of Iceland 



Iff 



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Barrow's Iceland, p. 209. 
t Dr. Buckland, Geol. Trans., 2nd series, vol. ii- partm 



p. 384. 



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330 



FERRUGINOUS SPRINGS. 



[Book 



11. 



I 






m 




or the Azores, we may expect layers and nodules o( 
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, ot 
with matter derived from wasting cliffs or volcanic 
ejections. 

Ferrttginous springs. — The waters of almost all 
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 con- 
veyed from the interior of the earth into lakes and seas, 
and which does not escape again from them into the 
atmosphere by evaporation, must act as a colouring 
and cementing principle in the subaqueous deposits 
now in progress. It will be afterwards seen that man/ 
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 in 
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 often 
the solvent, which is in many cases derived from the 
decomposition of pyrites. 

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- 



B 



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Ch. 111.] 



BRINE SPRINGS. 



331 



The 




that of lava. 



Dead 



of Cheshire are the richest in our country; those of 
barton and Northwich being almost and those of 
I^roitwich 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 ongm of the 
Wine, 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 
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 bemg 
frequent products of volcanic eruptions. Many springs 
in 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.f 

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 

I 

* L. Horner, GeoL Trans, vol ii. p. 94. 
t Annales del' Auvergne, tomei. p. 234. 






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332 



CARBONATED SPRINGS. 



[Book H' 



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 i" 
the state of pure gas from the soil in various places- 
Ihe Grotto del Cane, near Naples, aifords an example, 
and prodigious quantities are now annually disengaged 
from every part of the Limagne d'Auvergne, where it 
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 it 
immediately accumulates, so that it will extinguish a 
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- 

™*'r *''!" ^^^^ '^°"^'^ otherwise do in the same soil 

the leaves probably absorbing carbonic 
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- 
^ibaud, not far from Clermont, a rock belono-ing to 
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 
ot iron, Jime, and manganese are so dissolved, that the 
rock IS rendered soft, and the quartz alone remains 

unattacked.t Not far off is the small volcanic cone of 
Chaluzet which once broke up through the gneiss, and 
sent forth a lava-stream. 



and climate 
acid. 



V 



* 



t 



Le Coq, Annalesdel'Auvergne, tomei. p. 217. May, 182S 
Ann. Scient. de 1' Auvergne, tome ii. June, 1 829. 



*11 



^^' III.] 



DISINTEGRATION OF GRANITE. 



333 



^disintegration of granite. — The disintegration of 
S^^nite is a striking feature of large districts in Au- 
^^^gne, especially in the neighbourhood of Clermont, 
^his decay was called by Dolomieu, " la maladie du 



S^^nite;" and the rock may with propriety be said to 
*^^ve the rot, for it crumbles to pieces in tlie hand. 
^he phenomenon may, without doubt, be ascribed to 
^^e continual disengagement of carbonic acid gas from 

^^ftierous fissures. 

In the plains of the Po, between Verona and Parma, 

^^pecially at Villa Franca, south of INIantua, I observed 

§^^at beds of alluvium, consisting chiefly of primary 

Pebbles, percolated by spring water, charged with car- 

^^ate of lime and carbonic acid in great abundance. 

^hey are for the most part incrusted with calc-sinter: 

^d the rounded blocks of gneiss, which have all the 

^tward appearance of solidity, have been so disin- 

^gi'ated by the carbonic acid as readily to 



fall to 



Piec 



es. 



The subtraction of many of the elements of rocks 

y the solvent power of carbonic acid, ascending both 

^ a gaseous state and mixed with spring-water in the 

^^"Gvices of rocks, must be one of the most powerful 

^^I'ces of those internal changes and re-arrangements 

^ particles so often observed in strata of every asre. 

^^ calcareous matter, for example, of shells is often 
^tirely removed and replaced by carbonate of iron, 

^yi'ites, silex, or some other ingredient, such as mine- 
^^ Waters usually contain in solution. It rarely hap- 

P^nSj except in limestone rocks, that the carbonic acid 

^^^ dissolve all the constituent parts of the mass; and 
^^ this reason, probably, calcareous rocks are almost 
^^ only ones in which great caverns and long winding 

passages are found. 



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S34 



PETROLEUM SPRINGS. 



- [Book ll 



Petroleum 



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 those 
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 o( 
the sea, on both sides of the island of Trinidad, and 
to rise up to the surface of the water. Near Cape I^^ 
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 "i^o"^ 
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. partiii. p. 388. 

f Dr. Nugent, Geol. Trans, vol. i. p. 69. 




%\ 



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Ch. III.] 



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 

i 

coarser materials bear an equally strong resemblance 
to the alluvial matter in the beds of existing torrents 

and rivers. 



I 



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* Dr. Nugent, Geol. Trans, vol. i. p. 67 



J^ 










Ii[ m i» 



336 



i- 



CHAPTER IV. 



REPRODUCTIVE EFFECTS OF RUNNING WATER. 



It 



t 



m 



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 Nil® 

(p. 353.) — Its increase since the time of Homer — Its growth 

why checked at present. 



f 

Having 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 o^ 
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. 



i 




I 



Ch. IV.] 



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. 



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Lake of Geneva. — It is natural to begin our examin- 
ation with an inquiry into the new deposits in lakes, 
as they exempHfy 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. 



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II 



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338 



DELTA OF THE RHONE 



[Book 11. 



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 



y 



The 



Hhone, 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. An 



) 



(P 



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 
Vv^e 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. Phi]. Journ. vol. ii. p. 107. Jan. 1820. 
t De la Beche, MS, 



'*"v. 





* De la Beche, MS 

a 2 



Ch. IV.] 



IN THE LAKE OF GENEVA. 



339 



feet 



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 
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- 



\V 



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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 



m 



w 




m- 



,1 







# « 



ch. iva 



OF THE AGE OF DELTAS. 



34^1 



r 

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- 

which it is still gradually eroding to a greater 



riers, 



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 

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 



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342 



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i 



DELTAS OF LAKE SUPERIOR. 



[Book II. 



Villeneuve and Geneva, from two to eight miles in' 

breadth, wh.ch will present no superficial marks of the 

existence of a thickness of more than one thousand 



feet of recent sediment below. 



Many 



tracts of equal, and some of much greater area, may 
be seen if we follow up the Rhone from its termination 
m the Mediterranean, or explore the valleys of many 
of Its principal tributaries. 

r 



Luc, Kirwan, and their followers, who confidently de- 
duced from the phenomena of modern deltas the recent 
ongm of the present form of our continents, without 
pretendmg 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 m 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. 

I^ake ^'uperior. — Lake Superior is the largest body 
of fresh water in the world, being about 1500 geogra- 
phical miles in circumference when we follow the 
smuosities of its coasts, and its length, on a curved 
hne drawn through Its centre, being about 360, and 
Its extreme breadth 140 geographical miles. Its ave- 
rage depth varies from 80 to 150 fathom. _., „. 
cordmg 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. Soc. of Quebec, vol. i. p. 5. 1829. 



s ; but, ac- 




•* 
5 



I 



m 



I 





I 




1 




II 



Hi. IV.l 



DELTAS OF LAKE SUPERIOR. 



34^3 



one 



nearly six hundred feet below the Igvel 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 

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 



Mary 



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 regard 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. 7. 1829. 

Q 4 



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344 



DELTAS OF THE BALTIC. 



[Book II 



m 



I 



I ii 



r 



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 soundln^^s made 
durmg 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 day 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. 






I 



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, 

L 
L 

* Trans, of Lit. and Hist. Soc. of Quebec, vol. i. p. 5. 1829. 



r 





^ 



Ch. IV.I 



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 Bothma, 
are due to the joint operation of two causes 
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. 



the In- 



Delta of 



We 



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 

w 
f 

* Since writing the third edition, I have visited SweAerx, and 
removed the doubts which I before entertained and expressed re- 
specting the alleged gradual elevation of the land in Scaadinavia., 



See Book ii. chap. xvii. 



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346 



DELTA OF THE RHONE. 



[Book 11 



Mont 



The 



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 Aries into two arms. This 
is the case at present ; one of the branches being now 
called Le Petit Rhone, which is again subdivided be- 



Mediterra 



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 



(par 



Aqn(B 



SexticB, 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, 



I* 




■ i 



M^m. d' Astruc, cited by Von Hoff, vol, i. p. 228- 



I 



*w 



Ch. IV.] 



DELTA OF THE RHONE. 



347 




have names of Celtic origin, evidently given to tliem 
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 

terranean ; 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, 



Med 



Mese 



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 



t 



* 



Lib. II. c. V. 



t Bouche, Chorographie et Hist, de Provence, vol. i. p. 23,, 
cited by Von Hoff, vol. i. p. 290. 

Q 6 



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348 



DELTA OF THE RHONE. 



[Book 11 



By the confluence of the Rhone and the currents of 



Med 



river 



sand-bars are often formed across the mouths of the 

by these means considerable spaces become 
divided off from the sea, and subsequently from the 
nver 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 mclination 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 




r 



< 







i 



ch. iva 



BELTA OF THE RHONE. 



a great abundance of marine shells. By this means? 
yve learn how occasional beds of drifted marine shells 
may become interstratified with fresh-water strata at 
a river's mouth. 



2f 



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 



* 



If 



matter, is perfectly ascertained. In the Muse 
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, 
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. 



! 



* 





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* Hist. Phys. de la Mer. 



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350 



DELTA OF THE PO. 



tBook 11. 



L 

1 



i 



Now, It IS well known, that so great is the quantity 

of water carried ofF by evaporation in some Jakes, 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. 

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 



Wh 



( 



) 



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 Eavenna, 
there is an uninterrupted series of recent accessions 

one hundred miles in length 



of land, more than 



which, withm the last two thousand years, have in- 
creased from two to twenty miles in breadth The 
Isonzo, Tagliamento, Rave, Brenta, Adige, and Vo, 
besides many other inferior rivers, contribute to the 
advance of the coast-line, and to the shallowing of the 





• « 




f» 



ri' 




t 



Ch. IV.] 



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 mam sea. 
Yet even before the practice of embankment was m- 
troduced, the alluvium of the Po advan ced 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; 

but a large part of the Gulf of Trieste and the 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, incrustmg 

shells. He also ascertained, that particular species ot 

testacea were grouped together in certain places, and 

* See Brocchi on the various writers on this subject, 
Foss. Subap., vol. i. p. 118. 



Conch. 



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352 



DELTA OF THE PO. 



[Book 11 



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, 
many other streams, are forming immense beds of 
sand and some conglomerate ; for here 

mountains of Alpine limestone approach within a few 
miles of the sea. 



an 



d 



some 



high 



m the time ot the Itomans, 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 




h 







! 

I 





Ch. TV.] 



DELTA OF THE NILE. 



S53 



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 
hish land would terminate in that abrupt manner 
which generally indicates, in 



a 



Medite 
great depth of water near the shore, except iia 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 attammg 
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 iW/e. — 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 



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354 

of time."* We 



DELTA OF THE NILE. 



[Book II 



been considerably modified since the days of Homer, 
liie ancient geographers mention seven principal 
youths of the Nile, of which the most eastern, the 



Men 



aesian, 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- 
tme 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 
*^- beginning of the fifteenth century, was on this 



Cano- 



embouchure, is now more than a mile inland 
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. f 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 

fand on";."'""''' "''' '^' ^''^^'' ^^--e 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 MareotLs. alcn f^^^.i. r.i ., T ,. , 




ii. p. 107. 



* Geog. Syst. of Herod, vol, 
f Odys., book iv. v. 355. 

t I^ib. I. Parti, pp. 80. 98. Consult Von Hoff, vol. i. p 



244. 



i 



-L 








A - 



Ch. IV.l 



DELTA OF THE NILE. 



355 



r 

connected it with tlie 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 



Mean 



iiiitiu vy tilt- J-"— 7 

der Achelous, and other streams, had formed deltas. 
Esvpt, therefore, he says, like the Red Sea, was 
once a long narrow bay, and both gulft were separ- 
ated by a small neck of land. If the Nile he adds, 
should by any means have an issue mto the Arabian 
Gulf, it might choke it up with earth m twenty thou- 
sand, or even, perhaps, in ten thousand years ; and 
why may not the Nile have filled with rnud a still 
greater gulf in the space of time which has passed 

before our age?"* . j ^ .t,^ 

Mud of the Nile. -The analysis of the mud of the 

Nile -ives nearly one half of argillaceous earth, and 
about" one fourth of carbonate of lime, nearly one 
tenth of carbon, the remainder consistmg of water. 



t 



Mediterranean 



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 o 



* Euterpe, XI. 

t Girard, Mem. sur TEgypte, tomi. pp.348. 3b J 




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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 
fides and currents. 



1 



I 



r^S*. 




j^ 





357 



CHAPTER V. 







.- !* ^ 



>t 



I I 

III i'f ' 



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 vallevs illustrated by the growth of deltas— Grouping 
of new strata in general (p. 371.)- Convergence of deltas 
Conglomerates — Various causes of stratification — Direction 
of laminEe — Remarks on the interchange of land and sea. 

J 

The 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- 




v. i 



fill 




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358 



DELTA OF THE GANGES. 



[Book II 



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. 



( 



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 discharge. 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. 



' 'r 




ti 



1 




n\ 




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- 

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 



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360 



DELTA OF THE GANGES. 



[Book XL 



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 pr^" 
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 theHoogly 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 and shrubs. 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. At length 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 



i 



* 



\ 



. >■ 





I 



t 




Ch. v.] 



DELTA OF THE GANGES. 



361 



P 

V ■ 

beds, which are thrown down rapidly from turbid waters 
durino- 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 b 
carried to a 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 anothe 



stratum of clay.* 

formed 



Major 



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, f The immense 
transportation of earthy matter by the Ganges and 

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. 

f Trans, of the Asiatic Society, vol. vii. p- 14» 



VOL. I. 



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362 



DELTA OF THE GANGES. 



[Book 



cll. 



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 belovr 
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 



Wi 



Whil 



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 floods 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 ; 

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 



Mr 



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II 



Ch. v.] 



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. 

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 



Inundations. 



man 



If human experience and forethought cannot 



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364 



DELTA OF THE MISSISSIPPI. 



[Book 11 



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 tranquiUity 
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 



Mis. 



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, consistino- 

simply of the banks of the river, wearing precisely the 

same appearance as in the inland plains during the 

periodical inundations, when nothing appears above 

water but the higher part of the sloping glacis before 

described.* This tongue of land has advanced many 

Great sub- 
marine deposits are also in progress, stretching far and 



leagues since New Orleans was built. 



* 



Chapter IL 






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♦ 




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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. 



Mississipp 



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. 



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 t 



first, an upper stratum, 



consisting invariably of blueish clay, common to the 



M 



ochreous earth, peculiar to Red River, under which 



M 



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.f 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 m 

* Captain Hall's Travels in North America, vol. iii. P- 338. 
See also above, p. 2f^6. 

I Darby's Louisiana, p. 103. 

E 3 



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566 



PROPORTION OF SEDIMENT 



[Book n 



each. 



Missis 



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. 



iM' 




I 



i\ 



i 



Quantity/ of 



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- 



Mr 



that 



1 

i'5"ooo 



th would have been a nearer approxima- 

I 

tion to the truth.f 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 2^,000 years to turn 
the whole sea into terra firma, assuming it to be 
125,000 square miles in area.j: 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. p. 237- 
f Edin. New Phil. Journ., Jan. 1835. 
. \ Staunton's Embassy to China, Lond, 1797, 4to. vol. ii. p. 408* 



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■^- - 



Ch. v.] 



IN RIVER WATER. 



367 



^, and he 



globe, which reached the sea, to be ,,,. 
imagined that it would require a thousand years tor 
the sediment carried down to raise the general level 
of the sea about one foot. Some writers, on the con- 



Maillet 



watL to contain far less sediment. One of the most 

extraordinary statements is that of Major Rennell, m 

irexcetent'paP-, before referred to, on the delta of 

tiraanges. ''A glass of water," he says, " taken out 
the Changes. j, ^^^^^ ^^^ 

of this river when at its neignt, y ^^ 
in four of mud. No wonder, then he adds, that 
ui luui ui T,„„ij nnirklv form a stratum of 

the subsiding waters should quickly lo 

earth or that the delta should encroach on the sea. 
^"^here must certainly be some — P^^^^^^^^^^^^ 
misprint, in the statement m the Ph 1. T ans. , and 
:i haU conjectured that f learned hydrograph^^^^ 
meant one part in four hundred of mud. In foxmer 
"diUons of this work, I expressed my regret that so 
LTch 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 sohd matter 
transported by certain large rivers to the sea. The 
deficiency of data has now been, in some degree, re- 



movea Dy ine iauuui& ui tilt, x^v..-^.^.- - ^ 

instituted a series of observations " On the earthy 
matter brought down by the Ganges" at Ghazipui, 

above Calcutta.^ , •. 

The first step to be made in all such calculations is u> 



* Phil. Trans. 1781. 



t Journ. of Asiatic Soc, No. 6. p. 238. Jun 
:n Mr Prinsep, Gleanings in Science, vol- ia. p. 



. 238. June, 1832. 

185. 



See 



also Mr. Pnnsep 



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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. 

Everest found that, in 1831, the number of 
cubic feet of water discharged by the Ganges per 
second was, during the 



Mr 



Rains, (4 months) 
Winter, (5 months) 



494,208 
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. 






t« 




i 






Ch. V,3 



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- 

_ • T *Y./i Til ^ b 



pens 



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 ^^i^th 
part • but, as the water is about one half the specific 
eravitv of the dried mud, the solid matter discharged 



iS 



836 



par 



This 



discharge in the 122 days of the rain. The proportion 



of 



paratively insignificant, the total amount during the 
five winter months being only 24.7,881,600 cubic feet, 
and during the three months of hot weather, 38,154,24.0 
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 n;i^tter 
discharged in a year would equal 3,184,038,720 cubic 

feet of granite. 

weio-h 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 



Now about 12i- cubic feet of granite 



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370 



SEDIMENT IN RIVER WATER. 



[Book n 



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 tlie 
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 

ith 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 a 
much solid matter to the sea as the Ganges. 

The most voluminous current of lava which has 



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Ch. v.] 



GROUPING OF STRATA IN DELTAS. 



371 



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. 



yf Strata in Deltas 



The changes which 



arismg 



seas now 



filling 



up 



have taken place in deltas, even smce the times of 
history, may suggest many important consideratmns m 
regard to the manner in which subaqueous sediment 
is distributed. Notwithstanding frequent exceptions, 

from the interference of a variety of causes, 
theTe\re some general laws of arrangement which 
must evidently hold good in almost all the lakes and 

If a lake, for example, be 
endrcled on tw"o 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. ^'''^ 
strata would be divisible into two principal groups : 
the older comprising those deposits which origmated 
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 



The 



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72 



GROUPING OF STRATA 



[Book IL 



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- 
tammg 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 

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 maybe 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 torrent and 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 

At length some of the numerous deltas 



rivers and 



sand 



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J 



Ch. v.] 



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 turh\, 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. 

size of the transported particles 



As the 



average 



one may 



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; 

have been charged, like the Arve where it 
lOins 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, m.arl, or other materials ; 
but after their junction new chemical combinations 
d a distinct colour would be the result, and the par- 

or a greater 



an 



tides having been conveyed ten, twenty, 

number of miles over alluvial plains, would become 



fine 



li 



In deltas where the causes are more complicated, 
and where tides and cm-rents partially interfere, the 
above description would only be applicable, with cer- 



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374- 



CONVERGENCE OF DELTAS. 



[Book II. 



descending from 



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 

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 otlier 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- 



i 



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I 





Ch. v.] 



^ORMATIO^^ 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 
Gano-es 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 
the action of tides and currents, in disseminating 



into 



sediment.* 



of Conglomerates 



Along the base of 



Maritime 



year 



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 

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, 
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. 



A 



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376 



CAUSES OF STRATIFICATION. 



[Book II 



ii.i 




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The horizontal arrangement 



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. 

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 superimposed. A variety of cir- 
cumstances also 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 




I 



I 



,rt 



^J 








Ch. V.3 



CAUSES OF STRATIFICATION. 



377 



Mis 



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 

are converging 



When two deltas 



the intermediate space is often, for 
reLoTs"before°' explained, alternately the receptacle 
of different sediments derived from the convergmg 



streams. 



The one is, 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 
die 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 



com 



either even or slightly undulating, and preserving a 
general parallelism to the planes of stratification. 
Sometimes, however, the laminae 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, m 
company with Professor L. A. Necker, of Geneva, the 
confluence of the Rhpne and Arve, when those rivers 



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* 




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 laminee 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 



Fig. 13. 



Section on the hanks of the Arve at its conflueuQe with the Rhone, shozving 

the stratification of deposits where currents meet. 






1 



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1.1 



1-' -^ 



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Ch. v.] 



CONCLUDING REMARKS ON DELTAS. 



879 



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 is exhibited in older strata of all ages ; and when 
they are treated of, I shall endeavour tnore fully to 
illustrate the origin of such a structure. 



\ 



f 



I may here 



conclude my remarks on deltas, observmg that, im- 
perfect as is our information of the changes wh^ch 



they have undergone within the last three thousand 

years, they are sufficient to shew how constant^ an 

Lerchange of sea and land is taking pl-^ ^ the Jace 

f our lobe. ""^ ^^" Mpfliterranean alone, many 



or our ffiout;- ^^^ ^"^^ -.*^" 

flourishing inland towns, and a still greater number of 
p rts, nol stand where the sea rolled .ts waves smce 
the e^a of the early civilization of Europe. If we could 
compare with equal accuracy the ancient and actual 
state of all the islands and continents, we should pro- 
bably discover that miUions 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 

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 '^ 



inquiry 



* 



* See above, Book i. p. 22 



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380 



CHAPTER VI. 



r 

DESTROYING AND TRANSPORTING EFFECTS OF TIDES AND 



CURRENTS. 



Differences in the rise of the tides- RennelPs Account of the 
LaguJIas and Gulf currents- Velocity of currents- Causes of 

Action of the sea on the British coast (p. 392.) 



currents 



Shetland Islands— Large blocks removed 






Effects of light- 



Isles reduced to clusters of rocks — Orkney Isles 
East coast of Scotland (p. S99.)-East coast of England 
Waste of the cliffs of Holderness, Norfolk, and Suffolk 
Silting up of estuaries (p. 407.) 
Yarmouth estuary 



Origin of submarine forests 
Suffolk coast — 



— Dunwich (p. 411.) 
i^ssex coast _ Estuary of the Thames - Goodwin Sands 
Coast of Kent — Formation of Straits of Dover (p. 420.) 



South coast of 



i 
1 



England 



Sussex 



Hant 



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- 
mg portions of the solid crust of the earth, and remov- 
mg 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 ; 




t 





- I _ ^ J X, ■_ - 



^1 r »T 



Ch. VI.] 



KISE 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 



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- 
ino- tracts where the land is prominent. Thus, at the 



entrance of the estuar 



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 
gulf 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. 
f RoTTime, Vents et Courans, vol. ii. p. 2. 
Quart. Jouru. of Science, March, 1829. 



f Ibid. p. 328. 
Rev. F. Fallows, 



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382 



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-nme 



f 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 Jersey, 
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 Azpres. 

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. * 

t On the authority of Captain Beaufort, R. N. 







I 



'4i 




Ch. VI.] 



CURRENTS. 



383 



Ocean ; 



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. 



to 



West 



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 
that of Brazil, flowing afterwards by the shores 

Indies. The breadth of this 

rur^ent" 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, 
passing the island of Trinidad, it expands, and is 
almost lost in the Caribbean Sea ; but there appears to 



After 



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ii 




384. 



CURRENTS. 



[Book II, 



can gulf, M'hich 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 



) 



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 
surfece 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 



Med 



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 






I 



-\. 



1 -. 




^.1. 



Ch.VI.] 



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. 



^f 



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 



occurs their velocity is much increased. The current 
which runs through the Race of Alderney, between 
the island of that name 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 liour ; 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 



VOL. I. 



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386 



CAUSES OF CURRENTS. 



[Book ir 



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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 

r 

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 
produced. 

Currents Rowing 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 
through the Straits of Gibraltar into 
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 



current settinjj 
the Mediter- 



* Rennell on the Channel-current 



1 









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r"_ _,_x 



tliil I 



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Ch. VI.3 



RELATIVE LEVEL OF DIFFERENT SEAS. 



387 



other where the vapour is condensed and falls m 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 f^O 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. Lepere.* ^ 

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 a half, 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 Ian 1836. 

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388 



CAUSES OF CURRENTS. 



[Book II. 



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 diiference 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 



Med 



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. Inw wafoi- lof a^, — „_ xu- l.i__. 



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 to begin 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 descendmg currents has gone on for a certain time 
m high latitudes, the inferior parts of the sea are made 

* Phil. Trans., 1830, p. 59. 



1 

I 




t' 



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I 



9 * 



m 



i 

I 



Ch. VI.] 



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 



c5ld 



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 a long 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 so long 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, 
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 



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390 



CAUSES OF CURRENTS. 



[Book U. 



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 



1000 miles an hour, or 



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 m which alone this rotation could produce any eiFect, 
and reasons as if- it would in all latitudes cause currents from eas; 
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 raiii is greatly in excess in high instead of lov, 

iafiMinpc. 



t See a table in Capt. Hall's work before cited. 



I 



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3 



J' 

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I 






Ch. VI.] 



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 

- 1 - J.U. — 6)AA Yr»ilt»o 5in V»mir\ from east to 



(of 



west. 



'St 

Tn the case of such a sudden transfer, the eastern 

eoast of America, being carried round in an oppos.te 

rection,might strike against a large body of water wth 
"d us violence, and a considerable part of the con- 
t rnt mightbe submerged. This disturbance does not 
"ccur because the water of the stream, as .t advances 
gaduany into new .ones of the sea which are movmg 
more rapidly, acquires by friction an accelerated ve- 
l" ty. Yef as tWs motion is not imparted mstant- 
anelnsly. the fluid is unable to keep up wth the full 
!peed of the new surface over which rt .s successively 
J ,!ht. Hence, to borrow the language of Herschel, 
whenh; s"eaks ;f the trade winds -'it lags or hangs 
tack" in a direction opposite to the earth s rotation 
Sat is, from east to west," • and thus a eurre„t^wh,ch 

* Id have run simply towards the north but for the 

rotation, may acquire a relative direction towards the 
west, or become a ^outh-easterly current ^ 



Jces are c;n;;rse of the above. The Gulf 

"am flawing from about lat. 20", isatfirst impressed 

witha velocity of rotation of about ^^""'^l^'^^^'^' 

and runs to the lat. W, where the earth revolves only 
!t the rate of 766 miles, or 174 miles slower. I" tn s 

at tne raic u ^ > , result; 

case a relative motion of an opposite kud my 

1 .u« ^i.rrpnt fnav retain an excess , ui j 



and the current may retain 



ZZ '^ eZin;.rto deflect it eastward 

* Treatise on Astronomy, chap. 3 

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392 



ACTION OF THE SEA ON 



[Book II. 



^^ _Thu. it will be seen that currents depend like the 
..des on no temporary or accidental circumstance, 

but on the laws which nr«c,vi-, , ^"i^J»i-dnces, 

heavenly bodies But M.f Tl ""^ "•°"°»' °f *e 

fluence in «1 , *""«'' ""= ^™ °f *eir in- 

fluence in altering the surface of the earth mav he 

po nts ^, ,h^^^ ^^^^^^.^^ ^^^ J 

energy shift pei-petually. The height to which the 
Udes ,„a .,^ ^i^,^^^^ ^^^ ^^ 

depend in a great measure on the actual configuration 
of the land, the contour of a long line of continental or 
uisular coast, the depth and breadth of channels, the 
pecuhar form of the bottom of seas _ in a word, on 
a comhination of circumstances which are made to 
vary continually by many igneous and aqueourcause7 

selves. Although these agents, therefore, of decay 

and reproduction are local in reference to periodsTf 

hort duration, such as those which history embraces 

hey are nevertheless universal, if we exte/d our v eTs' 

to a sufficient lapse of ages. 



/ the Sea on the British 



^' 



If we follow 



tTiP r^oef^ J , -— ""o,., ^o-u^M. — irwetollow 

the eastern and southern shores of the British islands 
rom our Ultima Thule in Shetland to the Landt E„d 
in Cornwall, we shall find evidence of a series of 
changes since the historical era verv UhJl l 
the kind and degree of for.P I [""strative of 

cgree ot torce exerted by tides and 
currents, co-operating with the waves of L sea In 
this survey we shall havo ,,„ . • 

their joint power on i a„ds J'" ."""^ f '"^"8 

es. Jies : L hold, loi^^t ^0°^ r.^Sr 

SheOand Mands.-Th, northernmost group of the 



I" 



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Ch. VI.3 



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 
Ty he mechanical force of the waves. Steep cliffs are 
hollowed out into deep caves and lofty arches ; and 

almost every promontory ends in a f^^'^^f,^^^^; 
imitating the forms of columns, pinnacles andobe^^^^^^^ 



Modern 



tion. 




Drifting of large Masses of 
ations show that the reduction of continuous tracts to 
tuch insular masses is a process in which Nature is 
Z actively engaged. " The Isle of Stenness says 
Dr Hibbert, " presents a scene of unequalled desola- 
uou 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 
n.a.., eight feet two inches by seven feet, and five 
feet one inch thick, was dislodged from its bed, "- 
removed to a distance of from eighty to ninety feet 
„,easured the recent bed from which a block had been 
carried away the preceding winter (a. d. ISI^}, an a 
found it to be seventeen feet and a half by seven feet 
Ind th depth two feet eight inches. The removed 
n^ass had been borne to a distance of thirty feet, when 
Twas hivered into thirteen or more lesser fragments. 



mass. 



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94. 



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 
acchvity to a distance of 1 50 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- 

^^r ^B ^H^^t ^^^^k ^f^^m ^ ^1 H ^1 ^^V ^^^^K ~ 



Fig. 14. 



t 




Stont/ fragments drifted by the sea. Northmavine, Shetland. 



Effects of 



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. 



t 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. 



If 




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Ch. VI.3 



SHETLAND ISLANDS, 



S95 




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 fave 

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-operatmg with the 
violent movements of the ocean in heaping up piles ^f 

1 1 V. Ar^^r Un(\ and beneath the waters, 
shattered rocks on d^yj^"^' ^^^ ^^-^^ ,^,^^ be the 

we cannot but admit f^^J^2e^^^^ ,f ,,eh dis- 
theatre, for myriads of ages, of *e action o 
turbing causes, might present, at some future period 
f upraised far above the bosom of the deep, a scene o 
havoc and ruin that may compare with any now found 
bv the geologist on the surface of our continents, 
^n some of the Shetland Isles, as on the west of 
M ikle Roe, dikes, or veins of soft granite, have 
llered away ; while the matrix in which they were 
"closed, 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 m thicK- 
ness, was first moved from its bed, f o"^ f J/^^;; 
ago, to a distance of thirty feet, and has smce been 
twice turned over." 

* Dr. Hibberl. from MSS. of Rev. George Low, of Fetlar. 

s 6 




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396 



ACTION OF THE SEA ON 



[Book II 



fc 



^^ ^W ^ M^\^ m M.^m m^ w M M W m w w # m Mm #r mT 

" But the most sublime scene is where a mural pile of 
porphyry, escaping the process of disintegration that 
IS devastatmg 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 
agamst 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 



Fig- 15. 




Grind of the Navir 



Passage forced by the sea through rocks of hard 

porphyry. 



X ■ 

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 



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t^ 




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1 



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Ch. VI.3 



THE SHETLAND ISLANDS. 



397 



accumulation of cubical masses, the product of some 

>» jt 



quarry 



It is' evident, from this example, that although the 
greater indestructibility of some rocks may enable 
diem to withstand, for a longer time, the action of the 
elements, yet they cannot permanently resist. There 
are locaUties in Shetland, in which rocks of almost 
every variety of mineral composition are suflPermg dis- 



makes 



clay slate of Fitfel Head, on the serpentme of he 
Vord Hill in Fetlar, and on the mica-schist ot the 
Bay of Triesta, on the east coast of the same island, 
which decomposes into angular blocks. The quartz 



Walls 



schist of Garthness, suffer the same fate. 



Destrtcction 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 theDrongs, between Papa Stourand 

Hillswick Ness. 




^ 



* Hibbert, p. 528 



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398 



ENCROACHMENTS OF THE SEA ON 



[Book IX 



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 



- ^ 



If: , f . 



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I 



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Fig. 1 7 




Granitic rocks to the south of Hillswick Ness, Shetland. 

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 



1 



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i; :vii 





1 



Ch- VI-l 



THE EAST COAST OF SCOTLAND. 



399 



Midway 



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 hght-- 
house was erected in 1807, since which time the new 

strait has grown broader. 

Eastcoast of Scotland. -T o pass over to the mam 
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 Kmcardineshire, 
an illustration was afforded, at the close of the last cen- 
turv of the effect of promontories m protectmg a line 



of low-shore. 



Math 
^f 7ohnIa7en, was buill on an ancient shingle beach^ 



protected by a projecting ledge of limestone rock 
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. 



Montro 



Esk and the South Esk rivers pouring annually into 
the sea large quantities of sand and pebbles, yet they 
Lave 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 



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Niii 



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 hghthouses 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. 



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 or 
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, t 



/ 



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 
f Ed. Phil. Journ. vol. iii. p. 54. 1820. 



>. 



»• 




\ 





Ch. VI.3 



THE EAST COAST OF SCOTLAND. 



401 



'i» 



hich 



Forth may be mentioned the submarine forests w 

have been traced for several miles by Dr. Hemmg, 

1 ^ *h^ mariiins of those estuaries on the north and 

1Z Xrerof the county of Fife.- Tb. a«uvia. 
tracts, however, on which such forests grow, general y 
occuBV spaces which may be said to be m dispute 
ZJL .he river and the^ ^^^^^^l f^^Tf^ 



lost and won. 



Estuaries 



) 




S:ra r ncy to heUe silted up in parts ; but the 

le tracts, ^ !^^:-r:!Z;T^ 
iTw^rioT^a^abited, ^ust generally be 

Ired'by artificid -"^Tv ' h t S a! h 
sea devours, as it advances, the high as well as the 
„: pa ts o( the coast, breaking down, one after 
an" ther, the rocky bulwarks which protect the mouths 
of estuaries. The changes of territory therefore, 
:i.h" L genend line of coast are all o a subonh- 
S nature: in no way tending to arrest the march of 
rttgreat ocean, nor to avert the destmy eventua^ y 
awaiting tl,e whole region ; they are hke he petty 
wars and conquests of the independent stages and 
republics of Greece, whUe the power of Macedon 
wal steadily pressing on, and preparing to swallow up 

the whole. . » «f 

On the coast of Fife, at St. Andrew s, a tract ot 

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 Grail, ^nthe 
lie county, in 1803. On both sides of the Fr|^ ^ 
Forth, land has been consumed ; at North Berwick m 



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402 



ENCROACHMENTS OF THE SEA ON 



[Book 11 



particular, and at Newhaven, where an arsenal and 
dock, built in the reign of James IV., in the fifteenth 
century, has been overflowed. 



Bast coast of England. 



English coast, 



If we now proceed to the 



we find records of numerous lands 



having been destroyed in Northumberland, as those 
near Bamborough and Holy Island, and at Tynemouth 
Castle, whichnow 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. 



/ 



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 14<6 feet above high water, the 



r 



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> 111 



n\^ ¥ 



1 



Ch. VI.l 



THE EAST COAST OF ENGLAND. 



403 



Whole being composed of clay, with pebbles scattered 

1 .'i. * 



through it 



iT^the old maps of Yorkshire, we find spots, 
. hanks in the sea, marked as the ancient sites ot 

and villages of Auburn, Hartburn, and 



the towns 



« ,i. " Of Hyde," says Pennant, " only the tradi- 

■' Ipft ■ and near the village of Hornsea, a street 

"2d Hotsea Beck has long since been s.aIlowed."+ 
called Hornsea ^^^ .^ p^^^ 

Owthorne and •' ^^^ * " ^^^^ . b„t these places 

r zrve'r IS *d. - :r ~f : 

~ r — i^fr at" ::£tai/ed th. 

year.X ^ot unrea ^^ ^^^^^^ ^^^ 

", T.^ZZ a'Cering Into the estuary 
11 Humber liU cause great devastation. § Pen- 
.after speatog of the silting up of some ancient 
nant, »"" ^f^ J „b,erves, " But, in return, the 
"" Ls mad m St ample reprisals ; the site, and even 
Z vey names of sev'eral places, "-e towns of nc^e 

.liHnmber are now only recorded ra history , 
upon the Humber, are 3 ^^^^^^ 

onri Ravensper was at one time a i^voi \ ^ 

7tZ2l m.), and a port so very considerable m 
W32 that' Edward Baliol and the confederated En- 
f h Baronrsailed from hence to invade Scotland ; and 
Henry I v., in 1 399, made choice of this port to land 
f, to effect the deposal of Richard II. ; yet the whole 
of his has long since been devoured by the merciless 



* Phillips's Geology of Yorkshire, p. 61. 

+ Arctic Zoology, vol. i. p. 10. Introduction 

1 For this information I am indebted to Mr. 



Phillips, of 



York. 



§ Phillip's Geology of Yorkshire, p. 60. 



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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 
«5 the German Sea, which devours whole acres at a 
time, and exposes on the shores considerable quantities 
ot beautiful amber. " f 

According to Bergmann, a strip of land, with several 
villages, was carried away near the mouth of the 
Humber in 1 475. 

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 draiqed 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 
ot the sea, whereby several parishes have been at dif- 
ferent times overwhelmed. 

f'ff''~'^^ ^'^"^^ "^^t to the cliffs of Norfolk 
and Suffolk, where the decay is in general incessant 
and rapid At Hunstanton, on the north, the under- 
mimng of the lower arenaceous beds at the foot of the 
chff 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 



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--.iWtar 



U 



Ch. VI.] 



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 
CArundo 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 

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 



year 







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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 

E 

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 
pouth 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. 32. 



t Ibid. 






1^ 



^^ 



I L 



[ ' 






Ch. VI.] 



SILTING UP OF ESTUARIES 



407 



Winterton 




01 blown sttuu? i/w^.Tv.^ — 1 J J 

barred up and excluded the tide for many hundred 
vears from the mouths of several small estuaries ; but 

records of nine breaches from 20 to 120 



wise, 



yards wide, having been made through these, by which 
immense damage was done to the low grounds m the 
tprior A few miles south of Happisburgh, also, are 
hi Is of blown sand, which extend to Yarmouth ; and 
tZe are supposed to protect the coast, but m fact 
:^:: formation proves that a temporary res^te of h 
incursions of the sea on this part is Per-t^ed ^^^^^^^^^ 
present set of the tides and currents. Were it other 
^ the land, as we have seen, would give way. 

"^^^ll^t^^— At Yarmouth, the sea has 
not I^vTncTd 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 ciyl represented, even in the thirteenth and 
Founeenth centuries, as " situated on the banks of an 
arm o? 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 obstructmg 
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 

b 



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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.f 

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 YarCj 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 Aide entered the sea at Aldborough, until its 



* 



Taylor's Geology of East Norfolk, p. 10. 



t For remarks on the origin of Submarine Forests, see Book 
III. chap. 16. 




' t 



- J- 




iM'iii ■■ 





ji 



ch. Via 



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- 



.11, IIU i^"" ^^.. ^^ « — 

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 maybe asked why the rivers on our east coast 

are always deflected southwards, although the tidal 
current flows 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 

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. 



German ocean. 



VOL. I. 



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410 



r* 



ENCROACHMENTS OF THE SEA 



[Book II. 



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 
w eed from the bed of the sea, and casts it ashore. 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 

r 

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^ a. The dotted lines express a series of ridges of sand and 
shin""le, forming the extremity of the triangular space called the 

Ness. 
h h h. The dark line represents the inland cliflF on which the 

town of LowestoiF stands, between which and the sea is the 

Ness. 



* From Mr. R. C. Taylor's Mem., see below. 




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1 






Ch. VI.] 



ON THE SUFFOLK COAST. 



411 



put 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 

r 

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 

is forming externally, which by the like process 
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." 



Meanwh 




Destrmtion of Dunwich by 



The sea under- 



mines the high cliffs near Gorton, 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. R. C. 
Taylor, Phil. Mag. Oct. 1S27. p. 297. 

T 2 



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412 



ENCROACHMENTS OF THE SEA ON 



[Book II. 



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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 ^nd skeletons exposed to view — some lying 
on the beach, and rocked 



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Oil. VLl 



THE EAST COAST OF ENGLAND. 

^' In cradle of the rude imperious surge 



413 



W-' ')\: 



5> 



site 
sea. 



>) 



* 



Of these cemeteries no remains can now be seen. 
T?.v also says, " that ancient writings make mention 
7. wl a'mlle and a half-to the east of Dunwich, the 

of which must at present be so far withm the 

This city, once so flom-ishing and populous, is 

now a small village, with about twenty houses, and one 

^"^ t"Uion, '^ that the tail^s sat in 
Jir lops at Dunwich, and saw the ships m .armou h 
Bav" but when we consider how far the coast at 

Lo'w'estoff Kess projects between tbese^^^lels 
cannot give credit to the tale, which, nevertheless 
; ves how much the inroads of the sea in times of c. 
had prompted men of lively imagination to indulge 
their taste for the marvellous. ; 

Gardner's description of the cemetenes la.d open 

waves remlod us of the scene which has been 



by the 



ikf 



oTthe verge of a cliff, which the sea has undermined 

are represented the unshaken tower and western end 
arerepic ^^ ^^ ^.^^^ .^ ^^^^^ and the 

The waves 
and invaded the 



of an abbey. The eastern aisle is gone 
pillars of the cloister are soon to follow. 



have almost isolated the promontory. ^ 

ee^etery, where they have n,ade sport w.tjhe ™or.a 



relics, and thrown up a skull upon the beach, 
foreground is seen a broken tombstone, erected, as is 
legend tells, " to perpetuate the memory of one whose 
.ie is obliterated, as is that of the county for wh^d. 

. Gustos Rotulorum.' " A cormorant is percnea 
monument, defiling it, as if to remmd some 



name is 
he was 
on the 



* Consequences of the Deluge, Phys. Theol. Discou-s. 
+ History of British Birds, vol. ii. P- 220. Ed. 1821. 

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414 



ENCROACHMENTS OF THE SEA ON 



[Book n 



some 



It. 



r 

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 

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 onlj 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 
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, 
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. 



Be- 



1*1^ 






» 



I 







VI 



m '~\ 






V 

1 




Ch. VI.] 



THE EAST COAST OF ENGLAND. 



415 



It appears that, within the memory of Pe-ons now 
livirL the Orwell river continued its course m a moie 
d rect line to the sea, and entered to the north mstead 
of the south of the low bank on which the fort last 

mentioned is built. • , 

V,..:c.-Harwich, in Essex, stands on an isthmus 



which will probably become an island in little more 
rhan ha f - -ntury ; for the sea will then have made 

! breach near Lower Dover Court, should it continue 
a breach near ^ ^^^^ ^^^.^^ ^^^ j^^^ 

to advance a. rapidly as ^ ^^ ^^^^ ^ .,„«;dprable 

fifty years 



Within 



fitty years, v, "■—-•• g^^j^h, built twenty- 
.pace between ^^^^^ . „f ,h, fortification 

r S ~ept\:;: La the .. ovetha„,s 
*: :i:e/ Smee the year 1 807, a field c*d the 
Vicar's Field, which belonged to the living of Harwich, 
has been totally annihilated.* ^ , . 

At Walton toe, in the same county, tie dilt», 
comno^d of London day, capped by the she ly sands 
of the crag, reach the height of about 100 feet, and 
fJLJly undermined by the wave, T^e 



Waltoi 



cliffs to the south are constantly disappearmg. 

iZ-m of Sfe«.-On the coast bounding the 

estt^ of the Thames, there are numerous examples 

hot f the gain andloss of land. The Isle of Sheppey, 

which is not about six miles long by four in bread h, 
Ts composed of London clay. The cliffs on the north 
lich are from sixty to eighty feet high, decay rapidly, 

fifty acres having been lost within the last t"».y ^J^ 
The church at Minster, now near the coast, is said to 
tet ten in the middle of the island fifty years ago f , 

. On .Ulbority of Dr. Mitchell F G. S ^^^ 

i For this inrotmation I am indebted to W . uu 



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ii 






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 Heme 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. Keculver (Regul 



military station in the time of the Romans, and appears, 
from Leland's account, to have been, so late as Henry 
Vni.'s reign, nearly one mile distant from the sea. 



Fig. 1 9. 




View of Reculver Church, taken in the year 1781. 



d.B »»>»»■■' 



.■.•■' 



1. Isle of Sheppy 

2. Ancient chapel now destroyed. The cottage between 
chapel and the clifF was demolished by the sea, in 1782. 



this 



^ On the authority of W. Richardson, Esq., F. G. S. 



It 






1 



I 



S 





I I 




I 



t 



I 



Ch. VI.] 



THE EAST COAST OF ENGLAND. 



417 



Ma 



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 
,.... ._ ....... They were eighty yards nearer the 

sea than the church, and they are spoken of m the 
" Topographica Britannica" in the year 1780, as hav- 
ing recently fallen down. In 1804, part of the 



into one mass. 



Fig. 20. 




Reculver Churchy in 1834. 

* Vol. ii. New Series, 1809, p. 801 

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418 



GOODWIN SANDS. 



[Book ir 



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 ThaneL — 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 centurj^, 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 Baj, 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. 




* 



it 




*^ 



* 



■- y" 






\\ ii 




I 



I 



419 



Ch.VI.: FORMATION OF THE STRAITS OF DOVER. 

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 

contemplation by the Trinity 



this shoal was in 



on this snoai wao ^^ -^ r- - ^ 

Board in the year 1817, it was found, by borings, that 



sand 



blue clay. An obscure tradition has come down to us, 
that the estates of Earl Goodwin, the father of Harold 
who died in the year 1053, were situated here, and 
some have conjectured that they were overwhelmed 
by the flood mentioned in the Saxon chromcle, sub 
anno 1099. The last remains of an island, consisting 
like Sheppey, of clay, may perhaps, have been earned 

away about that time. 

There are other records of waste in the county oi 
Kent, as at Deal ; and at Dover, where Shakspeare s 



Fig. 21. 





F \ 









■ 1/ .A^ f^ 1 



Sr^ if '■ J~ 




"shakspeare' s Cliff in 1836, seen from the North-east 

* Geog. of Herod, vol. u. p. 326. 

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II 



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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, f 

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 
never have been introduced by man. He also attri- 
buted the rupture of the isthmus to the preponderating 



Dodsley's Ann. Regist. 1772, 

t Stevenson on the Bed of the German Ocean, 
Journ., No. v. p. 45. 



Ed. Phil. 




■ 




t 



1 
J 



I 




r F - - -J 





Ch. Via 



ENCROACHMENTS OJ? 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- 



Mississipp 



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," 

\ 

In framing these speculations, however, we must not 
overlook the great effects which particular combin- 
ations of qauses might produce without violence. The 
chalk supposed in this instance to have been removed, 

of itself a marine deposit, and must at some 



was 



* Cuvier, Eloge de Desmarest. 



1 \'- 



41 



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422 



ENCROACHMENTS OF THE SEA ON 



[Book U 



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 

r I 

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 pur coasts acquired a considerable part of 
their actual height and contour.f 

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 



* See Book ii. chap. 17- 
f Phil. Trans., 1716. 



r Marsh, or Dungene; 

f See Book iv. chap. 22. 



« 



K 



i 



11 






il 



Ch. VI.] 



THE SOUTH COAST OF ENGLAND. 



423 



(I 



sea, 



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 earhest 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 
Eno-lish 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 other'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 

but it is now two miles distant from it. The 
„..„hbouring 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 buih en- 
tirely of oak, and much blackened, f 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.:}: 

/Swssea;. — 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. ^G. 
i Webster, Geol. Trans., vol. ii. p. 192. 



4 
'4 



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424 



ENCROACHMENTS OF THE SEA ON 



[Book 1 1. 



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 



r 



J 



* Mantell, Geology of Sussex, p. 293. 



I 



- 4 



* 







* 



!, '( 



¥m 



.t 



Ch. VI.] 



THE SOUTH COAST OF ENGLAND. 



425 



w 



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. 



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. 



Hampshir 



f 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 outhne 
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. , t i f 

The same phenomena are repeated m the Isle ot 

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 

_ L 

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 



i 

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1 



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 Hordwellj, 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. 



of Nov 



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- 
siite 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 the 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, ivhich^ by degrees, become en- 









ti 



%• 




■ I 



r 



I 



r 



I 






Ch. VI.] 



THE SOUTH COAST OF ENGLAND. 



42 



I 



larged into 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 

M 

of limestone. . . 

In 1665 the cliffs adjoining the principal quarries m 
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 clitts, 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, 
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- 



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428 



CHESIL BANK. 



[Book II 



J 

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. 
Ihe 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. 



*4 

i4 



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429 



Ch. Via DORSETSHIRE - DEVONSHIRE - CORNWALL. 

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- 

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 

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, 



water, 



Worcester 



« 



Martin 



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." 

Devonshire — Cornwall. — At Lyme 



Dorsetshire 



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 ISOO-f 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 
;« tv.c. rmirse of the last two or three centuries.! It 



* De la Beche, Geol. Man. p. 82. 

t This ground was measured by Dr. Carpenter of Lyme, m 
1800, and again in 1829, as I am informed by Miss Mary Annmg 
of Lyme, well known by her discoveries in fossil remams. 

J Boase, Trans. Royal Geol. Soc. of Cornwall, vol. u. p. 129. 



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430 



WEST COAST 



ENGLAND, 



[Book II. 



\ 



Michael's Mo 



rock, was formerly situated in a wood, several miles 



) 



(C 



Wood 



Mount 



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.f 

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 

r 

* Boase, Trans. Hoyal Geol. Soc. of Cornwall, vol. ii. p. 135. 
f Ibid. p. 130. 



» 





«^*--^- 



431 



Ch. VI.] LOSS OF LAND ON THE COAST OF FRANCE. 

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 
vear 1764, the coast of Cheshire between the rivers 



some affirm more than half a mile, by the advance of 
the sea upon the abrupt cliffs of red clay and marls. 



Within 



have been successively abandoned.* There are tra- 
ditions in Pembrokeshire t and Cardiganshire $ of far 
glter losses of territory than that which the Lion- 
Lsse tale of Cornwall pretends to c--e--ate 
Thev are all important, as demonstrating that the 
earliest inhabitants were familiar with the phenomenon 
of incursions of the sea. 



yf land on the coast of 



The French 



coast, particularly that of Brittany, where the tides 
rise to an extraordinary height, is the constant prey of 

In the ninth century many villages and 



lITe r: o:;:a .« have bee. ea.ied awa, *e 
eoa. u„aer,oi„g great cMnge. wH-eb^^'X^ "Z. 



^thlf Zrgneuf, and several othersi^t^^^^^^^^^^ 
Lnrhood were overflowed m the year ISOO. In 1735, 
d„ tag a great storm, the ruins of Palnel we seen 

uuiiug «, 5 traflition. more- 



uncovered in the sea. 



A romantic tradition, more- 



rrrardeseraelf;;™ the fabulous ages of the de- 
duction of the south-western part of Brittany, whence 
we my probably infer some great inroad of the sea at 
a remote period. H 

T^^eson's Ed. new Phil. Journ. No. 8. p. 386. 
* Stevenson, Jameson b « nn the Deluge," 

I Camden, who cites Gyraldus, also Ray, "On the ii ., 



Phys. Theol. p. 228 
1 Meyrick's Cardigan. 
§ Von HofF, Geschichte, &c. vol. i. p. 49. 



II Ibid. p. 48. 



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433 



I 



GLOSSARY 



OF GEOLOGICAL AND OTHER SCIENTIFIC TERMS USED 



IN THIS WORK. 



t! 




i 



ACKPHAI.O.S. 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. Eti/m., a, a, without, and >t£<t.*X., cephale, the head. 
Adipocike. 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 . 
Albite. See " Felspar." 
A TKic An apparatus for distilling. 

T^ 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._ 
Ai-i-tiviAL. The adjective of alluvium, which see. 
At..uvioK. Synonymous with alluvium, which see. 
AtLTiviuM. 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 farther explanation of the term 



as 



used in this work, 



Vol, III. p. 196., and Vol. IV. 



Alum is the base of pure 



p. 44. 

Alum-stone, Alumen, Aluminous. 

cZ and strata of clay are often met with contammg much 
iron-pyrites. When the latter substance decomposes, sul. 
phuric acid is produced, which unites with the aluminous earth 



VOL. I 



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GLOSSARY. 



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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, 
Ammonite. 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. 

Amorphous. Bodies devoid of regular form. Etym., a, a, with- 
out, and fxop<pyj, morphe, form. 

Amygdaloid. One of the forms of the trap-rocks, in which 
agates and simple minerals appear to be scattered like almonds 
in a cake- Ett/m,, aixvy^aXa,, amygdala, an almond. 
^Analcime. 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. 
ANOrLOTHERE, Anoplotherium, 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,, avoTrXog^ anoplos, unarmed, and ^jjp:ov, iJierion, a 

wild beast. 
Antagonist Powers. Two powers in nature, the action of 

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. 

Antekn^* 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,, avSpa,^, anthrax ^ coal. 

AnthracotheriuM- 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.y 
avQ^a^, anthrax, coal, and 9-Jipiov, therioUy vrild beast. 



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GLOSSARY. 



435 



Anthbopomouphous. Having a form resembling the human, 
Eti/m., avSpaiffo?, anthropos, a man, and (xoi-^-n, 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- 
' ^^ards 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 b, b 
the synclinal lines. Etym., arn, anti, against, and ;cX(v<», clmo. 



to incline. 



Fig. 22. 




Antiseptic. Substances which prevent corruption in animal and 
vegetable matter, as common salt does, are said to be anti- 
septic. Etym., aim, against, and ctutt*, sepo, to putrefy. 

Arenaceous. Sandy. Etym. , arena, s^nA. 

Akgili-aceous. Clayey, composed of clay. Etym., argilla, 

clay. 
Abbagonite. a simple mineral, a variety of carbonate of lime, 

so called from having been first found in Arragon, in Spain. 

AuGiTE. A simple mineral of a dark green, or black colour, 



forms 



/" 



-\ 



rocks. Name applied by Pliny to a particular mineral, 

* 

from the Greek avyn, auge, lustre. 
Avalanches. 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. 

Basalt. 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 

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436 



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 Ethiopian word 
signifying iron. The rock often contains much iron. 
« Basin " of Paris, « Basin " 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. 

Belemnite, An extinct genus of the order of molluscous 
animals called Cephalopoda, having a long, straigM, and 
chambered conical shell. Etym,^ SeXsfxvov belemnouy 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 Shale. An argillaceous shale, much impregnated 
with bitumen, which is very common in the coal measures. 

BiENDE. 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. 

r 

Bluffs. High banks presenting a precipitous front to the sea 
or a river. A term used in the United States of North 
America. 

BoTRYoiDAL. Resembling a bunch of grapes. Etym^y Bor^vq^ 
hotrysy a bunch of grapes, and Bihq, eidos, form. 

Boulders. 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. 

r 

r 

Calc Sinter. A German name for the deposits from springs 
holding carbonate of lime in solution — petrifying springs. 
Etym., kaVcy lime, sintern, to drop. 



i 






J 



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Y 



< 



GLOSSARY. 



437 



Calcaibe Gbossier. An extensive stratum, or rather 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 grassier, coarse. 
Calcakeous Rock. Limestone. Etym., calx, lime. 
Calcareous Spak. Crystallized carbonate of lime. 
Calcedony. a siliceous simple mineral, uncrystallized. Agates 

are partly composed of calcedony. . 
Carbon. An undecomposed inflammable substance, one of the 
simple elementary bodies. Charcoal is almost entirely com- 
posed of it. Etym., carho, coa\. 
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. ^ • . 
Carbonated Springs. Springs of water, containing carbonic 
acid gas. They are very common, especially m volcanic 
countries ; and sometimes contain so much gas, that if a 
little sugar be thrown into the water it etfervesces like soda- 



water. 



Carbonic Acib Gas. A natural gas which often issues from 
the ground, especially in volcanic countries. Etym., carlo, 
coal ; because the gas is obtained by the slow burning of 
charcoal. , . i 

Carboniferous. A term usually applied, in a technical sense, to 
an ancient group of secondary strata (see Table L M, Vol. IV. 
p. 305.) ; but any bed containing coal may be said to -be car- 



boniferous. 



fi 



Cataclysm. A deluge. Et7/m., jtctrccKKv^oj, catacluzo, to deluge. 
Cephalopoda. A class of molluscous animals, having their organs 

of motion arranged round their head. Etym., x£4>^^^. 

cephale, head, and ^ro^a, poda, feet. 
Cetacea. An order of vertebrated mammiferous animals mha- 

biting the sea. The whale, dolphin, and narwal are examples. 

Etym.y cete, whale. 
Chalk. A white earthy limestone, the uppermost of the second- 
ary series of strata. See Table I. F, Vol. IV., p. S02, 

A siliceous mineral, nearly alUed to calcedony and flint, 



Chert. 



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438 



GLOSSARY. 



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but less homogeneous and simple in texture. A gradual pas- 
sage from chert to limestone is not uncommon. 

Chloritic Sand. Sand coloured green by an admixture of the 
simple mineral chlorite. Utym,, x^^pog, cMoros, green. 

Cleavage. Certain rocks, usually called slate-rocks, may be 
cleaved into an indefinite number of thin laminae 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 divi^de columnar basalt into prisms are joints. The 
masses of rock included between joints cannot be cleaved 
into an indefinite number of laminae or slates, having their 
planes of cleavage parallel to the joints. See first part of 
Chap, xxvii. Book iv. 

Clinkstone, called also phonolite, a felspathic rock of the trap 
family, usually fissile. It is sonorous when struck with a 
hammer, whence its name. 

Coal Formation. This term is generally understood to mean 
the same a& the Coal Measures. See Table L, 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. 

CoLEOPXERA. An order of insects (Beetles) which have four 

wings, the upper pair beiug crustaceous and forming a 

shield. Ety'Ti.^ stcAe^?, coleos, a sheath, and Trrspovj pterortj 
a wing. 

Conformable. 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, 
Fige 139., Vol. IV. p. 120., rest conformably on the in- 
ferior set c, d; but c, d rest unconformably on E. 

Congeners, Species which belong to the same genus. 

Conglomerate or Puddingstone. 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. Etym.^ con^ together, glomeroy to heap. 

Cokifer^. An order of plants which, like the fir and pine, bear 



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GLOSSARY. 



439 



Coomb. 



cones or tops in which the seeds are contained. EHjm., 

conus, cone, and fero, to bear. ^ , i f„. « 

viB A provincial name in different parts of England tor a 
valley on the declivity of a hill, and which is generally with- 

A rubblv 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. _ 
Cokksxok: a provincial name for a red limestone, forming a 



out water. 

CORNBRASH 



subordinate bed in the Old Red Sandstone group. _ 
CosMOGO^'^, Cosmology. Words synonymous inmeanin 



g, ap- 



C B AG. 



lOGOKV:, \^\Joxyi.yjxj^ ■ . . • _ J„ „f 

plied to speculations respecting the first ongm or mode of 
creation of the earth. Etym., ko^/.os, kosmos, the world, and 
Tov^, gonee, generation, or Myos, logos, discourse. . 

J ^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. 



Crater. 



.... The c'ircular cavity at the summit of a volcano, from 
which the volcanic matter is ejected. Etym., crater, a great 



cup or 



bowi. 



Ckb.ac.ous. Belonging to chalk, ^^y-'--' ff^' 



, ^„, A miner's or mineral surveyor's term, to express the 
rising up or exposure at the surface of a Stratum or series of 



Crop Out. 



strata. 



^ i?A-RTTT See *^ Earth's crust." 

PRTTST OF THE JjjARTH. occ ^ 

CkLxacea. Animals having a shelly coating or crust which 
tley cast periodically. Crabs, shrimps, and lobsters, are 

examples. ^^^ ^^ ^^^^^^ 

CrvYPTOGAMic. A name applied to a class oi p d , 

mosses, sea-weeds, and fungi, in which the fructification 
or organs of reproduction are concealed. Eti^m. , Kpv^ros, 
kryptos, concealed, and yafios, gmnos, marriage. _ 

Simple minerals are frequently found m regular 



Crystals. 



forms, with facets like the drops of cut glass of chandehers^ 
Quartz being often met with in rocks in s«cn forms, and 
beautifully transparent like ice, was called ro^ccrystal, 
Deauuiui ^ r /- V for ice. Hence the 

. KOvaraWos, crystallos, being Greek tor ice. 

regular forms of other minerals are called crystals, whether 



t 



;hey be clear or opake. 



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440 



GLOSSARY. 



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Crystallized. A mineral which is found in regular forms or 
crystals is said to be crystallized. 

Crtstalune. 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 crystallhie 
texture. Sugar-candy and calcareous spar are crystallized. 

Cycade^. 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 KVKas, cycas^ 
a name applied by the ancient Greek naturalist Theophrastus 
to a palm. 

r 

CYPEiiACEiE. 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 gramine^B they constitute what writers on bota- 

, nical geography often call glumacecB. 

r 

Debacle. 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,y dShacler^ 

French, to unbar, to break up as a river does at the cessation 

of a long-continued frost. 

Delta. 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. 

Denudation. The carrying away by the action of running water 
of a portion of the soHd 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. 

Deoxidized, Deoxidated. Deprived of oxygen. Disunited 
from oxygen. 

Diagonal Stratification. For an explanation of this term, see 
Vol. IV. p. 79. 



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GLOSSARY. 



441 



veins. 



Dicotyledonous. A grand division of the vegetable kingdom, 
founded on the plant having two cotyledons or seed-lobes. 
Etym., ^is, dis, double, and kotvXtj^oi^, cotyledon. 

Dikes. 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 
both sides of them having wasted away, they are called m the 
north of England and in Scotland dikes, the provincial name 
for wall. It is not easy to draw the line between dikes and 

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. 

Diluvium. 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. 

Dip. 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. ^ , - , , i 

An order of insects, comprising those which have only 

Eti/m., Sts, dis, double, and Trrepoy, pteron, 



DiPTERA. 



two wings 



wing 



DOLERITE. 



One of the varieties of the trap-rocks, composed of 

augite and felspar. 
Dolomite. A crystalline limestone, containing magnesia as a 
constituent part. Named after the French geologist Dolo- 



mieu 



Dunes. Low hills of blown sand that skirt the shores of Hol- 
land England, Spain, and other countries. 

Earth's Crust, Such superficial parts of our planet as are ac- 
cessible to human observation. 

Elytra. 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., eXvrpov, elytron, a sheath. 

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GLOSSARY. 



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Eocene. See explanation of this word, Vol. III. p. 370. 

Escarpment. The abrupt face of a ridge of high land. Etym^^y 
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.y cestus, the tide. 

ExpERiMENTUM Crucis, A dccisivc 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. 

Exuvi^. 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. Etyia,^ exiiere, to put off or divest. 

Faluns, 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. 

Fault, 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, 



clay, &c. 



Fig. 23, 



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The strata a, &. 

c, &c., must at 
one time have 
been continu- 

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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 



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GLOSSARY. 



443 



its Floba. The term is derived from the Fauni, or rural 

deities, in Roman Mythology. 
Felspar. A simple mineral, which, next to quartz, constitutes 
the chief material of rocks. The white angular portions m 
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. - 
Felspathic. Of or belonging to felspar. 

Ferruginous. Any thing containing iron. Et^m., ferrum, iron. 
Floetz Rocks. A German terra applied to the secondary strata 
by the geologists of that country, because these rocks were 
supposed to occur most frequently in flat horizontal beds. 
^ft/m.,/ofz, a layer or stratum. 
Flora. The various kinds of trees and plants found in any 
country constitute the flora of that country in the language 

of botanists. 

Fluviattle. Belonging to a river. Etym., fuvius, a river. 

Forami^ifera. A name given by D'Orbigny to a family of 
microscopic shells, several of which are figured m Plate IS. 
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. 
Fossil. All minerals were once called fossils, but geologists 

riow use the word only to express the remains of animals and 

plants found buried in the earth. Ety7n., fossilis, any thing 

that may be dug out of the earth. 
FossiLiFEROUS. Containing orga,nic remains. 

Galena. A metallic ore, a compound of lead and sulphur. 

has often the appearance of highly polished lead. FJpn.y 

yaKeci, galea, to shine. ^ 

Garnet. A simple mineral, generally of a deep red colour, 

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GLOSSARY. 



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crystallized; most commonly met with in mica slate, but 

also in granite and other igneous rocks. 
Gastjeropods. a division of the Testacea in which, as in the 

limpet, the foot is attached to the body. JEti/m., yaorTTjpf 

gaster, belly, and 7ro5a, 2^oda, feet. 
Gault. 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. F» 

Vol. IV. p. 302. 
Gem, or Gemmule, from the Latin gemma, a bud. The term, 

applied to zoophytes, means a young animal not confined 

within an envelope or egg^ 
Geology, Geognosy. Both mean the same thing, but with an 

r 

unnecessary degree of refinement in terms, it has been pro- 
posed to call our description of the structure of the earth 
geognosy [Etym.y yea, gea, earth, and yivcoaKiti ginosco, to 
know), and our theoretical speculations as to its formation 
geologt/ [Etym.y yea, and Xoyos, logos, a discourse). 

Glacier. Vast accumulations of ice and hardened snow in the 
Alps and other lofty mountains. Etym,, glace, French for 
ice. 

Glacis. 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. 

Gramine^. 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 sotnetimes 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. 

Greensand. Beds of sand, sandstone, limestone, belonging to 



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GLOSSARY, 



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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, 

&c. See Vol. IV. p. 271. , , ^ ,, , ^ 

A variety of trap, composed ot hornblende ana 



Greenstone 
felspar. 
Grevwacke 



GrauwacJce, a German 



Gypsum. 



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 nanie 
grau, being German for grey, and wacke being a provmcial 

miner's term. 
Grit A provincial name for a coarse-grained sandstone. 

u» A mineral composed of lime and sulphuric acid, hence 
call'ed 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 m 
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. 
Gypseous, of or belonging to gypsum. _ _ 

Gtrogonites. 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., yvpos, gyros, curved, and 70m, 
gonos, seed, on account of their external structure. 

Hemipxeka. An order of insects, so called from a peculiarity in 
their wings, the superior being coriaceous at the base, and 
membranous at the apex, hh-^<Jv, liemisu, half, and irrepov, 

pteron, wing. 
Hornblende. A simple mineral of a dark green or black colour, 
which enters largely into the composition of several varieties 

h ■ 

of the trap rocks. _ 

HoRNSTONE. 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. 



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446 



GLOSSARY. 



Hydrophytks. Plants which grow in water. Eti/77i,, iSwp, 
hydor, water, and (pvropy phyton, plant. 

Hypogene Rocks. For an explanation of this term, see Vol. IV. 
p. 379. 

Incandescent. White hot-having a more intense degree of 
heat than red heat. 

IcEBEKG. 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. 

Ichthyosaurus. A gigantic fossil marine reptile, intermediate 
between a crocodile and a fish. Etym., ixSvs, ichthus, a fish, 
and aavpa, satira, a lizard. 

Igneous Rocks. All rocks, such as lava, trap, and granite, 
known or supposed to have been melted by volcanic heat. 

Induction. 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. 

Infusory Animalcules. 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. 

Inspissated. Thickened. Etym., spissus, thick, 
Ikvertebrated Animals. Animals which are not furnished 

with a back-bone. For a further explanation, see ^' Verte- 

brated Animals." 

Isothermal. 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 laos, isos, equal, and 
StepfiT]} 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. 



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447 



Lacustrine 



KiMMERiBOE Clat. A thick bed of clay, consUtuUng a member 
"^ of the Oolite Group. See Table L, H, Vol. IV. p. 303 So 

called because it is found well developed at Kimmendge m 

the isle of Purbeck, Dorsetshire. 

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Belonging to a lake. Etym., lacus, a lake. 

T AMANTixE. 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. ^ 

L.MEi..xFKK0tis. Having a structure consisting of thm plates or 

leaves like paper. ' Ety^., lamella, the diminutive of lamrna, 

plate, and fero, to bear 

Lamina. 



Latin for plates ; used in geology, for the smaller 



layers of which a stratum is frequently composed. ^ 



Landslip. 



DSLir A portion of land that has slid down m conse- 
nuence of disturbance by an earthquake, or from bemg un- 
dermined by water washing away the lower beds wh.ch 

Lapidifying process. Conversion into stone. 
Etym., lapis, stone, and jio, to make. 



supported it, 
Lapidification 



Lafilli. 

Lava. 

Leucite. 



Lias. 



Small volcanic cinders. Lapillus, a little stone. 
The «tone which flows in a melted state from a volcano. 
A cimnle mineral found in volcanic rocks, crystallized, 
and of a white colour. Etym., Xemos, leucos, white. 

A 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. -,,.,.,. A 

LiGMrEa.ous. A term applied to insects which destroy wood. 

Etym. , lignum, wood, and perdo, to destroy. 

Wood converted into a kind of coal. Etytn. , lignum, 

0D0.1X 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 d.ssolved. 
Etym. , Kidos, Vdhos, stone, and Se/xco, demo, to build. 
LiTHOGKNOUS Po.YPS. Animals which form coral. ^ 

LixHooHAPHic STO.K. A slaty compact limestone, of a yellowish 
colour and fine grain, used in lithography, which is the art of 



Lignite. 
wood. 

LiTHODOMI. 



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GLOSSARY. 



drawing upon and printing from stone. Etym., XtOoSy lithos, 
stone, and ypci<pw, grapho, to write. 

LiTHoiDAL. Having a stony structure. 

LiTHOLOGicAL. A term expressing the stony structure or charac- 
ter of a mineral mass. We speak of the lithoiogical character 
of a stratum as distinguished from its zoological character. 
Etym,, AiOos^ Ethos, stone, and Xoyos, logos, discourse. 

LiTHOPHAGi. Molluscous animals which form holes in solid stones. 

See "Lithodomi." Etym., XidoSy lithosy stone, and (l>aj€iu, 
phageiriy to eat. 

LiTHopHYTES. The auimals which form stone-coral. 

Littoral. Belonging to the shore. Etym.y littus, the shore. 

Loam. A mixture of sand and clay, 

LopHioDON. A genus of extinct quadrupeds, allied to the Tapir, 
named from eminences on the teeth. 

Lycopodiace^. Plants of an inferior degree of organization to 
Coniferse, 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 coniferse. 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. 

Lydfan Stone. Flinty slate ; a kind of quartz or flint, allied to 
hornstone, but of a greyish black colour. 

Macigno. 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. 

Magnesian Limestone. An extensive series of beds, the geolo- 
gical position of 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 1. L, Vol. IV. p. 305. 

Mammiferous. Mammifers. Animals which give suck to their 
young. To this class all the warm-blooded quadrupeds, and 
the cetacea, or whales, belong, Ety^n., mamma, a breast, 
Jero, to bear. 



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GLOSSARY. 



449 



Mammillary 



^, A surface which is studded over with rounded 

prdections. i?fym., mammtYZa, a little breast or pap. 
CMOTH. An extinct species of the elephant {E. primigemus), 
of which the fossil bones are frequently met with in various 



Mammoth. 



countries 



The name is of Tartar origin, and is used m 



Siberia for animals that burrow under ground. 



Manati. 



One of the cetacea, the sea-cow or lamantiae {Tri^ 

chechus manatus^ Lin.) 
M.a.. A mixture of clay and lime ; usually soft, but sometimes 

hard, in which case it is called indurated marl. 
Makshpial Animals. A tribe of quadrupeds having a sack or 

pouch under the belly, in which they carry their young. Ihe 

kangaroo is a well-known example. Etym., n.arsup^ur>^, a 

MAsx'or; A genus of fossil extinct quadrupeds alHed to the 
elephants ; so called from the form of the hind teeth oi grmd 
ers. which have their surface covered with corneal mam- 
millary crests. Etym. , luacrros, mastos, pap, and o^m odon, 

MatITx^'k a 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. 

Mkch1::1^0:L, Kocks o. nocks composed of sand, peb- 
We" or fragments, are so called, to distinguish them from 
those of a uniform crystalline texture, which are of chemical 

ns^ A genus of marine radiated animals, without shells ; 
so clued because their organs of motion spread out like the 
snaky hair of the fabulous Medusa. _ , . ,1,, 

MECAi-osLaus. A fossil gigantic amphibious animal of the 
saurian or lizard and crocodile tribe. Etym., (.eyaM, regale, 
great, und aavpa, saura, lizard. . . 

MegIthkuium. a fossil extinct quadruped, resembhng a gigantic 

Etym., I^eja, mega, great, and Ovp^ov, thenon, wild 

.STOMA. A genus of Me..stomacea, an order of exotic 
Plants of the evergreen tree, and shrubby kinds. Etym 
'XJ lelas, black, and cr.o,«, stoma, mouth ; because the 



origin 
Medusa. 



sloth, 
beast. 
Melastoma. 



fruit of one of the species stains the lips- 



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GLOSSARY. 



Mesotyfe. a simple mineral, white, and needle-shaped, one of 

the Zeolite family, frequently met with in the trap-rocks. 
METAMORrHic 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 diflferent mineral. The brilliant scales in 
granite are mica, Etym,^ mico^ to shine. 

Mica-slate, Mica-schist, Micaceous Schistus, 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. 

Miocene. See an explanation of this term, Vol. III. p- 370. 

MoLAssE. 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, 
inolle, soft. ' 

MoLLuscA, Molluscous Animals. Animals, such as shell-fish, 
■ which, being devoid of bones, have soft bodies. Etynu, 



Tnollis, soft. 



\ 



Monad. The smallest of visible animalcules, spoken of by BufTon 

and his followers as constituting the elementary molecules of 

organic beings. 
Monitor, An animal of the saurian or lizard tribe, species of 

which are found in both the fossil and recent state. 
MoNocoTYLEDONous. A grand division of the vegetable kingdom 

(including palms, grasses, lilaceee, &c.), founded on the plant 

having only one cotyledon, or seed lobe. Etym,, fiovos, 7}ionos, 
single. 

MosCHUs. 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. 



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451 



MuLTiLOCULAR. Many-chambered, a term applied to those fhells 
which, like the nautilus, ammonite, and others, are diviaea 
into many compartments. Et^/m. , multus, many, and loculus, 

a partition. i- u 

Muriate of Soda. The scientific name for common culinary salt, 
because it is composed of muriatic acid and the alkali soda. 

A family of tropical monocotyledonous plants, in- 



MUSACE^- 



cludinc the banana and plaintains 
MuscHELKALK. A limestone which, in geological position, belongs 



formation 



to the red sandstone group. _ i i -p 

found in England, and the German name is adopted by i^n- 
glish geologists. The word means shell-limestone, l^tym^. 
muschel, shell, and kalkstein, limestone. See Table L, K, 
Vol. IV. p. 305. 

A very thin, volatile, inflammable, and fluid mineral 



Naphtha. 



5 



substance, of which there are springs in many countries, 
particularly in volcanic districts. 
Nenuphar. A yellow water-lily. 

New Red Sanbsxone. A series of sandy and argillaceous strata 
the predominant colour of which is brick-red, but contammg 
por ions which are of a greenish grey. These occur often 
- inspots 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 
n sian limestone. See Table I., K. Vol. IV. p. 304. 

A rounded irregular-shaped lump or mass. Etym. 

diminutive of nodus, knot. 
NormI. Groups. Groups of certain rocks taken as a rule or 



Nodule. 



standard. Etym., norma, rule or pattern. 



Nucleus. 



A solid central piece, around which other matter is 



collected. The word is Latin for kernel. 



NUMMULI'IES. 



MULiTES. An extinct genus of the order of molluscous, 
animals called Cephalopoda, of a thin lenticular shape in. 
ternally divided into small chambers. Etym.,nur^p Latin 
friney, and K^Oos, Utkos, stone, from its resemblance to a 



com. 



A volcanic product, or species of "lava, very like com- 
mon green bottle-glass, which is almost black in large masses, 



Obsidian. 



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GLOSSARY. 



A great inundation nientioned in fabulous 



but semi-transparent in tiiin 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. 

Ogygian Deluge. 

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. k 
Old Red Sandstone. A stratified formation immediately below 

the Carboniferous Group, and sometimes classed with it. 

See Table I., N, Vol. IV. p. 306. 
Olivine. An olive-coloured, semi-transparent, simple mineral, 

very often occurring in the form of grains and of crystals in 

basalt and lava. 

Oolite, Oolitic. 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. Uti/m,, mv, oon, egg, and XlOos, lithos, stone. 

Opalized Wood. Wood petrified by siliceous earth, and ac- 
quiring a structure similar to the simple mineral called 
opal. 

OpHiDious Reptiles. Vertebrated animals, such as snakes and 

serpents. Etym,, ocpis, ophis^ a serpent. 
Organic Remains. The remains of animals and plants (organ- 



^ 



ized bodies) found in a fossil state. 



Orthocerata, or Orthocer^. An extinct genus of the order of 

molluscous animals, called Cephalopoda, that inhabited a 

long-chambered conical shell, like a straight horn. Efym., 

opQoSy ortkos, straight, and Kepas, ceras, horn. 
Osseous Breccia. The cemented mass of fragments of bones of 

extinct animals found in caverns and fissures. Osseus is a 

Latin adjective, signifying bony. 
Osteology. That division of anatomy which treats of the bones ; 

from oo-reoy, osteon, bone, and \oyos, logos, a discourse. * 
Outliers. When a portion of a stratum occurs at some distance, 

detached from the general mass of the formation to which it 



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belongs, some practical mineral surveyors call it an outlier, 
and the term is adopted in geological language. 

Ovate. The shape of an egg. Etym.y ovum, egg. 

Ovipositing. The laying of eggs. 

Oxide. The combination of a metal with oxygen ; rust is oxide 

of iron. 
Oxygen. 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. 

Pachydermata. An order of quadrupeds, including the elephant, 
rhinoceros, horse, pig, &c., distinguished by having thick 
skins. Eti/m., irax^s , pachus, thick, and Sep/xa, derma, skin, 

or hide. 

Pachydermatous. Belonging to pachydermata. 

Pal^otherium, Paleothere. a fossil extinct quadruped, be- 
longing to the order Pachydermata, resembling a pig, or 
tapir, but of great size. Etym., TraAatos, palaios, ancient, 

and b7)piov, therion, wild beast. 

Paleontology. The science which treats of fossil remains, both 
animal and vegetable. Etym., iraXaios, pelaios, ancient, 
ovra, onta, beings, and Koyos, logos, a discourse. 

Pelagian, Pelagic. Belonging to the ^^i? sea. Etym,,pela- 



gus, sea, 



^ 

Peperino. An Italian name for a particular kind of volcanic 
rock, formed, like tuff, by the cementing together of volcanic 
sand, cinders, or scoriae, &c. 
Petroleum. A liquid mineral pitch, so caUed because it is seen to 
ooze like oil outof the rock. Etym, , petra, rock, and oleum, oil. 
Ph^nogamous or Phanerogamic Plants. A name given by 
Linn^us to those plants in which the reproductive organs 
are apparent. Etym., ^oLv^pos, phaneros, evident, or <paiv<a, 
phaino, to show, and ya^ios, gamos, marriage. 
Phlegr^an Fields. Campi Phlegraei, or " the Burnt Fields." 
The country around Naples, so named by the Greeks, from 
the traces of igneous action every where visible. 
Phonolite. See « Clinkstone." 
Phryganea. a genus of four-winged insects, the larvae of which, 

called caddis worms, are used by anglers as a bait. 
Physics. The department of science which treats of the proper- 



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ties of natural bodies, laws of motion, &c. ; sometimes called 
natural philosophy and mechanical philosophy. Etym,, 
(j)vo'is, pilosis, nature. 

Phttology, Phytological. The department of science which 
relates to plants — synonymous with botany and botanical. 
Etym.y ^VToVj phyton, plant, and Xoyos^ logos, discourse. 

Phytophagous. Plant-eating. Etym.^ (pvr oj/ , phyton, plant, and 
^ary^iVy phageiriy to eat. 

Pisolite. A stone possessing a structure like an agglutination 
of pease. Etym, , iricrov, pison, pea, and KiQoSy lithos, stone. 

PisTiA. Vol. III. p. 42. The plant mentioned by Malte-Brun 
is probably the Pistia Stratiotesy a floating plant, related to 
English duck-weed, but very much larger. 

Pit Coal. Ordinary coal ; called so because it is obtained by 
sinking pits in the ground. 

PiTCHSTONE. A rock of a uniform texture, belonging to the 
unstratified and volcanic classes, which has an unctuous ap- 
pearance like indurated pitch. 

Plastic Clay. One of the beds of the Eocene Tertiary Period 
(see Table 1., 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,^ i^Xacrao), plasso, to form or 
fashion. 

Plesiosaukus. a fossil extinct amphibious animal, resembling 
the saurian, or lizard and crocodile tribe. Etym., ttXtjctloj/, 
pleswuy near to, and savpa, saura, a lizard. 

Pliocene. See explanation of this term, Vol. III. p. S68. 

Plutonic 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. 

Polyparia. Cohals. a numerous class of invertebrated 
animals, belonging to the great division called Radiata. 

Porphyry. 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 



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GLOSSARY. 



455 



through a base of other mineral composition. Etym., 
Trop(pvpa, porphyra, purple. 
Portland Limestone, Portland Beds. A series of limestone 
strata, belonging to the upper part of the Oolite Group (see 
Table I., H, Vol. IV. p. 303. )5 found chiefly in England 
in the Island of Portland on the coast of Dorsetshire. '^^- 



The 



oreat supply of the building stone used in London is from 



these quarries 



PozzuoLANA. 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. 

Precipitate. Substances which having been dissolved in a 
fluid, are separated from it by combining chemically and 



formin 



This 



process is the opposite to that of chemical solution. 



Producta. An extinct genus of fossil bivalve shells, occurrmg 
only in the older secondary rocks. It is closely allied to the 
living genus Terebratula. 

Pubescence. The soft hairy down on insects. Etym., pithesco, 

the first growth of the beard. 
PuDDiNGSTONE. See " Conglomerate." 



Pu>IICE. 



A light spongy lava, chiefly felspathic, of a white colour, 
pToduced 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 
slass. The word comes from the Latin name of the stone, 



puviex 



PuRBECK Limestone, Pukbeck Bebs. Limestone strata belong- 
ing to the Wealden Group. See Table I. G, Vol. IV. p. 303. 

Pyrites ( 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 ^vp, 
pyr, fire ; because, under particular circumstances, the stone 
produces spontaneous heat, and even inflammation.^ 

PvROMEXER. An instrument for measuring intense degrees of 

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QuABRUMAKA. The order of mammiferous animals to which apes 
belong. Etym,^ quadrus, a derivative of the Latin vrord for 
the number four, and manus, hand ; the four feet of those 
animals being in some degree usable as hands. 

Q,u A- QUA-VER SAL Dip. 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-qud versitm, on every 

side. 
Quartz. A German provincial 



A German provincial term, universally adopted m 
scientific language for a simple mineral composed of pure 
silex, or earth of flints : rock-crystal is an example. 

4 

Red Marl. A term often applied to the Nevr Red Sandstone, 
which is the principal member of the Red Sandstone Group. 
See Table I., K, Vol. IV. p. 304. 

Reticulate. A structure of cross lines, like a net, is said to be 
reticulated, from rete, a net. 

Rock Salt. 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 rocAr-salt. 

RuMiNANTiA. Animals which ruminate or chew the cud, such 
as the ox, deer, &c. Etym., the Latin verb rumino, meaning 
the same thing. 

Saccharoid, Saccharine. When a stone has a texture resem- 
bling that of loaf-sugar. Etym., (raKXo^p, sacchar, sugar, and 

€(5os, eidoSy form. 
Salient angle. 

In a zigzag 

line, a a ar^ 

the sali ent 

angles, b b ■ 

the re-entering angles- Etym.j satire, to leap or bound for- 
ward. 
Salt Springs. Springs of water containing a large quantity of 

common salt. They are very abundant in Cheshire and 
Worcestershire, and culinary salt is obtained from them by 
mere evaporation. 
Sandstone, Any stone which is composed of an agglutination 




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GLOSSARY. 



457 



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of grains of sand, whether calcareous, siliceous, or of any 
other mineral nature. 
Saurian. Any animal belonging to the lizard tribe. Etym.y 

aavpa, saura, a lizard. 
Schist is often used as synonymous with slate ; but it may be very 
useful to distinguish between a schistose and a slaty structure . 
The o-ranitic or primary schistSy as they are termed, such as 
gneiss, mica-schist, and others, cannot be split into an inde- 
finite number of parallel laminae, like rocks which have a true 
slaty cleavao-e. The uneven schistose layers of mica-schist 
and gneiss are probably layers of deposition which have 
assumed a crystalline texture. See " Cleavage." Eti/m,, 
schistus, adj. Latin; that which may be split. 

Schistose Rocks. See " Schist," 

Scoria. "Volcanic cinders. The word is Latin for cinders. 

Seams. Thin layers which separate two strata of greater magni- 
tude. 

Secokdary Strata. 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 L 

Vol. IV. p. 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. 

Sedimentary Rocks, are those which have been formed by their 
materials having been thrown down from a state of suspen- 
sion or solution in water. 

Seeenite, Crystallized gypsum, or sulphate of lime — a simple 
mineral. 

Septaria. 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. 



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GLOSSARY. 



Shale. A provincial term, adopted by geologists, to express an 

indurated slaty clay. Etym., German schalen, to peel, to split. 
Shell Marl. A deposit of clay, peat, and other substances 

mixed with shells, which collects at the bottom of lakes. 
Shingle. The loose and completely water-worn gravel on the 

sea-shore, 
SiLEX. The name of one of the pure earths, being the Latin 

word for Jlint, 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. 
Silica. One of the pure earths. Etym,, silex, flint, because 

found in that mineral. 

Silicate. A chemical compound of silica and another substance, 
such as silicate of iron. Consult elementary works on che- 
mistry. 

Siliceous. Of or belonging to the earth of flint. * Etym., silex, 
which see. A siliceous rock is one mainly composed of silex. 

SiLiciFiED. Any substance that is petrified or mineralized by 

siliceous earth. 

Silt. 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. 

Simple Mineral. 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. 

Slate. See " Cleavage" and '' Schist." 

SoLFATARA. A volcauic vcut from which sulphur, sulphureous, 
watery, and acid vapours and gases are emitted* 

Sporules. The reproductory corpuscula (minute bodies) of 
cryptogamic plants. EtyTn, ^ tnropa, spora^ a seed. 

Stalactite. When w^ater holding lime in solution deposits it as 
it drops from the roof of a cavern, long rods of stone hang 



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GLOSSARY. 



k59 



down like icicles, and these are called stalactites. Etym., 

(TTaXa^w, stalazOi to drop. 
Stalagmite. 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 craXayiJLa, stalagmay a drop, in opposition to sta-, 

F 

lactite, which see. 
Statical Figure. The figure which results from the equilibrium 

of forces. From (TTaros, statos^ stable, or standing still. 
Sternum. The breast bone, or the flat bone occupying the 

front of the chest. 
Stilbite. a crystallized simple mineral, usually white, one of 
the Zeolite family, frequently included in the mass of the 

w 

trap rocks. 

Stratified. Rocks arranged in the form of strata^ which see. 

Stratification. An arrangement of rocks in strata, which see. 

Strata, 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. 

Strike. 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. 
SuBAFENNiNEs. 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. 



V, 



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. 

Synclinal Axis. See " Anticlinal.'* Etyvuy <Tvy, syn, together, 
and K\fw, clinoy to incline. 

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GLOSSARY. 



Talus. When fragments are broken off by the action of the 
weather from the face of a steep rock, as they accutnulate 
at its foot, they form a sloping heap, called a talus. The 
term is borrowed from the language of fortification, vs'here 
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. ' 
Tarsi. The feet in insects, which are articulated, and formed 

of five or a less number of joints;, 
Tertiary Strata. A series of sedimentary rocks, with charac- 
ters which distinguish them from two other great serie 

which lie beneath 



of strata — the secondary and primary 
them. 



Testacea. 



EtyTTi 



testa, a shell, such as snails, whelks, oysters, &c. 

Thermal. Hot. Etym., Srepfios, thermos, hot. 

Thermo-electricity. Electricity developed by heat. 

Thin out. 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. 

Trachyte- 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 rpaxvs, trachusy rough, because the rock 
has a peculiar rough feel. 

Trap and Trappean Rocks. Volcanic rocks composed of felspar, 
aua"ite, 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 basaltj amygdaloid, dolorite 
o-reenstone, 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. 345. 



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Travertin. A concretionary limestone, usually hard and semi- 

■ystalline, deposited from the water of springs holding lime 
in solution. — Eti/7n. 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. 

Teophi, of Insects. Organs which form the mouth, consisting of 
an'upper and under lip, and comprising the parts called 
mandibles, maxillae, and palpi. 

Tufa, Calcakeoits. A porous rock deposited by calcareous 
waters on their exposure to the air, and usually contaming 
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. 

Tufa, Volcanic. See " Tuff." 

TuFACEOUS. A rock with the texture of tuff or tufa, which see. 

Tuff or Tufa, Volcanic. An ItaUan name for a variety of 
volcanic rock of an earthy texture, seldom very compact, and 
composed of an agglutination of fragments of scoriae and 
loose matter ejected from a volcano. 

Turbinated. Shells which have a spiral or screw-form structure. 

Etym., turbinatus, made Hke a top. 



Unconformable 



See " Conformable. 



ty 



Unoxidized, Unoxidated. Not combined with oxygen. 

Veins, 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- 



The 



bone, as the mammalia, birds, reptiles, and fishes 
separate joints of the back-bone are called vertebrce, from the 
Latin verb verto, to turn. 
Vesicle. A small, circular, inclosed space, like a little bladder. 
Etym., diminutive of vesica, Latin for a bladder. 






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462 



GLOSSARY. 



Vitrification. The conversion of a body into glass by heat- 
VoLCANic Bombs. 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. 
Volcanic Foci. The subterranean centres of action in volcanos, 
where the heat is supposed to be in the highest degree of 

energy. 

Wacke. a rock nearly allied to basalt, of which it may be re- 
garded as a soft and earthy variety. 

F 

Zeolite. 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 ^eco, %eo, to boil, and KiQoSj litkos, stone. 

Zoophytes. 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, Eti/m,y fwoy, zoon, animal, and ipvroi^j phyton^ 
plant. 



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END OF THE i'lRST VOLUME 



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Printed bv A. Spottiswoode, 
New-Street- Square. 



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