Illustrations of the Huttonian theory of the earth

cs

a,

ILLUSTRATIONS

OF THE

HUTTONIAN THEORY

OF THE EARTH.

By JOHN PLAYFAIR,
F. R. 5. EDIN. AND PROFESSOR OF MATHEMATICS
IN THE UNIVERSITY OF EDINBURGH.

ii

| Nunc naturalem caufam querimus et afiduam, non raram et
Sortuitam.

SENECA,

EDINBURGH:

PRINTED FOR CADELL AND DAVIES, LONDON, AND
WILLIAM CREECH, EDINBURGH.

1802.

Entered in Stationers Balt.

Nerit & ĉo. ?
Printers, Edinburgh. 5

ADVERTISEMENT.

HE Treatife here offered to the Public,

was drawn up with a view of explain-
ing Dr Hutton’s Theory of the Earth in a
manner more popular and perfpicuous than
is done in his own writings. The obfcu-.
rity of thefe has been often complained of ;
and thence, no doubt, it has arifen, that fo
little attention has been paid to the inge-
nious and original fpeculations which they
contain.

THE fimpleft way of accomplifhing the
object propofed, feemed to be, to prefent a
General Outline of the Syftem, in one con-
tinued Difcourfe ; and to introduce after-
wards, in the form of Notes, what farther
Elucidation any particular fubje@ was
thought to demand. Through the whole,
I have aimed at little more than a clear ex-
pofition of fas, and a plain dedudtion of
the conclufions grounded on them; nor
fhall I claim any merit to myfelf, if, in the -
order which I have found it neceflary to
adopt, fome arguments may have taken a

å 2 new

iv ADVERTISEMENT.

new form, and fome additions may shave
been made to a fyftem naturally rich in the
number and variety of its illuftrations.

Or the qualifications which this underta-
king requires, there is one that I may fafely
fuppofe myfelf to poflefs. Having been in-
{tructed by Dr Hutton himfelf in his theory
of the earth; having lived in intimate friend-
{hip with that excellent man for feveral
years, and almoft in the daily habit of dif-

culling the queftions here treated of; [have —

had the beft opportunity of underftanding
his views, and becoming acquainted with
his peculiarities, whether of expreffion or of
thought. Inthe other qualifications necef-
fary for the illuftration of a fyftem fo ex-
tenfive and various, I am abundantly fen-
fible of my deficiency, and fhall therefore,
with great deference, and confiderable an-
xlety, wait that decifion from which there is
no appeal.

EDINBURGH COLLEGE,
Ift March 1802. t

OO EEEO

TABLE

OF

SON 1 EN T S.

INTRODUCTION. Objeé of a Theory of the Earth.
Divifion of minerals into Stratified and Unflratified.
Page 1.

SECTION I.
PHENOMENA PECULIAR TO STRATIFIED BODIES.
1. Materials of the Strata. Page 4

Prefent ftrata compofed of the remains of more ancient
rocks, § 1. Proofs from calcareon ftrata, § 2.—from
filiceous, § 3.—from argillaceous, § 4.—from bitumi-
nous, § 5,6. Abfence of organized remains from the ©
ftrata called primitive, not univerfally true, § 8, 9.
Term Primary fubftituted for Primitive. Compofition
from the materials of more ancient rocks, § ro.

T 2. Confolidation of the Strata. p. I5

Confolidation, what, § Ir. Objedions to aqueous con-

folidation, § 12, 13, 14. Compreffion affe&ts the ac-
tion of fire on bodies, § 15, 16, 17. Igneous confoli-
dation of minerals proved from foffil wood, § 19.—
from the flints in chalk, § 20.—from fandftone, § 27.—

from

vi | CONTENTS.

from the calcareous ftrata, § 23, 24, 25.—from the ar-
gillaceous, § 26, 27.—from the bituminous, { 28, 29.
—from the faline, § 32. Salt-mines in Chethire.
Trona of Africa, $ 34, 35.

3. Pofition of the Strata. Page 40

Strata formed at the bottom of the fea, § 36. Appa-
rent elevation not produced by the retreat of the fea,
§ 37. Strata, horizontal, when formed, § 38, 39. Dif-
turbance of the ftrata proved from their inclined pofi-
tion, § 40, 41, 42.—from fhifts, &c. § 42. Shifts of |
different dates, 7b. Difturbance of the primitive ftrata
vifible at their junétion with the fecondary, § 43, 44.
This difturbance produced by a force dire€ted up-
ward, § 45,46. This force the effet of fubterra-
neous heat, § 47, 48. :

ra SECTION II.
PHENOMENA PECULIAR TO UNSTRATIFIED BODIES.
1. Metallic Veins. pP. 57

Veins defined. They contain fubftances that were once
in fufion, § 49, ṣo. Metallic veins, native metals, &c.
§ 51. Native copper, § 52. Manganefe, § 53. Frag-
ments of rocks included in veins, § 55. Shifting and
heaving of veins, § 56, 57. Veins of different dates,
§ 58. Stratification not found in veins. Coating of
the fides, what, § ṣọ., Metallic veins moft common
in primitive ftrata, but not confined to them, § 60.

2. Whinftone. `

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4

terra.

DIES.
p. 57

> once

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CONTENTS. yä

2. Whinftone: Page 66 ©

Enumeration of ftones of this genus, § 61. Whin, whe-

ther in veins or in mafles, refembles lava, § 62. Is
a fubterraneous lava, § 63. Columnar ftructure an
argument for fufion, § 64. Not produced by drying,
§ 65. Whinftone penetrated by pyrites, § 66. In-
duration of the ftrata in contaé&t with whin, § 67. Coal
charred by whinftone veins, § 68. Difturbance of
the ftrata by whinftone veins, § 69. Phenomena of
whin interpofed. between ftrata, § 7°, 71- Tranfition
from whin to ftrata not gradual, § 72. Agates and
chalcedonies in whinftone, § 74. This ftone melted
and reproduced from fufion by Sir James Hall, § 75.
Mineral alkali found init by Dr Kennedy, 7b. Whin-
ftones of different formation, § 76. Porphyry a fpecies
or variety of whinftone, § 77:

3. Granite. p. 82

Granite defined. Exifts in maffes and veins, § 77 The

bafis of other rocks, § 78. Its original fluidity inferred
from the cryftallization of its parts, } 79- Its fufion,
from the ftruture of the Portfoy granite, § 80, 81.—
from granite veins, § 82. General conclufion as to
the igneous origin of minerals, § 83, 84, 85. Adual
exiftence of fubterraneous heat known from hot {prings,
volcanoes, earthquakes, § 86. Volcanic fire feated
deep under the furface, § 87. Subterraneous heat not
accompanied by burning, § 88, 89. Tran{miffion of
fubterraneous heat, fo as to produce hot f{prings, &c.

§ 90, 91.

a 4 SECTION

Vill CONTENTS.

SECTION III.

PHENOMENA GOMMON TO STRATIFIED AND UN-
STRATIFIED BODIES. Page o7 |

Chemical agents which produce the decompofition of mi-
neral fubftances at the furface, § 92, 93. Mechanical
agents, § 95, 96. Proofs of wearing from the fea-fhore,

§ 97,98. Rivers, § 99, 100. Defiles among mountains, —
§ 102. Supply of the foil from the decompofition of
rocks, § 103. Gravel in the foil, § 104, r05. Gold
found in the foil, § 106. Tin, § 107. Proofs of wafte
from mountainous countries, § 108, 109. Structure
of valleys, § 111. Tranfportation of ftones, § 112.
Neareft meafure of the wafte, § 113. General re-

marks, § 114, 115. No production of minerals on
the furface, § 116. Reproduction at the bottom of 4
the fea, § 117. Continued fyftem of decay and reno-
vation, § 118. Defence againft the charge of impie-
ty, «19. Antiquity and order of the revolutions of |
the globe, § 120, 121, 122, 123, 124. Confiftency |
with the Sacred Writings, § 125. Scope of this theory

of the earth diftinguifhes it from others; beauty and
extent of its views, § 126. New faéts, § 124. |
Comparifon of this theory with that of Buffon, § 129. .
of Lazzaro Moro, § 130. Plutonic fyftem, § 131. Di- |
ftinguihed hy the principle of compreffion, § 132. — |
Explains the oblate figure of the earth, 74. Prejudi- |
ces againit this fyftem, § 133. What may be expett-
ed from the progrefs of fcience, § 134.

NOTES. .

CONTENTS. ig

NOTES AND ADDITIONS.

Nore 1.—Origin of Calcareous Earth.
Page 143
Dr Hutton’s opinion on this fubject accurately ftated,
§ 134. Mifreprefented by Kirwan, § 135.

Nore 11.—Origin of Coal. P- 147

Vegetable origin of coal. Opinion of Buffon, § 136.—
of Arduino, zb.—of Lehman, § 137. Diftindtion at-
tempted between wood-coal and mineral-coal, § 138.
Not of different origin, but gradually pafs one into

* the other, § r39. Bovey coal, § 140. Kirwan derives
the matter of mineral-coal from the decompofition of
hornblende, &c. 142. Abfurdity of this fuppofition,
$ 143,144, 145,146. .

Nore 111.—Primitive Mountains.
p- 160
Lehman introduced the term Primitive mountains, § 148.
Suppofed more ancient than organized bodies, § 149.
Stratification of primitive mountains denied by Pini,
and maintained by Sauffure, § iso.

Nore rv.—Primary Strata not primitive.
p- 163
Shells found in primary rata, § 151. Sandftone in
primary mountains, § 152. Quartzy fand in the
` {chiftus of the Grampians, 76. Rocks difiinguifhed
j by

g CONTENTS.

\

by Werner into three orders, § 153. Objeĉtions a

this arrangement, § 154.

Nore v.—Tranfportation of the materials of the

Strata. Page 171

The tranfportation of materials, obje&ed to by the Nep-

tunifts, is implied in their own fyftem, § 155, 156,

157. Proofs of great tranfportation from the animal
and vegetable remains, found in rocks, § 159.

Nore vi.—Kirwan’s Notion of Precipitation.
p. 180

Difficulty of precipitating the materials diffolved in the

chaotic fluid, § 161. Infufficiency of the explanatiog —

attempted, 7d.

Nore vit.—-Compreffion in the Mineral Regions.

p. 181
Effets afcribed to compreflion by Newton, compared
with the effects afcribed to it in this theory, § 162.
Fallacy of Kirwan’s argument concerning the fufion
of Carrara marble, § 164, 165. Heat of the mineral
regions may be fupported without fuel, § 166. Quo-
totation from Newton’s ort ib; .General re-
marks, § 168.

Nore vii1.—Sparry Structure of Calcareous Pe-
trifactions. p. 140

Sparry and organic ftructure co-exift in certain foils, —

§ 170. Sparry and ftratified ftru@ture co-exift in gneifs,
marble, &c. § 17%

Not E

a

CONTENTS. xi

Nore 1x.—Petroleum, &c. Page 194

Petroleurh, &c. from the diftillation of coal, { 172. Gra-
dation from petroleum to coal often met with, § 173.
Conneétion of amber and coal, § 174. Why mines
of blind coal have not always petroleum mines near

them, § 175.

Note x.—The Height above the Level of the
sea, at which Marks of Aqueous Depofition
are found. p. 199

Thefe marks confift either in ftratification or in marine
objects, § 176. The marks of ftratification obferved,
414,939 feet above the fea, § 177. Shells in Peru,
14,190, § 178. Kirwan’s miftake concerning thefe
fhells, § 179. His error fimilar to Vonrairsg’s, § 180.

Note x1.—Fracture and Diflocation of the
Strata. p. 204

Slips, § 181. Rib of limeftone in a flip near Hudders-
field, § 182, 183. Singular fraéture of pudding-ftones
at Oban in Argylefhire, § 184. Similar phenomena
obferved by Sauffure between Nice and Genoa, tå.
Remarks on it, § 185.

Nore x11.--Eleyation and Inflexion of the Strata.
p. 209

Junction of primary and fecondary ftrata, § 186. Brec-
cia incumbent on the primary, § 187. Junction of the
primary and fecondary ftrata: At Torbay in Devon-
fhire

zii CONTENTS.

fhire, § 189,—coaft of Berwickthire, $ 190,—Cullen in
Banffshire, § 192,—Ardencaple in. Dumbartonfhire,
Arran, &c, § 193,—Pembrokeshire, $ 194,—Jed-
burgh, § 195,—Ingleburgh in Yorkfhire, § 196,-
Cumberland, § 197. Inflexion of the ftrata, § 198,
Remarkable inftances in the Alps and Pyrenees,
§ 199, 200,—on Benlawers in Perthhhire, $ 20pm

coaft of Berwickfhire, 7.—Plymouth, § 202. Stra-
ta fuffering fuch inflexions have been foft and duc-
tile, § 203. General property of thefe inflexions,
$ 204,205. Uniform ftretch of the primary ftrata,
§ 206. Inferences as to the nature of the elevating a
force, § 207. Imperfeion of other theories. Cry-
ftallization, 7b- Marks of undulæ in the fchiftus,
§ 208. Elevation of the ftrata a ftronghold of the
Huttonian theory, § 209. Elevation of the ftrata
enables us to fee far into the interior of the earth,

§ 210.

Nore x1i1.—Metallic Veins. Page 239

Specimens of native iron, § 211, 212. Margraaf ’s {pe-
cimen, § 213. Kirwan’s hypothefis, § 214. Increafe

of the fpecific gravity of native gold by fufion, no
argument againft its igneous origin, § 215. Speci-

mens of gold and filver fhooting through quartz, an
argument in favour of the Huttonian theory, § 217,

218. Proof in favour of the fame from chalce-
dony including calcareous fpar, § 219. Matter that
fills veins not from above or from either fide, $ 220.
Opinion of the Neptunitts, § 221. Suppofed fa& that
Veins are lefs rich as the depth increafes, § 222. No

marks of horizontal depofition in veins; their coating
differs

CONTENTS. xili

differs from ftratification, § 223. Neptunifts appear
to be mifled by the term Stratification, § 224, 225.
Veins heave or fhift one another, § 226. Waft force
employed for that purpofe, § 227. Veins of differ-
ent formation, § 230. Pieces of rock infulated in
veins, § 231. Suppofition that veins have been filled
by infiltrations, abfurd, 230. Lenticular veins, and

Pipe veins, § 233.

Nore x1v.—On Whinftone. Page 260

Whinftone, neither of volcanic nor aqueous formation,

§ 234. Zeolite and carbonat of lime included in
whinftone, but not in lava, zb. Not introduced by
infiltration, § 235. Difpofition of whinftone moun-
tains differs from that of ftreams of lava, § 236.
This argument firft employed by Mr Strange, § 237.
His general views of this fubje@, § 238. Ex-
planation of the regular ftru@ture of whinftone hills,
according to Dr Hutton’s ‘theory, § 239. Many hills

fuppofed to be extinguifhed volcanoes, are rocks of |

real whinftone that has flowed deep under the furface.
Vein of whinftone miftaken for a ftream of lava by
Faujas, § 240, 241. Submarine volcanoes of Dolo-
mieu, § 242, Objections to this theory, § 243, 244.
Dolomieu in another place contends for the aqueous
formation of bafaltes, $ 245. His arguments an-
fwered; alfo thofe of Bergman, § 247, 248. Ar-
gument of Werner for the aqueous origin of ba-
faltes, § 249. Remarks on the fuppofed gradual
tranfition of bafaltes to argillaceous {chiftus, § 250,
251. Of the fhells faid/to be found in bafaltes,

A Bees

xiv CONTENTS.

§ 252. Inftances from Portrufh in Ireland, and from
Cerigo on the coaft of Greece, 1d. and 253,—from the
Veronefe, § 254. Objections to the Neptunian for.
mation of whinftone, founded on the difference be. —
tween it and the contiguous ftratified rocks, § 2 Te
On the refemblance of the ftrata below and above cer-

tain mafles of whinftone, § 256, On the irregularity
of the thicknefs of thofe mafles, § 257. Wedge-form
maffes of whinftone included between ftrata, § 258.
Confequences of this wedge-form, § 259. Sandftone
fragments included in whin, § 260, 261. Bending
of the ftrata contiguous to whinftone, § 263. In.

duration, § 264, 265. Charring of coal by whin;
§ 266. Of the manner in which the bitumen may |
have been driven off by heat, § 267. Two kinds of -
foflil coke, § 268. Graduation into plumbago, 7. and
269. Only remaining objection obviated by Sir
James Hall’s experiments, § 270. .

Nore xv.—On Granite. Page 307

TE

Granite veins of two kinds. § 273. Veins of which the

communication with large mailes of the fame ftone is _
not vifib: At the ifle of Coll, in the Hebrides, § 274, |
—at Portfoy, § 275,—in Cornwall, § 276,—in Glen- |
tilt, § 277. Veins vifibly conneéted with larger maffes, |
Argument furnifhed by them in favour of this theo-
ry, § 278, 279. Impoflibility of their being formed
by infi raion, § 280. Veins of this kind in Arran,
$ 281,—Galloway, § 282,—fides of Loch-Chloney,
Invernefs-fhire, § 283,—-St Michael’s Mount, Corn-
wall, § 284. Fragments of {chiftus contained in gra-
nite, § 286. |

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2, Granite

hin
may
s of

CONTENTS. xv

2. Granite of Portfoy. Page 320

Defcription of this granite, § 28%, Pierre graphique.

of M. Patrin not perfetly the fame with that of Port-
foy, § 288. Quartz cryftallized in the pierre gra-
phique, § 289. Inftances of quartz cryftallized in
other granites. In that of St Agnes in Cornwall,
§ 290. Whether this cryftallization is only found in
fecondary granites, § 291.

3. Stratification of Granite. p. 326

Queftion ftated concerning the ftratification of granite,

§ 292. Remarkable examples of ftratifiéd granite
at Chorley Foreft, Leicefterfhire, and at Faffnet
Water in Berwickfhire, § 294. Stratification of
Mont Blanc, and the Aiguilles of Chamouni main-
tained by Sauffure, § 295, 266. Seems neverthelefs
doubtful, § 297. Inthe granite mountains of Arran
doubtful, § 299. Explanation of the ftratification of
granite in this theory, § 300. If granitic veins were
found proceeding from real granitic ftrata, they could
not be explained on the principles here laid down,
§ 301. No fuch veins have been difcovered, § 302.
Anfwer to an objeCtion made to the igneous-origin of
granitic mountains, § 303, 304. Of the proportion
of the earth’s furface occupied by granite rocks,
§ 305. Not exceeding a ninetieth part, § 3¢6—310,
Extent of granite in Scotland erroneoufly eftimated
by Dr Hutton, § 311. Amounts perhaps to a twenty-
fourth of the whole furface, § 312. Obfervations on
Mr Kirwan’s opinion, § 313.

NotE

xi CONTENTS.

Nore xvi.—Rivers and Lakes. Page 350

The rivers have hollowed out the valleys, § 314. ‘HW
luftration from the courfe of the Danube, § 345.
Courfes of many rivers retain marks of having confift.
ed of a feries of lakes, § 316, 317. Filling up and
draining of lakes, § 319. Inftances from the lakes in
Cumberland, § 320. Lake of Geneva, § 321. Lakes
in North America, 7b. Cataraéts, § 322. Difficul.
ties in explaining the generation and continuance of
lakes, exemplified in that of Geneva, § 32 3- Attempt
to refolve thefe difficulties, § 324, 325, 326, 327% |
All lake$ not equally fubjeé to them, § 328. Watt
ing of the land by the rivers, proved from the mouths .
of rivers on bold coafts, § 329. Examples from Corn- _
wall, § 330, 331.

Nore xvi. Remains of Decompofed Rocks. Pp. 371

Plain of Crau, § 333. Its gravel from the decompofition

of pudding-ftone, § 334. Same true of much of the
gravel in this ifland, § 336, 337. Mount Rigi in
Switzerland the remains of a body of pudding ftone,
§ 38. Meafure of the’ deftru€tion in the ftratified
rocks fometimes afforded by the unftratified, § 339,
340. Rate at which the elevation of mountains has

` been fuppofed to decreafe, § 341.

Nore xv111.—Tranfportation of Stones, &c.
p. 381

Gravel fmaller and rounder the farther from its native

place, § 342. Different fources of cailloux roulés,

§ 343s

CONTENTS. xvii

§ 343, 344° Stones that hayė begun their migration
before the cutting out of the prefent valleys, § 345.
Declivity neceffary to enable ftones to travel from
the top of Mont Blane to the top of Mont Jura,
§ 346. Granite from Mont Blanc found eaftward
in the valley of the Drance, § 347- Machinery em-
ployed by nature in tranfporting rocks, § 348, 349.
Inftances of tran{ported {tones of great fize,—from the
vicinity of Geneva, § 350, 351,—from the Ifle of
Arran, § 352. How gravity may contribute to the
mowing of large ftones, even when the declivity is
f{mall, § 353. Rocking-ftones, § 354. Stone in Bor-
rowdale,—in the valley of Urferen, § 355. Large
ftones are fomctimes the remains of veins, § 356. Of
the hypothefis of a debacle, § 357. Structure of val-
leys unfavourable to this hypothefis, § 358,359. Parti-
cularly of valleys clofe at the ends, § 360, 361. Whe-
ther the fuppofition of a debacle is neceflary to explain
the moving of large maffes of rock, § 363. Whether
the abrupt faces of bills indicate the exiftence of any
fudden torrent, &c. 364. Fact concerning the fteep
faces of the mountains in the fouth of Africa, § 365.
A fact ftated that would lead neceffarily to belief in g
debacle; no example of it has yet occurred, § 366.

Nore x1x.—Tranfportation of Materials by the

Q ag
wea. Page 413.

Of the manner in which the detritus of the land is fpread

out over the bottom of the fea, § 368, 369. Seas ren-
dered fhallower, § 370. Sand-banks, § 371. Great
fyftem of currents twaced in-the Atlantic, 4 372, 373-
How far this tranfportation of materials may affect the

b earth’s

xvii CONTENTS.

earth's diurnal motion, § 37553 76. Kirwan’s mifap.
prehenfion of Friĥ, and of Major Rennel, § 377378.
His miftake about the tides, 3 = aii about
the formation of fand-banks, § 38

i

Nore xx.—Inequalities of the Planetary Mo-
tions. Page 437

Thefe inequalities all periodical, § 384: Circumftances
on which this depends, § 385. Affinity of this con-
clufion to that which Dr Hutton has eftablithed with
re{pect to the changes at the furface of the earth, § 386.

Nore xxi.—Changes in the Apparent Level of
the Sea. P. 441

Relative level of the fea and land fubje@ to change,
§ 337. Proofs that it has funk, on the fhores of this
ifland, § 338,+-on the coafts of F rance and Flanders,
§ 289, 390,—on the theres of the Baltic, § 391. This
has not arifen from the deprefiion of the fea, but from
the elevation of the land, § 39°, 393. The furface
of the Hadriatic higher now than formerly, § 394,
395- Alfo of the Mediterranean, § 397. Irregulari-
ties in thefe changes, § 398, 399- Hypothefis of Frif,
that towards the equator the fea is every where rifing,
§ 490. Difproved, 2d. ' Conclufion, § 401.

Nore xx11.—Foflil Bones. p. 458

Ver geta sa animal remains contained in the foffil

k ing a om, § 402. Of thofe that are enveloped or pe-
riid with ne earth, § 404, 405. Of the
bones buried in the loofe earth, { 406. Bones in Si-

beria referred to the rhinoceros and the elephant, |

§ 407.

—

Rie

Phyfical caufe of the earth’s oblate figur

CONTENTS. xix

§ 407. Thofe on the Ohio doubtful, § 407, 408. Opi-
nion of CAMPER, § 409,—of Cuvier, § 410. Objec-
tions to the latter, 7b. Enumeration of five fpecies
of animals now extin@, § 411- Change in the ani-
mal and vegetable kingdom may account for bones
found in countries where no analogous fpecies now
exilts, § 413. Proofs that the animals whofe bones are

ry

- found in Siberia inhabited that country, § 414—416.

Note xxx111.—Geology of Kirwan and De Luc.

Page 477

Thefe authors have improperly drawn religion into

their quarrel with Dr Hutton, $ 418, De Luc writes
a hiftory of what befel the earth before the creation
of the fun, § 419. Remarks on Kirwan’s geological
writings, § 421, 422, 423, 424.

Norse xxiv.—Syftem of Buffon. P- 483

In what Buffon’s theory of the earth and Dr Hutton's

agree, and in what they differ, § 425, 426. Great me-
rit of Buifon, notwithitanding his errors, § 424,

Note xxv.—Figure of the Earth. P. 488

e not obvious
from its prefent condition, § 428. How explained
by the Neptunitts, $429. Examination of their fo-
lution, § 430 431. Contradi@ion implied in iG
§ 432. Infufficiency of Buffon’s explanation, § 433.
Of the principle on -which the oblatenefs of the
earth may be accounted for in Dr Hutton’s theo-
ry, § 434. Of the changes that would happen in
the figure of a terraqueous body like the earth, fup-

pofing

xk CONTENTS.

pofing it ever fo irregular, § 435, 436,437. Two
different caufes of change, ib. Ultimate figure, that by
which the caufes of change are beft refifted, § 438.
Spheroidal figure, never perfectly acquired, § 439.
Agreement of this theory with obfervation, § 440,
Probable extenfion of the fyftenr of wafte and reno-
vation to the other planets, § 441, 442. Confirmation
from the fyftem of Saturn, § 443, 444.

Nore xxvi.—Prejudices relating to the Theory
of the Earth. Page/5ro

Alleged by fome that a theory of the earth ought not at
prefent to be attempted, § 445. The quick fucceffion
of geological theories has partly arifen from their ob-
je&t being mifunderftood, § 446. A fucceffion of theo-
ries is often a continued approximation to the truth,

§ 447. The more various the phenomena of any clafs,

the greater the chance of difcovering their true caufe,
§ 448. Reafon to think that the leading faéts in geo-
logy are now known, $ 449,450. A tendency may
be obferved in geological fyftems to approach to one
another, and to the Huttonian, §. 451. Example from
that of Sauflure, § 452,—of Dolomieu, § 453, 454
The difcoveries of Dr Black were neceffary for ún-
derftanding the true theory of the earth, § 456. Ufe
of theory in matters of obfervation, § 457, &c.

ERRATA.

Page 44. line 4. from the bottom, for that read as
6

s 189. Jor appearanes. read appearances, f
— 464. —— Ay Jor D’Avzinton read Dausentow
eens 74 82 p ma TZ, aoe.

or adverfaries read adverfary

IL-f

ILLUSTRATIONS, to

Very little attention to the phenomena of
the mineral kingdom, is fufficient to con-

Vince us, that the condition of the earth’s fur-

face has not been the fame at all times that it is
at the prefent moment. When we obferve the

_impreffions of plants in the heart of the hardeft
rocks; when we difcover trees converted into

flint, and entire beds of limeftone or of marble

-compofed of fhells arid corals; we fee the fame
l individual in two ftates, the moft widely differ-

ent from one another; and, in the latter in-
ftance, have a clear proof, that the prefent land
was once deep immerfed under the waters of
the ocean. If to this we add, that many mafles
of rock, the mof folid and compact, confit of
no other materials but fand and gravel; that,
on the other hand, loofe gravel, fuch as is form-
ed only in beds of rivers, or on the fea-fhore,
now abounds in places remote from both: if
we reflect, at the fame time, on the irregular

A. and

: ILLUSTRATIONS OF THE

and broken figure of our continents, and the
identity of the mineral ftrata on oppofite fides
of the fame valley, or the fame inlet of the fea ;
we fhall fee abundant reafon to conclude, that
the earth has been the theatre of many great

revolutions, and that nothing on its furface has |

been exempted from their effects.
To trace the feries: of thefe revolutions, to
explain their caufes, and thus to connect toge-
ther all the indications of change that are found
in the mineral kingdom, is the proper object of
a ‘THEORY OF THE. EARTH.
But, though the attention of men may be

turned to the theory of the earth by a very fu- —
perficial acquaintance with the phenomena of |

geology, the formation of fuch a theory requires

an accurate and extenfive examination of thofe |
phenomena, and is inconfiftent with any buta |
very advanced ftate of the phyfical fciences.

There is, perhaps, in thofe {ciences, no refearch
more arduous than this; none certainly where

the fubjed& is fo complex ; where the appearan- f

ces are fo extremely diverfified, or fo widely
{cattered, and where the caufes that have ope-
rated are fo remote from the {phere of ordinary

obfervation. Hence the attempts to form a`

theory of the earth are of very modern origin,
and as, from the fimplicity of its fubject, aftro-

nomy is the eldeft, fo, on account of the com- i
plexnefs

—

‘HUTTONIAN THEORY. 3

plexnefs of its fubject, geology is the youngeft
of the {ciences.

It is foreign from the prefent sts to en-
ter on any hiftory of the fyftems that, fince the
rife of this branch of fcience, have been invent-

, ed to explain the phenomena of the mineral
kingdom. It is fufficient to remark, that thefe

fyftems are ufually reduced to two claffes, ac-

| cording as they refer the origin of terreftrial bo-
| dies to FIRE or to WATER; and that, conform-
_ ably to this divifion, their followers have of late
been diftinguithed by the fanciful names of Vul-
į canifts and Neptunifts. To the former of thefe

Dr Hurron belongs much more than to the lat-

_ ter; though, as he employs the agency both of
fire and of water in his fyftem, he cannot, in
_ firict propriety, be arranged with either.

In the fucciné& account which I am’ nowa-

_ bout to give of this fyftem, I fhall confider the
_ mineral kingdom as divided into two parts,

namely, {tratified and unftratified fubftances. Al
fhall treat, firt, of the phenomena peculiar to
the ftratified ; next, of thofe peculiar to the un-
ftratified ; and, laftly, of the phenomena com-
mon to both. Beginning, then, with the firft,
the fubje&t naturally divides itfelf into three
branches ; viz. the materials, the confolidation,

and the po/fition of the ftrata.

A2 SECT-

4 ILLUSTRATIONS OF THE

SECTION 6

OF THE PHENOMENA PECULIAR TO STRATIFIED
BODIES. ;

1. Materials of the Strata.

1. WT is well known that, on removing the |

loofe earth which forms the immediate
furface of the land, we come to the folid rock,
of which a great proportion is found to be re-
gularly difpofed in ftrata, or beds of determi-
nate thicknefs, inclined at different angles to the —
horizon, but feparated from one another by |
equidiftant fuperficies, that often maintain their
parallelifm to a great extent. Thefe ftrata bear
fuch evident marks of being depofited by water,
that they are untverfally acknowledged to have |
had their origin at the bottom of the fea; and
it is alfo admitted, that the materials which they
confit of, were then either foft, or in fuch a
ftate of comminution and feparation, as render-
ed them capable of arrangement by the action
of the water in which they were immerfed.
Thus far moft of the theories of the earth agree; _
but

TFL

HUTTONIAN THEORY. 5

but from this point they begin to diverge, and
each to affume a character and direction pecu-
liar to itfelf. Dr Hutton’s does fo, by laying
down this fundamental propofition, That in all
the ftrata we difcover proofs of the materials
having exifted as elements of bodies, which muft
have been deftroyed before the formation of
thofe of which thefe materials now actually
make a part *.

2. The calcareous ftrata are the portion of
the mineral kingdom that gives the cleareft tef-
timony to the truth of this affertion. They of-
ten contain fhells, corals, and other exuvie of
marine animals in fo great abundance, that they

appear to be compofed of no other materials.

Though thefe remains of organized bodies are
now converted into ftone or into fpar, their

{hape and interior ftructure are often fo well
_ preferved, that the fpecies of animal or plant of
© which they once made a part, can ftill be diftin-

guifhed and pointed out among the living inha-
bitants of the ocean.

Others of the calcareous ftrata appear to be
compoled of fragments of fome ancient rocks,
which, after having been broken, have been
again united into a compact ftone. In thefe we
find pieces clearly marked as having been once
continuous, but now placed at a diftance from
, A3 one

* Hutton’s Theory, vol.i. p. 20. &c.

6 ILLUSTRATIONS OF THE

one another, and exhibiting exactly the fame

appearances as if they floated in a fluid of the
fame f{pecific gravity with themfelves.

From thefe, therefore, and a variety of fimi-
lar appearances, Dr Hutton concludes, that the
materials of all the calcareous ftrata have been
furnifhed, either from the diffolution of former
frata, or from the remains of organized bodies,
But, though this conclufion is meant to be ex-
tended to all the calcareous ftrata, it is not af-
ferted that every cubic inch of marble or of
limeftone contains in it the characters of its for-
mer condition, and of the changes through
which it has pafled. It may, however, be fafe-
ly affirmed, that there is fcarce any entire ftra-
tum where fuch characters are not to be found.
Thefe muft be held as decifive with refpect to
the whole fyftem of ftrata to which they belong ;

they prove the exiftence of calcareous rocks be- —

fore the formation of the prefent ; and, as the
deftru&tion of thofe is evidently adequate to the
fupply of the materials of thefe that we now
fee, to look for any other fupply were fuperflu-
ous, and could only embarrafs our reafonings by
the introduction of unneceflary hypothetes *.

3. The fame conclufions refult from an ex-
amination of the filiceous ftrata; under which
we may comprehend the common fand-ftone,

and
* NOTE I.

—

HUTTONIAN THEORY. x

and alfo thofe pudding-ftones or breccias where
the gravel confifts of quartz. In all thefe in-
ftances, it is plain, that the fand or gravel exift-
ed in a ftate quite loofe and unconnected, at the

bottom of the fea, previous to its confolidation
into ftone. But fuch bodies of gravel or fand

could only be formed from the attrition of large

= males of quartz, or from the diffolution of fuch
_ fand-ftone ftrata as exift at prefent; for it will

hardly be alleged, that fand is a cryftallization
of quartz, formed from that fubftance, when it
paffes from a fluid to a folid ftate.

Thofe pudding-ftones in which the gravel is

round and polifhed, carry the conclufion ftill

farther, as fuch gravel can only be formed in the
beds of rivers or on the fhores of the fea; for,

in the depths of the ocean, though currents are

known to exift, yet there can be no motion of
the water fufficiently rapid to produce the at-
trition required to give a round figure and

= {mooth furface to hard and irregular pieces of

ftone. There muft have exifted, therefore, not
only a fea, but continents, previoufly to the for-

mation of the prefent ftrata.
_ The fame thing is clearly fhewn by thofe pe-
- trifaGtions of wood, where, though the vegeta-

ble firu@ture is perfe&ly preferved, the whole
mais is filiceous, and has, perhaps, been found
A 4 | in

8 ILLUSTRATIONS OF THE

in the heart of fome mountain, deep imbedded
in the folid rock.

4. Chara@ers of the fame import are aie
_ found among the argillaceous ftrata, though per-
haps more rarely than among the calcareous or
filiceous. Such are the impreffions of the leaves
and {tems of vegetables ; alfo the bodies of fith
‘and amphibious animals, found very often in
the different kinds of argillaceous fchiftus, and
in moft inftances having the figure accurately
preferved, but the fubftance of the animal re-
placed by clay or pyrites. Thefe are all re-
mains of ancient feas or continents; the latter of
which have long fince fipo from the fur-
face of the earth, but have ftill their memory
preferved in thofe archives, where nature has
recorded the revolutions of the globe.

5. Among bituminous bodies, pit-coal is the
only one which conftitutes regular and extenfive
ftrata; and no foffil has its origin from the
wafte of former continents, marked by ttronger
and more diftin@ chara@ers. Not to mention
that the coal ftrata are alternated with thofe
that have been already enumerated, and that
they often contain fhells and ‘corals, perfe@ly
mineralized, it is fufficient to remark, that there
are entire beds of this foffil, which appear to
confift wholly of wood, and in which the fibrous
ftructure is perfectly preferved. From thefe in-

ftances,

Spa

7
—]

imbedgy

bre. alf,
ough Der

the leave
les of fif
often i
hiftus, ant
accurate)
animal r
are all n
he lattero

ym the fur

ir memo!
nature h

coal is thi

] extenfi

from th

Jy ftrong?
O mentil
vith tho
and th
perfeôl
that the
appe!"
tb e fibro
p thefe ;
franc

as we may call them;

HUTTONIAN THEORY. 9

fiances, the appearances of vegetable ftructure
may be traced through all poflible gradations,
down to an evanefcent ftate. This laft ftate is
undoubtedly the moft common; and though
coal does not then, on bare infpection, make
known its vegetable origin, yet, if we take it in
connection with the other terms of the feries, `
if we confider that the
two extremes, viz. coal, with the vegetable
ftructure perfe, and coal without any fuch
ftructure vifible, are often found in the fame or
in contiguous beds; and, if we remark, that
through all thefe gradations coal contains near-
ly the fame chemical elements, and yields, on

_analyfis, bitumen and charcoal, combined with

a greater or lefs proportion of earth: if we take
all thefe circumftances into account, we cannot
doubt that this foffil is every where the fame,
and derives its origin from the trees and plants
that grew on the furface of the earth before the
formation of the prefent land.

6. Dr Hutton has further obferved, that if
thofe ancient continents were at all fimilar to
the prefent, we can be at no lofs to account for
the want of any diftin& mark of vegetable or-
ganization in the greater part of the coal ftrata.
It is plain, that the daily wafte of animal and
vegetable fubftances on the furface of the earth,
muft difengage a great quantity of oily as well

as

I0 ILLUSTRATIONS OF THE

as carbonic matter, which, with whatever ‘ele-
ment it is at firt combined, is ultimately deli-
vered into the ocean. Thus, the oily or fuligi-
nous parts of animal and vegetable fubftances,
let loofe by burning, firft afcend into the atmo-
fphere, but are at length precipitated, and either
fall immediately into the fea, or are, in part at
leaft, wafhed down into it from the land. From
other caufes alfo, much vegetable matter is car-
ried down by the rivers; and the whole quan-
tity of animal and vegetable fubftances thus de-
livered into the fea, muft be very confiderable,
amounting annually to the whole refiduum of
thofe fubftances, not employed in the mainte-
nance or reproduction of animal and vegetable
bodies. Whether chemically united to the wa-
ters of the ocean, or fimply fufpended in them,
this matter is at laft precipitated, and, mingling
with earthy fubftances, is formed into ftrata, the
place of which will be determined by the cur-
rents, the pofition of the prefent continents, and
many other circumftances not eafily enumera-
ted. |

If, then, an order of things fimilar to what
we now fee, exifted before the formation of the
prefent ftrata, it would neceffarily happen, that

the animal and vegetable fubftances, diffufed —

through the ocean, being feparated from the
water, would be depofited at the bottom of the
fea,

a

——_

Dianai

HUTTONIAN THEORY. II

fea, and, in the courfe of ages, would form beds,
lefs or more pure, according to the quantity of
earth and other fubftances depofited at the fame
time. . Thefe beds being confolidated and mi-
neralized by operations that are afterwards to

_ be confidered, have been converted into pit-coal,

the parts of which are impalpable, and retain
nothing of their primitive ftructure *.

If, then, the formation of coal from animal
and vegetable bodies be admitted, the gene-
ral pofition which derives the origin of the
ftrata from the wafte of former land, as it is
applicable to all the kinds already enume-
rated, and of courfe to all thofe with which
they are alternated, comprehends a very large
‘portion of the earth’s furface. It comprehends,

indeed, all the ftrata ufually diftinguithed by

the name of Secondary; but there is another
great divifion of the mineral kingdom, viz. the
rocks, called Primitive, which, as they are ne-
ver alternated with the fecondary, but are al-
ways inferior to them, muft be further exami-
ned, before we can decide whether the fame con-
clufion extends to them or not.
_7- Here it muft be carefully obferved, that,
among the primary rocks, the granite is not
meant to be included, except where that ftone
is ftratified, and either coincides with veined
granite
* Nore it.

12 ILLUSTRATIONS OF THE

granite or with gneifs. The primitive ftrata, in
Dr Hutton’s theory, comprehend, befides gneifs,
the micaceous, chlorite, hornblend, and fili-
ceous {chiftus, together with flate, and fome
other kinds of argillite; to which we muĝ
add, ferpentine, micaceous limeftone, and the
greater part of marbles. Thefe are moftly
diftinguifhed by their laminated ftructure, by
having their planes much elevated with re-
{pect to the horizon, and by belonging more
to the mountainous than the level parts of the
earth’s furface. They rarely contain vefti-
ges of organized bodies ; fo rarely, indeed, that
they were called primitive by the geologifts who
firft diftinguifhed them from other rocks, on the
fuppofition of their being part of the prime-
val nucleus of the globe, which had never un-
dergone any change whatfoever; but this,
I believe, has now almoft ceafed to be the opi-
nion of any geologift*. The Neptunifts hold
the rocks, here enumerated, and alfo granite, to
be produced by aqueous depofition ; but main-
tain them to be in the ftricteft fenfe primeval,
and of a formation antecedent to all organized
bodies. :

8. In eppofition to this, Dr Hutton maintain-
ed, that the primary fchiftus, like all the other
ftrata, was formed of materials depofited at the

bottom

* NofE III.

haii

——

— 4

HUTTONIAN THEORY. 53

bottom of the fea, and collected from the wafte
of rocks ftill more ancient. When, therefore,
he conformed to the received language of mine-
ralogifts, by calling thefe ftrata primitive, he
only meant to defcribe them as more ancient
than any other ftrata now exifting, but not as
more ancient than any that ever had exifted.
They are diftinguifhed, in his fyftem, by the
name of Primary, rather than of Primitive ftra-
ta. vor

That the account now given of their origin
is well founded, may be proved by unqueftion-
able facts. For, firft, though, agreeably to the
obfervation juft made, the ancient ftrata do but
rarely contain any remains of organized bodies,
they are not entirely deftitute of them. Differ-
ent places in this ifland have been pointed out,
by Dr Hutton, where marine obje&ts have been
difcovered in primary limeftone, either by him-
felf or others, and it would not be difficult to
add more initances of the fame kind*. In
Dauphiny, coal, which is certainly a derivative
fubftance, has been found among mountains

which have a title to the character of primitive,

fuch as no one will difpute. Thefe facts put
the compofition of fuch rocks from loofe
materials, beyond all doubt, and alfo prove

_their formation to be pofterior to the exiftence

of

* NoTE Iv.

i4 ILLUSTRATIONS OF THE

of an animal and vegetable fyftem. They do |

indeed prove this in the ftricteft fenfe, only of
the particular beds in which they are found ;
but as thefe beds are in all other refpedts as
much to be accounted primary as any part of
the mineral kingdom, it is evident that the ne-
gative inftances are here of no force, and that
nothing can be gained to the adverfaries of this
opinion by denying it in general, if they are
obliged to admit it in a fingle cafe,

9. Again, itis certain, as Dr Hutton remarks,
that there are few confiderable bodies of fchittus,
even the mofl decidedly primitive, where fand
and gravel may not in fome parts be obferved.
Indeed, it is not only true that they are to be
found in fome parts of them ; but, in fact, among
“ many of the primitive mountains, we find large
‘tracts, compofed entirely of a fchiftofe and much
indurated fand-ftone, in beds highly inclined,
fometimes alone, fometimes alternated with
other fchifti. In many of them, the fand of
which they confift appears to be entirely of
granite, from the detritus of which rock it fhould
feem that they were chiefly formed.

ro. Thus we conclude, that the ftrata both
primary and fecondary, both thofe of ancient
and thofe of more recent origin, have had their
materials furnifhed from the ruins of former
continents, from the diffolution of rocks, or the

deftruction

hadi

aiai

HUTTONIAN THEORY. 15

deftruction of animal or vegetable bodies, fimi-
lar, at leat in fome refpedts, to thofe that now
occupy the furface of the earth. This conclu-
fion is not indeed proved of every individual
portion of rock, but it is demonftrated of many
and large parts, and thofe fcattered indifferently
through all the varieties of the ftrata; and
therefore, from the rules of the ftricteft reafon-
ing, we muft infer, that the whole is derived
from the fame origin *.

_ Thus far concerning the materials of the ftra-
ta; and, as thefe were originally loofe and un-
connected, we muft next confider by what means
they were confolidated into ftone.

2. Confolidation of the Strata.

11. Though Dr Hutton has no where defi-
ned the meaning of the term confolidation, he
has been fcrupuloufly exact in ufing it conftant-
ly in the fame fenfe. He underftands by it, not
merely that quality in a hard body by which its
parts cohere together, but as that ws which it

fills up the fpace catiptehe nded within its far-
face, being to fenfe withon BASEA and im-
pervious to air and moifture, :
Now

* NOTE ve

76 ILLUSTRATIONS OF THE

Now, a porous mafs of unconnected materials,
fuch as the ftrata appear originally to have been,
can acquire hardnefs and folidity only in two
ways, that is, either when it is firft reduced by
heat into a ftate of fufion, or at leaft of foftnefs,
and afterwards permitted to cool; or when matter
that is diffolved in fome fluid menftruum, is in-
troduced along with that menftruum into the
porous mafs, and, being depofited, forms a ce-
ment by which the whole is rendered firm and
compact. Fire and water, therefore, are the
only two phyfical agents to which we can afcribe
the confolidation of the ftrata ; and, in order to
determine to which of them that effec is to be
attributed, we muft inguire whether there are
any certain characters that diftinguifh the ac-
tion of the one from that of the other, and
which may be compared with the phenomena
actually obferved among mineral fubftances.

12. Firft, then, it is evident, that the con-
folidation produced by the action of water, or
of any other fluid menftruum, in the manner juft
referred to, muft neceffarily be imperfect, and
can never entirely banifh the porofity of the
mafs. For the bulk of the folvent, and of the
matter it contained in folution, being great-
er than the bulk of either taken fingly, when
the latter was depofited, the former would have
fufficient room left, and would continue to oc-

: cupy

HUTTONIAN THEORY. 17

cüpy a certain fpace in the interior of the ftra-
ta. A liquid folvent therefore could never
fhut up the pores of a body to the entire exclu-
fion of itfelf; and, had mineral fubftances been
confolidated, as here fuppofed, the folvent ought
either to remain within them in a liquid ftate,
or, if evaporated, fhould have left the pores
empty, and the body pervious to water. Nei-
ther of theie, however, is the fact; many ftra-
tified bodies are perfectly impervious to water,
and few mineral fubftances contain water in
a liquid ftate. That they fometimes contain
it, chemically united to them, is no proof of
their folidity having been brought about by
that fluid; for fuch chemical union is as con-
fiftent with the fuppofition of igneous as of
aqueous confolidation, fince the region in which
the fire was applied, on every hypothefis, muft
have abounded with humidity.

13. Again, if water was the folvent by which

the confolidating matter was introduced into the

interftices of the ftrata, that matter céuld confitt
only of fuch fubftances as are foluble in water,
whereas it confifts of a vait variety of fubftances,
altogether infoluble either in it, or in any fingle
menftruum whatfoever. The ftrata are confo-
lidated, for example, by quartz, by fluor, by

feltfpar, and by all the metals, in their endlefs

combinations

18 ILLUSTRATIONS OF THE

tions with fulphureous bodies. To af.
firm that water was ever capable of diffolving
thefe fubftances, is to afcribe to it powers which
it confefledly has not at prefent ; and, therefore,
it is to introduce an hypothefis, not merely gra-
tuitous, but one which, phyfically fpeaking, is
abfurd and impoffible.

This is not all, however; for, éven if this
difficulty were to be paffed over, it would fill
be required to explain, how the water, which,
together with the matter which it held in folu-
tion, had infinuated itfelf into the pores of the
ftrata, became fuddenly difpofed to depofite that
matter, and to allow it, by cryftallization or
concretion, to affume a folid form*, The Nep-
tunifts muft either affign a fufficient reafon for
this great and univerfal change, or muft expect
to fee their fyftem treated as an inartificial ac-
cumulation of hypothefes which afligns oppofite
virtues to the fame fubjed, and is alike at va-
riance with nature and with itfelf; in a word,
afyftem that might pafs for the invention of
an age, when as yet found philofophy had not
alighted on the earth, nor taught man that
he is but the minifter and interpreter of nature,
and can neither extend his power nor his know-

ledge

* Note VI.

HUTTONIAN THEORY. 19

ledge a hair’s-breadth beyond his experience and
obfervation of the prefent order of things *.

14. Such are the more obvious, but I think
unan{werable objections, that may be urged
againft the aqueous confolidation of the ftra-
ta. It is true, that ftony concretions, fome of
them much indurated, are formed in the humid
Way under our eyes. Very particular condi-
tions, however, are required for that purpofe,
and conditions fuch as can hardly have exifted
at the bottom of the fea. Firft, The water muf
diffolve the fubftance of which the concretion
is to be formed, as it actually does in the cafe
of calcareous, and in certain circumftances, in
that of filiceous, earth. Secondly, It muft be
feparated from that fubftance, as by evaporation,
or by a combination of the matter diffolved
with fome third fubftance, to which it has a
greater aflinity than to water, fo as to form with
it an infoluble compound. Laftly, The water
that is deprived of its folution muft be carried

off, and more of that which contains the folu-
' tion muft be fupplied, as fometimes happens

B2 He where

* Homo nature minifter, et interpres tantum facit
et intelligit, quantùm de naturæ ordine re, vel mente,
obfervaverit: nec amplius fcit, aut poteft.

` Nov. Org. lib. i. aph. x.

20 ILLUSTRATIONS OF THE

where water runs in a ftream, or drops from
the roof of a cavern. The two laft condi.
tions are peculiarly inapplicable to the bottom
of the fea, where the ftate of the furrounding
fluid would neither permit the water that was
deprived of its folution from being drawn off,
nor that which contained the folution from fue-
ceeding it.

It is further to be obferved, that the HEEN
dation of ftalactitical concretions, that is, the fill-
ing up of their pores, is always imperfect, and is
brought about by the repeated action of the fluid
running through the porous mafs, and continu-
ing to depofite there fome of the matter it holds
in folution. This, which is properly infiltra-
tion, is incompatible with the nature of a fuid,
either nearly, or altogether quiefcent.

15. In order to judge whether objections of
equal weight can be oppofed to the hypothefis
of igneous confolidation, we muft attend toa
very important remark, firft made by Dr Hut-
ton, and applied with wonderful fuccels to ex-
plain the moft myfterious phenomena of the
mineral kingdom.

It is certain, that the effeéts of fire on bo-
dies vary with the circumftances under which
it is applied to them, and therefore a confider-
able allowance muft be made, if we would com-

pare

HUTTONIAN THEORY. 2I

paré the operation of that element when it con-
folidated the ftrata, with the refults of our daily
experience. The materials of the ftrata were
difpofed, as we have already feen, loofe and
unconnected, at the bottom of the fea; that
is, even on the moft moderate «ftimation, at the
depth of feveral miles under its furface. At
this depth, and under the preffure of a column
of water of fo great a height, the action of heat
would differ much from that which we obferve
here upon the furface; and, though our expe-
rience does not enable us to compute with ac-
curacy the amount of this difference, it never-
thelefs points out the direction in which it muft
lie, and even marks certain limits to which it
would probably extend.

The tendency of an increafed preffure on

the bodies to which heat is applied, is to re-

ftrain the volatility of thofe parts which o-
therwife would make their efcape, and to
force them to endure a more intenfe ation of
heat. At a certain depth under the furface
of the fea, the power even of a very in-
tenfe heat might therefore be unable to drive
off the oily or bituminous parts from the inflam-
mable matter there depofited, fo that, when the
heat was withdrawn, thefe principles might be
found ftill united to the earthy and carbonic
parts, forming a fubftance very unlike the re-

B 3 fiduum

22 ILLUSTRATIONS OF THE

fiduum obtained after combuftion under a pref-
fure no greater than the weight of the atmo-
fphere. It is in like manner reafonable to be-
lieve, that, on the application of heat to calca-
reous bodies under great comprefiion, the car-
bonic gas would be forced to remain; the ge-
neration of quicklime would be prevented, and
the whole might be foftened, or even complete-
ly melted; which laft effect, though not di-
rectly deducible from any experiment yet made,
is rendered very probable, from the analogy of
certain chemical phenomena.

16. An analogy of this kind, derived from a
property of the barytic earth, was fuggefted by
that excellent chemift and philofopher, the late
Dr Brack. The barytic earth, as is well known,
has a ftronger attraction for fixed air than com-
-~ mon calcareous earth has, fo that the carbonate
of barytes is able to endure a great degree of
heat before its fixed air is expelled. Accord-
ingly, when expofed to an increafing heat, at a
certain temperature, it is brought into fufion,
the fixed air ftill remaining united to it: if the
heat be further increafed, the air is driven off,
the earth lofes its fluidity, and appears in a
cauftic ftate. Here, it is plain, that the barytic
earth, which is infufible, or very refractory, per
fe, as well as the calcareous, owes its fufibility
to the prefence of the fixed air; and it is there-

fore

HUTTONIAN THEORY. 23

fore probable, that the fame thing would hap-
pen to the calcareous earth, if by any means the
fixed air were prevented from efcaping when
great heat is applied to it. This efcape of the
fixed air is exactly what the compreflion in

~ the fubterraneous regions is calculated to pre-

vent, and therefore we are not to wonder if,
among the calcareous ftrata, we find marks of
actual fufion having taken place *,

17. Thefe effects of preffure to refift the fle.
compofition, and augment the fufibility of bodies,
being once fuppofed, we fhall find little difficulty
in conceiving the confolidation of the ftrata by
heat, fince the intervals between the loofe mate-
tials of which they originally confifted may have
been clofed, either by the foftening of thofe mate-
rials, or by the introduction of foreign matter a-
mong them, in the ftate of a fluid, or of an elaftic
vapour. No objection to this hypothefis can arife
from the confiderations {tated in the preceding
cafe; the folvent here employed would want no
pores to lodge in after its work was completed,
nor would it find any difficulty in making its re-
treat through the denfeft and moft folid fubftan-
ces in the mineral kingdom, Neither can its
incapacity to. diflolve the bodies fubmitted to its
action be alleged. Heat is the moft powerful
and moft general of all folvents; and, though

B4 fome

* Note VII.

24 ILLUSTRATIONS OF THE

fome bodies, fuch as the calcareous, are able
to refift its force on the furface of the earth,
yet, as has jut been fhewn, it is perfectly a.
greeable to analogy to fuppofe, that, under
great preflure, the carbonic ftate of the lime
being preferved, the puret limeftone or mar-.
ble might be foftened, or even melted. With
refpe& to other fubftances, lefs doubt of their
fulibility is entertained ; and though, in our
experiments, the refraGtory nature of filice-
ous earth has not been completely fubdued, a
degree of foftnefs and an incipient fufion have
neverthelefs been induced.

Thus it appears, in general, that the fame dif-
ficulties do not prefs againft the two theories
of aqueous and of igneous confolidation ; and,
that the latter employs an agent incomparably
more powerful than the former, of more gene-
ral activity, and, what is of infinite importance
in a philofophical theory, vaftly more definite
in the laws of its operation.

18. A more particular examination of the
different kinds of foffils will confirm this con-
clufion, and will fhow, that, wherever they bear
marks of having been fluid, thefe marks are fuch
as characterize the fluidity of fufion, and diftin-
guifh it from that which is produced by folu-
tion ina menftruum. Dr Hutton has enume-
rated many of thefe difcovered in the courfe of

: that

HUTTONIAN THEORY. 25

that careful and accurate ination of foffils,
in which he probably never was excelled by
any mineralogift. It will be fufficient here to
point out a few of the moft remarkable exam-
ples. :

19. Foffil-wood, penetrated by filiceous mat-
ter, is a fubftance well known to mineralogifts :
it is found in great abundance in various fitua-
tions, and frequently in the heart of great bodies
of rock. On examination, the filiceous matter is
often obferved to have penetrated the wood very
unequally, fo that the vegetable firucture re-
mains in fome places entire; and in other places is
loft in a homogeneous mafs of agate or jafper.
Where this happens, it may be remarked, that
the line which feparates thefe two parts is quite
fharp and diftin@, altogether different from
what muft have taken place, had the flinty mat-
ter been introduced into the body of the wood,

by any fluid in which it was diffolved, as it

would then have pervaded the whole, if not
uniformly, yet with a regular gradation. In
thole fpecimens of foffil-wood that are partly
penetrated by agate, and partly not penetrated
at all, the fame fharpnefs of termination may
be remarked, and is an appearance highly cha-

_ racteriftic of the fluidity produced by fufion.

20. The round nodules of flint that are
found in chalk, quite infulated and feparate
from

26 ILLUSTRATIONS OF THE

from one another, afford an argument of the
Tame kind ; fince the flinty matter, if it had been
carried ae the chalk by any folvent, muft have
been depofited with a certain degree of unifor-
_ mity, and would not now appear colleéted into
feparate mafles, without any trace of its exift-
ence in the intermediate parts. On the other
hand, if we conceive the melted flint to have
been forcibly injected among the chalk, and to
have penetrated it, fomewhat as mercury may,
by preflure, be made to penetrate through the
pores of wood, it might, on cooling, exhibit the
fame appearances that the chalk-beds of Eng-
land do actually prefent us with.

The filiceous pudding-ftone is an inftance
clofely connected with the two laft; in it we
find both the pebbles, and the cement which
unites them, confifting of flint equally hard and
confolidated ; and this circumftance, for which
it is impoffible to account by infiltration, or the
infinuation of an aqueous folvent, is perfedtly
confiftent with the fuppofition, that a ftream of
melted flint has been forcibly injeted among a
mafs of loofe gravel.

21. The common grit, or fandftone, though
it certainly gives no indication of having pof-
feffed fluidity, is ftrongly expreffive of the ef-
fects of heat. It is fo, efpecially in thofe in- —
fiances where the particles of quartzy fand, of

| 2 which

HUTTONIAN THEORY. 27

i which it is compofed, are firmly and clofely
united, without the help of any cementing fub-
_ ftance whatfoever. This appearance, which is
very common, feems to be quite inconfiftent

with every idea of confolidation, except an in-

' cipient fufion, which, with the afliftance of a

fuitable compreffion, has enabled the particles
of quartz to unite into ftone.

It has indeed been afferted, that the mere ap-
pofition of ftony particles, fo as to permit their

~ corpufcular attrafion to take place, was fufli-

cient to form them into ftone. To this Dr Hut-

' ton has very well replied, that, admitting the

poflibility of a hard and firm body being pro-
duced in this way, of which, however, we have
no proof, the clofe and compa& texture, the
perfe& confolidation of the ftones we are now
{peaking of, would ftill remain to be explained,
and of this it is evident that the mere appo-

' fition of particles, and the force of their mu-

tual attraction, can afford no folution.

22. Thefe proofs that the ftrata muft have en-
dured the action of intenfe heat, though imme-
diately deduced from thofe of the filiceous ge-
nus only, extend in reality to all the ftrata, of
every kind, with which they are found alter-
nated. It is impoflible that heat, of the inten-

_ fity here -fuppofed, can have acted on a particu-

lar

28 ILLUSTRATIONS OF THE

lar ftratum, and not on thofe that are contigu-
ous to it; and, as there are no {trata of any kind
with which the quartzy and filiceous are not
intermixed, fo there are none of which the ig.
neous confolidation is not thus rendered proba-
ble. We need reft nothing, however, on this
argument, as the foflils of every genus may be
fhewn to {peak diftin@ly for themfelves.

23. Thofe of the calcareous genus do fó
perhaps more fparingly than the reft; yet
even among them there are many facts, that,
though taken unconnected with all others, are
fufficient to eftablifh the action of fubterraneous
fire. Such, for example, are the calcareous
breccias, compofed of fragments of marble or
limeftone, and not only adapted to each other’s
fhape, but indented into one another, in a man-
ner not a little refembling the futures of the hu-
man cranium. From fuch inftances, it is im-
pofflible not to infer the foftnefs of the calcareous
fragments when they were confolidated into
one mals. Now, this foftnefs could be induced
only by heat; for it muft be acknowledged,
that the action of any other folvent is quite in-
adequate to the foftening of large fragments of
ftone, without diflolving them altogether.

24. In many other inftances it appears cer-
tain, that the {tones of the calcareous genus
have been reduced by heat into a ftate of flui-

dit¥

HUTTONIAN THEORY. 29

in dity much more perfect. Thus, the faline or
* finer kinds of marble, and many others that
have a ftru@ure highly cryftallized, muft have

been foftened to a degree little fhort of fufion,

before this cryftallization could take place.
_ Even the petrifaGiions which abound fo much

in limeftones, tend to eftablith the fame fact ;
for they poffefs a fparry ftructure, and muft have
acquired that ftructure in their tranfition from
a fluid to a folid ftate *.

25. In accounting, by the operation of heat,

for thefe appearances of fluidity, Dr Hutton has

proceeded on the principle already laid down,
as conformable to analogy, that calcareous earth,
under great compreflion, may have its fixed air

retained in it, notwithftanding the action of in-

tenfe heat, and may, by that means, be reduced
into fufion, or into a ftate approaching to it.
In all this, I do not think that he has departed
from the ftricteft rules of philofophical invefti-
gation. The facts juft ftated prove, that lime-

- ftone was once foft, its fragments retaining at

the fame time their peculiar form, an effect to
which we know of none fimilar but thofe of
fire; and therefore, though we could not con-
jecture how heat might be applied to limeftone
fo as to melt it, inftead of reducing it to a calx,
we fhould, neverthelefs, have been forced to

fuppofe

* Note VIIL

30 ILLUSTRATIONS OF THE

fuppofe, that this had a&tually taken place in
the bowels of the earth; and was a fact which,
though we were not able to explain it, we were
not entitled to deny. The principle juft men.
tioned relieves us therefore from a difficulty,
that would have embarraffed, but could not have
overturned, this theory of the earth.

26. From the arguments which the argilla.
ceous ftrata afford for the igneous confolidation
of foffils, I fhall fele& one on which Dr Hutton
ufed to lay confiderable ftrefs, and which fome
of the adverfaries of his fyftem have endeavour-
ed to refute. This argument is founded on the
ftructure of certain iron-ftones called /eptaria,
often met with among the argillaceous {chiftus,
particularly in the vicinity of coal. Thefe ftones
are ufually of a lenticular or fpheroidal form,
and are divided in their interior into diftiné
Jepta, by veins of calcareous fpar, of which one
fet are circular and concentric, the other ređi-
lineal; diverging from the centre of the for-
mer, and diminifhing in fize as they recede from
it. Now, what is chiefly to be remarked is, that
thefe veins terminate before they reach the furface
of the ftone ; fo that the matter with which they
are filled cannot have been introduced from with-
out by infiltration, or in any other way what-
foever. The only other fuppofition, therefore,

that is left for explaining the fingular ftructure
of

HUTTONIAN THEORY. 3t

Of this foffil, is, that the whole mafs was origin-

ally fluid, and that, in cooling, the calcareous

part feparated from the reft, and afterwards
éryftallized. .
27. It has been urged againft this theory of

the feptaria, that thefe ftones are fometimes

found with the calcareous veins extending all
the way to the circumference, and of courfe
communicating with the outfide. But it muft
be obferved, that this fa& does not affe& the
argument drawn from {pecimens in which no
fuch communication takes place. It is at beft
only an ambiguous inftance, that may be ex-
plained by two oppofite theories, and may be
reconciled either to the notion of igneous or of
aqueous confolidation: but if there is a fingle
clofe feptarium in nature, it can, of courfe, be

ij) explained only by one of thefe theories, and the

other muft, of néceflity, be rejected. Befides,
it is plain, that a clofe feptarium can never have
been open, though an open feptarium may very
well have been clofe; and indeed, as this ftone
is, in certain circumftances, fubject to perpetual
exfoliation, it would be wonderful if no one was
ever found with the calcareous veins reaching
to the furface, With regard to the light, there-
fore, that they give into their own hiftory, thefe
two kinds of feptaria are by no means on an
equal footing; and this may ferve to fhew, how

neceflary

32 ILLUSTRATIONS OF THE

neceflary it is, in all induGive reafoning, and
particularly in a fubject fo complex as geology,
to feparate with care fuch phenomena as admit
of two folutions, from fuch as admit only of
one.

28. The bituminous ftrata come next to be
confidered ; and they are of great confequence
in the prefent argument, becaufe their diffimi-
larity in fo many particulars to all other mine-
ral fubftances, renders them what Lord Bacoy
calls an infantia fingularis, having the firft rank
among facts fubfervient to inductive inveftiga-
tion. But though unlike in fubftance to other
foffils, and compofed, as has been fhewn, of ma-
terials that belonged not originally.to the mine-
ral kingdom, they agree in many material cir-
cumftances with the ftrata already enumerated.
Their beds are difpofed in the fame manner,
and are alternated indifcriminately with thofe
of all the fecondary rocks, and, being formed
in the fame region, muft have been fubjeét to
the fame accidents, and have endured the ope-
ration of the fame caufes. They are traverfed
too like the other ftrata, by veins of all the me-
tals, of fpar, of bafaltes, and of other fubftances ;
and, whatever argument may hereafter be de-
rived from this to prove the action of fire on
the ftrata fo traverfed, is as much applicable
to coal as to any other mineral. The coal ftra-

ta

`
9 Ay
ig |

Olo '

mI
adni
aly ,

to }

Mimi

Mne
ACO

] 193
othe
f m
min
l cir
ratei
nne
thol
rme
act

HUTTONIAN THEORY. 33

ta alfo contain pyrites in great abundance, a
fubftance that is perhaps, more than any other,

` the decided progeny of fire. This compound
| of metal and fulphur, which is found in mineral

bodies of every kind, I believe, without any ex-

ception, is deftroyed by the contact of moifture,
Ueng `

and refolved into a vitriolic falt. At the fame
time it is found in the ftrata, not traverfing
them in veins, which may be fuppofed of more
recent formation than the ftrata themfelves ;

Bie but exifting in the heart of the moft folid rocks,

often nicely cryftallized, and completely inclo-
fed, on all fides, without the moft minute va-
cuity. The pyrites muft have been prefent,
therefore, when the ftrata were confolidated, and
it is inconceivable, if their confolidation was
brought about in the wet way, that a fubftance
fhould be fo generally found in them, the very
exiftence of which is incompatible with humi-
dity. This argument for the igneous origin of
the ftrata is applicable to them all, but efpe-
cially to thofe of coal, as abounding with pyri-

, tes more than any other.

29. The difficulty that here naturally prefents

cg _itfelf, viz. how vegetable matter, {uch as coal is

fuppofed to have been, could be expofed to the
action of intenfe heat, without being deprived

| of its inflammable part, is obviated by the prin-

ciple formerly explained concerning the effects
C of

34 ILLUSTRATIONS OF THE

of compreflion. The weight incumbent on the
{trata of coal, when they were expofed to the
intenfe heat of the mineral regions, may have
been fuch as to retain the oily and bituminous,
as well as fulphureous parts, though the whole
was reduced almoft to fufion; and thus, on cool.
ing, the fulphur uniting with iron might cryftal-

lize, and aflume the form of pyrites. '

30.’ The comprefiion, however, has not in every
inftance preferved the bituminous, in union with
the carbonic part of coal; and hence a mark
of the operation of fire quite peculiar to this fof-
fil, and found in thofe infufible kinds of it which
contain no bitumen, and burn without flame,
Thefe refemble, fome of them very precifely, and
all of them in a great degree, the products obtain-
ed by the diftillation of the common bituminous
coal; that is, they confit of charcoal, united
to an earthy bafis in different proportions. It
is natural therefore to conclude, that this fub-
ftance was prepared in the mineral regions by

the action of heat, which, in fome inftances, has.

driven off the inflammable part of the coal. That
the heat fhould,in fome cafes, have done fo, is
not inconfiftent with the general effe& attri-
buted to compreflion. ‘The conditions neceflary
for retaining the more volatile parts, may not
have been preient every where in the fame de-

é gree

2 HUTTONIAN THEORY. 95
le 3
~ gree, fo that the latter, though they could not
œ efcape, may have been forced from one part of

NT Te >

t

a ftratum, or body of ftrata, to another.

3T. In confirmation of this it muft be obferved,
that, as the fixed part of coal is thus found in
the bowels of the earth, feparate from the vola-
tile or bituminous, fo, in the neighbourhood of
coal ftrata, the latter is fometimes found with-

_ out any mixture of the former. The fountains

of naphtha and petroleum are well known; and
Dr Hutton has defcribed a ftratum of limeftone,
lying in the centre of a coal country, which
is pervaded and tinged by bituminous matter,
through its whole mafs, and has, at the fame
time, many clofe cavities in the heart of it, lined
with calcareous fpar, and containing foffil pitch,
fometimes in large pieces, fometimes in hemi-
{pherical drops, feattered over the furface of the
cavities. This combination could only be ef-
fected by a part of the inflammable matter of
the beds of coal underneath, being driven off
by heat, and made to penetrate the limeftone,
while it was yet foft and pervious to heated va-
pours *,

32. Hitherto we have enumerated thofe fof-
fils that are ‘either not at all, or very {paringly
foluble in water. There are, however, faline

C2 bodies

* Note rx:

36 ILLUSTRATIONS OF THE |

bodies among the mineral ftrata, fuch for. in.
ftance as rock-falt, which are readily diffolved
in water; and it yet remains to examine by
what caufe their confolidation has been effec
ed.

Here the theorifts who confider water as the
fole agent in the mineralization of fofiils, are in-
deed delivered from one difficulty, but it is on-
ly that they may be harder preffed on by ano-
ther. It cannot now be faid, that the men-
ftruum which they employ is incapable of dif-
folving the fubftances expofed to its action, as
in the cafe of metallic or ftony bodies; but it
may very well be afked, how the water came
to depofite the falts which it held in folution,
and to depofite them fo copioufly as it has done
in many places, without any veftige of fimi-
lar depofition in the places immediately conti-
guous. If they refufe to call to their affiftance
any other than their favourite element, they
will not find it eafy to anfwer this queftion,
and muft feel the embarraffment of a fyftem,
fubje@ to two difficulties, fo nicely, but f
unhappily adjufted, that one of them 1s al-
ways prepared to act whenever the other is re-
moved. If, on the other hand, they will ad-
mit the operation of fubterraneous heat, it ap-

pears poffible, that the local application of fuch
heat

{
$
i

HUTTONIAN THEORY. 37

heat may have driven the water, in vapour, from
one place to another, and by fuch action often
repeated in the fame fpot, may have produced
thofe great accumulations of faline matter, that
are actually found in the bowels of the earth.

33. But granting that, either in the way juft
pointed out, or in fome other that is unknown,
the falt and the water have been feparated, fome
further action of heat feems requifite, before a
compact, and highly indurated body, like rock-
falt, could be produced. ‘The mere precipita-
tion of the falt, would, as Dr Hutton has ob-
ferved, form only an affemblage of loofe cryftals
at the bottom of the fea, without folidity or co-
hefion: and to convert fuch a mafs into a firm
and folid rock, would require the application of
fuch heat as was able to reduce it into fufion.
The confolidation of rock-falt, therefore, how-
ever its feparation from the water is accounted
for, cannot be explained but on the hypothefis
of fubterraneous heat.

34. Some other phenomena that have been
obferved in falt mines, come in fupport of the
fame conclufion. The falt rock of Chefhire,
which lies in thick beds, interpofed between
{trata of an argillaceous or marly ftone, and is
itfelf mixed with a confiderable portion of the
fame earth, exhibits a very great peculiarity in
its ftrudture. Though it forms a mafs extreme-

C 3 ly

38 ILLUSTRATIONS OF THE

ly compact, the falt is found to be arranged in
round maffes of five or fix feet in diameter, not
truly fpherical, but each comprefied by thofe that
_furround it, fo as to have the fhape of an irre-
gular polyhedron. Thefe are formed of con.
centric coats, diftinguifhable from one another
by their colour, that is, probably by the greater
or lefs quantity of earth which they contain,
fo that the roof of the mine, as it exhibits a ho-
rizontal feétion of them, is divided into po.
lygonal figures, each with a multitude of poly-
gons within it, having altogether no inconfider-
able refemblance to a mofaic pavement. In the tri-
angular {paces without the polygons, the falt is
in coats parallel to the fides of the polygons.
The circumftances which gave rife to this
fingular ftru€ture we fhould in vain endeavour
to define; yet fome general conclufions con-
cerning them feem to be within our reach. It
is clear that the whole mafs of falt was fluid at
once, and that the forces, whatever they were,
which gave folidity to it, and produced the new
arrangement of its particles, were all in action
at the fame time. The uniformity of the coat-
ed ftructure is a proof of this, and, above all, the

comprefiion of the polyhedra, which is always
mutual, the flat fide of one being turned to the
flat fide of another, and never an 2 angle to an an-
gle, nor an angle to a fide, The coats formed as it

were

HUTTONIAN THEORY. 39

were round fo many different centres of attraction,
is alfo an appearance quite inconfiftent with the
notion of depofition; both thefe, however, are
compatible with the notion of folidity acquired by
the refrigeration of a fluid, where the whole mafs
is acted on at the fame time, and where no fol-
vent remains to be difpofed of after the indura-
tion of the reft.

35. Another fpecies of foffil-falt exhibits ap- «=
pearances equally favourable to the theory of
igneous confolidation. ‘This is the trona of A-
frica, which is no other than foda, or mineral al-
kali, in a particular ftate. The {pecimen of this
foffil in Dr Black’s, now Dr Hope’s, collection,
is of a fparry and radiated ftructure, and is evi-
dently part of the contents of a vein, having a
ftony cruft adhering to it, on one fide, with its
own {parry ftructure complete, on the oppofite.
It contains but about one-fixth of the water of
eryftallization effential to this falt when obtain- |
ed inthe humid way; and, what is particularly
to be remarked, it does not lofe this water, nor
become covered with a powder, like the com-
mon alkali, by fimple expofure to the air. It is
evident, therefore, that this foffil does not origi-

nate from mere precipitation; and when we

add, that in its {parry ftruture it contains evi-
dent marks of having once been fluid, we have
C4 little

4o ILLUSTRATIONS OF THE

little reafon to entertain much doubt concern.
ing the principle of its confolidation.

Thus, then, the teftimony given to the opera.
tion of fire, or heat, as the confolidating power
of the mineral kingdom, is not confined to a few
foffils, but is general over all the ftrata. How
far the unftratified foffils agree in fupporting the
fame conclufion, will be afterwards examined,

3. Pofition of the Strata *®,

30. We have feen of what materials the
{trata are compofed, and by what power they
have been confolidated; we are next to in-
quire, from what caufe it proceeds, that they
are now fo far removed from the region which
they originally occupied, and wherefore, from
being all covered by the ocean, they are at

prefent raifed in many places fifteen thoufand

feet above its furface. Whether this great
change of relative place can be beft accounted
for by the depreffion of the fea, or the elevation
of the ftrata themfelves, remains to be confider-
ed.

Of

* Theory of the Earth, vol. i. p. 120.

HUTTONIAN THEORY. 41

Of thefe two fuppofitions, the former, at firt
fight, feems undoubtedly the moft probable, and
we feel lefs reluctance to fuppofe, that a fluid,
fo unftable as the ocean, has undergone the great
revolution here referred to, than that the folid
foundations of the land have moved a fingle fa-
thom from their place. This, however is a

mere illufion. Such a depreffion of the level of

the fea as is here fuppofed, could not happen
without a change proportionally great in the fo-
lid part of the globe; and, though admitted as
true, will be found very inadequate to explain
the prefent condition of the ftrata.

37. Suppofing the appearances which clear-
ly indicate fubmerfion under water to reach
no higher than ten thoufand feet above the pre-
fent level of the fea, and of courfe the furface
of the fea to have been formerly higher by that
quantity than it is now; it neceflarily follows,
that a bulk of water has difappeared, equal to
more than a feven-hundredth part of the whole
magnitude of the globe*. The exiftence of
empty caverns, of extent fufficient to contain this
vaft body of water, and of fuch a convulfion as
to lay them open, and give room to the retreat
of the fea, are fuppofitions which a philofopher
could only be juftified in admitting, if they pro-
mifed to furnifh a very complete explanation of

7 appearances,

* Note X.

42 ILLUSTRATIONS OF THE

appearances. But this juftification is entirely
wanting in the prefent cafe; for the retreat of
the ocean to a lower level, furnifhes a very par.
tial and imperfect explanation of the phenome.
na of geology. It will not explain the num.
berlefs remains of ancient continents that are

involved, as we have feen, in the prefent, unlefs -

it be fuppofed that the ancient ocean, though it
rofe to fo great a height, had neverthelefs its
fhores, and was the boundary of land ftill high-
er than itfelf. And, as to that which is now more
immediately the object of inquiry, the pofition
of the ftrata, though the above hypothefis would
account in fome fort for the change of their
place, relatively to the level of the fea ; yet, if it
fhall be proved, that the flrata have changed
their place relatively to each other, and rela-
tively to the plane of the horizon, fo as to have
had an angular motion impreffed on them, it is
evident that, for thefe facts, the retreat of the
fea does not afford even the fhadow of a theo-
ry.

38. Now, it is certain, that many of the ftra-
ta have been moved angularly, becaule that,
in their original pofition they muft have been all
nearly horizontal. Loofe materials, fuch as fand
and gravel fubfiding at the bottom of the fea,
and having their interftices filled with water,
poffefs a kind of fluidity: they are difpofed to

yield

HUTTONIAN THEORY. 43

ti yield on the fide oppofite to that where the
ar preflure is greateft, and are therefore, in fome
degree, fubject to the laws of hydroftatics. On

ne, ; :
me this account they will arrange themfelves in ho-
ah rizontal layers ; and the vibrations of the incum-

ed bent fluid, by imprefling a flight motion back-
ward, and forward, on the materials of thefe lay-

+

a ers, will very much aflift the accuracy of their
1 level. |

k It is not, however, meant to deny, that the form
~ ofthe bottom might influence, in a certain de-
i gree, the ftratification of the fubftances depofited
i onit. The figure of the lower beds depofited on
H an uneven furface, would neceffarily be affected

by two caufes ; the inclination of that furface, on
@ the one hand, and the tendency to horizontality,

a on theother; but, as the formercaufe would grow
i lefs powerful as the diftance from the bottom
i increafed, the latter caufe would finally prevail,
it fo that the upper beds would approach to hori-
+ zontality, and the lower would neither be ex-
= adtly parallel to them, nor to one another.
u Whenever, therefore, we meet with rocks, dif-
f pofed in layers quite parallel to one another,
| we may ret affured, that the inequalities of the
i bottom have had no effect, and that no caufe
, hasinterrupted the ftatical tendency above ex-
i plained,

Now,

A4 ILLUSTRATIONS OF THE

Now, rocks having their layers exa@ly paral.
lel, are very common, and prove their original
horizontality to have been more precife than
we could venture to conclude from analogy
alone. In beds of fand-ftone, for inftance, no.
thing is more frequent than to fee the thin
layers of fand, feparated from one another by
layers ftill finer of coaly, or micaceous matter,
that are almoft exactly parallel, and conti-
nue fo to a great extent without any fenfible
deviation. Thefe planes can have acquired
their parallelifm only in confequence of the
property of water juft ftated, by which it ren-
ders the furfaces of the layers, which it de
polites, parallel to its own furface, and therefore
parallel to one another. Though fuch ftrata, `
therefore, may not now be horizontal, they mutt
have been fo originally ; otherwife it is impofii-
ble to difcover any caufe for their parallelifm,
or any rule by which it can have been produ-
ced. i

39. This argument for the original horizon-
tality of the ftrata, is applicable to thofe that are
now fartheft removed from that pofition. A-
mong fuch, for inftance, that are highly m-
clined, or even quite vertical, and among thofe
that are bent and incurvated in the moft fan-
taftical manner, as happens more efpecially in

the

HUTTONIAN THEORY. 45

the primary {chifti, we obferve, through all
their finuofities and inflections, an equality of
thicknefs and of diftance among their com-
ponent lamine. This equality could only be
produced by thofe lamine having been ori-
ginally fpread out on a flat and level furface,
from which fituation, therefore, they muft af-
terwards have been lifted up by the action of
fome powerful caufe, and muft have fuffered
this difturbance while they were yet in a cer-
tain degree flexible and ductile. Though the
primary direction of the force which thus ele-
vated them muft have been from below up-
wards, yet it has been fo combined with the

gravity and refiftance of the mafs to which it

was applied, as to create a lateral and oblique
thruft, and to produce thofe contortions of the
ftrata, which, when on the great fcale, are
among the moft ftriking and infiructive pheno-
mena of geology.

40. Great additional force is given to this ar-
sument, in many cafes, by the nature of the ma-
terials of which the ftratified rocks are compo-
fed. ‘The beds of breccia and pudding-ftone,
for inftance, are often in planes almoft vertical,
and at the fame time contain gravel-ftones, and
other fragments of rock, of fuch a fize and
weight, that they could not remain in their pre-

fent

46 ILLUSTRATIONS OF THE

fent pofition an inftant, if the cement which
unites them were to become foft; and there.
fore they certainly had not that pofition at the
time when this cement was aQually foft. This
remark has been made by mineralogifts who
were not led to it by any fyftem. The judicious
and indefatigable obferver of the Alps, deferi-
bing the pudding-ftone of Valorfine, near the
fources of the Arve, tells us, that he was
aftonifhed to find it in beds almoft vertical,
a fituation in which it could not poflibly |
have been formed. <“ That particles,” he adds,
“of extreme tenuity, fufpended in a fluid,
might become agglutinated, and form verti-
cal beds, is a thing that may be conceived ;
but that pieces of ftone, of feveral pounds wéigit
fhould have refted on the fide of a perpendicu-
lar wall, till they were enveloped in a ftony
cement, and united into one mafs, is a fuppofi-
tion impoflible and abfurd. It fhould be con-
fidered, therefore, as a thing demonftrated, that
this pudding-ftone was formed in a horizontal
pofition, or one nearly fuch, and elevated after
its induration. We know not,” he continues,
“the force by which this elevation has been
effected ; but it is an important ftep among the
prodigious number of vertical beds that are to
be met with in the Alps, to have found fome

that

HUTTONIAN THEORY. 4y

that muft certainly have been formed in a ho-
rizontal fituation*.”’

41. Nothing can be more found and conclu-
five than this reafoning ; and, had the ingenious
author purfued it more fyftematically, it muft
have led him to a theory of mountains very lit-
tle different from that which we are now en-
deavouring to explain. If fome of the vertical
ftrata are proved to have been formed horizon-
tally, there can be no reafon for not extending
the fame conclufion to them all, even if we had
not the fupport of the argument from the paral-
lelifm of the layers, which has been already fta-
ted.

42. The highly inclined pofition, and the
manifold inflexions of the ftrata, are not the
only proofs of the difturbance that they have
fuffered, and of the violence with which they
have been forced up from their original place.
Thofe interruptions of their continuity which `
are obferved, both at the furface and under it,
are evidences of the fame fact. It is plain, that

if they remained now in the fituation in which

they were at firft depofited, they would never
appear to be fuddenly broken off. No ftratum
would terminate abruptly ; but, however its na-

; ture

* Voyages aux Alpes, tom. ii. § 690.

48 ILLUSTRATIONS OF THE

ture and properties might change, it would con-
flitute an entire and continued rock, at leafi
where the effects of wafte and detritus had not

produced a feparation. This, however, is very

far from being the actual condition of ftratifie
bodies. Thofe that are much inclined, or that
make confiderable angles with the horizontal
plane, muft terminate abruptly where they
come up to the furface. Their doing fo is a ne.
ceffary confequence of their pofition, and furnith-
es no argument, it may be faid, for their having
been difturbed, different from that which has

been already deduced from their inclination,

There are, however, inftances of a breach of con-
tinuity in the ftrata, under the furface, that afford
a proof of the violence with which they have been

difplaced, different from any hitherto mention- |

ed. Of this nature are the /lips or /bifts, that
fo often perplex the miner in his fubterraneous
journey, and which change at once all thofe
lines and bearings that had hitherto dire@ed his
courfe. When his mine reaches a certain plane,
which is fometimes perpendicular, fometimes
oblique to the horizon, he finds the beds of
rock broken afunder, thofe on the one fide of
the plane having changed their place, by fliding
in a particular direction along the face of the
others. In this motion they have fometimes
preferved their parallelifm, that is, the ftrata

on

aune

HUTTONIAN THEORY. 49

on one fide of the /ip continue parallel to thofe
on the other; in other cafes, the ftrata on each
fide become inclined to one another, though
their identity is ftill to be recognifed by their
pollefling the fame thicknefs, and the fame in-
ternal characters. Thefe /bifts are often of
great extent, and muft be meafured by the quan-
tity of the rock moved, taken in conjunétion
with the diftance to which it has been carried.
In fome inftances, a vein is formed at the plane
of the fhift or flip, filled with materials of the
kinds which will be hereafter mentioned ; in
other ‘inftances, the oppofite fides of the rock
remain contiguous, or have the interval between
them filled with foft and unconfolidated earth.
All thefe are the undeniable effects of fome great
convulfion, which has fhaken the very founda-
tions of the earth ; but which, far from being a

diforder in nature, is part of a regular fyftem,

effential to the conftitution and economy of the
globe.

The produétion of the appearances now de-
fcribed, belongs, without doubt, to different pe-
riods of time ; and, where flips interfec& one ano-
ther, we can often diftinguifh the lefs from the
more ancient. They are all, however, of a
date pofterior to that at which the waving and

-undulated forms of the ftrata were acquired,

as they do not carry with them any marks of
D the

so ILLUSTRATIONS OF THE

the foftnefs of the rock, but many of its com.
plete induration.

The fame phenomenon which is thus exem. l
plified on a great fcale in the bowels of the
earth, is often moft beautifully exhibited in fin-

gle fpecimens of ftone, and is accompanied with
this remarkable circumftance, that the inte.
grity of the ftone is not deftroyed by the thifts,
whatever wounds had been made in it being
healed, and the parts firmly re-united to one ano-
ther *.

43. Though fuch marks of violence as have
been now enumerated are common in fome de-
gree to all the ftrata, they abound moft among
the primary, and point out thefe as the part
of our globe which has been expofed to the
greateft viciflitudes. At their junction with the
fecondary, or where they emerge, as it were,
from under the latter, phenomena occur, which
mark fome of thofe viciffitudes with aftonifhing
precifion; phenomena of which the nature was
firft accurately explored, and the confequences
fully deduced, by the geologift whofe fyftem I
am endeavouring to explain. He obferved,
in feveral inftances, that where the primary
{chiftus rifes in beds almoft vertical, it is co-
vered by horizontal layers of fecondary fand-
ftone, which laft are penetrated by the irre-

gular
Note XI.

DETA

—
*

f HUTTONIAN THEORY. 51
1 gular tops of the fchiftus, and alfo involve
x, fragments of that rock; fome angular, others
7 round and {mooth, as if worn by attrition. From
fi this he concluded, that the primary ftrata, after
ii being formed at the bottom of the fea, in planes
i nearly horizontal, were raifed, fo as to become
1i almoft vertical, while they were yet covered by
_ the ocean, and before the fecondary ftrata had
7 begun to be depofited onthem. He alfo argued,
* that, as the fragments of the primary rock, in-
cluded in the fecondary, are many of them
rounded and worn, the depofition of the latter
" muĝ have been feparated from the elevation of
" the former by fuch an interval of time, as gave
room for the a@ion of wafte and decay, al-
lowing thofe fragments firft to be detached, and
afterwards wrought into a round figure *,

t 44. Indeed, the interpofition of a breccia be-
Í tween the primary and fecondary ftrata, in
| which the fragments, whether round or angu-
í dar, are always of the primary rock, is a fa@ fo
" general, and the quantity of this breccia is often
fo great, that it leads to a conclufion more pa-
i radoxical than any of the preceding, but from
| which, neverthelefs, it feems very difficult to
)
|

with-hold affent. Round gravel, when in great
abundance, agreeably to a remark already made,
» muft neceffarily be confidered as a production
j D2 peculiar
* NOTE XIL `

52 ILLUSTRATIONS OF THE |

peculiar to the beds of rivers, or the fhores of È

continents, and as hardly ever formed at great |

depths under the furface of the fea. It thould i

feem, then, that the primary fchiftus, after at.
taining its erect pofition, had been raifed up to
the furface, where this gravel was formed;
and from thence had been let down again o
the depths of the ocean, where the fecondary ;
ftrata were depofited on it. Such alternate
elevations and depreffions of the bottom of
the fea, however extraordinary they may feem,
will appear to make a part of the fyftem of the
mineral kingdom, from other phenomena here-
after to be defcribed. |

45. On the whole, therefore, by comparing
the actual pofition of the ftrata, their eretnek,
their curvature, the interruptions of their con-
tinuity, and the tranfverfe ftratification of the
fecondary in refpect of the primary, with the
regular and level fituation which the fame ftra- |

ta muf have originally poffeffed, we havea f

complete demonftration of their having been
difturbed, torn afunder, and moved angularly,
by a force that has, in general, been directed
from below upwards. In eftablifhing this cot
clufion, we have reafoned more from the facts
which relate to the angular elevation of the fra
ta, than from thofe which relate to their ab
folute elevation, or their tranflation to a great
diftanc?

|

me o.oo eD

E
~

a n a N a a et Se ee enn a ee

HUTTONIAN THEORY. 53

diftance from the centre of the earth. This
has been done, becaufe the appearances, which
trefpect the abfolute lifting up of the ftrata
are more ambiguous than thofe, which refpe&
the change of their angular pofition. The
former might be accounted for, could they be
feparated from the latter, in two ways, viz. ei-
ther by the retreat of the fea, or the raifing up
of the land; but the latter can be explained
only in one way, and force us of neceflity to ac-
knowledge the exiftence of an expanding power,
which has acted on the ftrata with incredible
energy, and has been directed from the centre |
toward the circumference.

46. When we are affured of the exiftence of
fuch a power as this in the mineral regions, we
fhould argue with fingular inconfiftency if we
did not afcribe to it all the other appearances
of motion in thofe regions, which it is adequate
to produce. If nature in her fubterraneous a-
bodes is provided with a force that could burft
afunder the maffy pavement of the globe, and
place the fragments upright upon their edges,
could fhe not, by the fame effort, raife them
from the greateft depths of the fea, to the high-
eft elevation of the land? The caufe that is ade-
quate to one of thefe effedts, is adequate to them
both together; for it is a principle well known
in mechanical philofophy, that the force which

D3 produces

s4 ILLUSTRATIONS OF THE

produces a parallel motion, may, according to —

the way in which it is applied, produce alfo an
angular motion, without any diminution of the
former effet. It would, therefore, be extreme.
ly unphilofophical to fuppofe, that any other
caufe has changed the relative level of the ftra-

ta, and the furface of the fea, than that which —

has, in fo many cafes, raifed the ftrata from a
horizontal to a highly inclined, or even verti-
cal fituation: it would be to introduce the ac-
tion of more caufes than the phenomena re-
quire, and to forget, that nature, whofe opera-
tions we are endeavouring to trace, combines
the poffeffion of infinite refources with the moft
economical application of them.

47. From all, therefore, that relates to the
pofition of the ftrata, I think I am juftified in
affirming, that their difturbance and removal
from the place of their original formation, by a
force directed from below upwards, is a fact in
the natural hiftory of the earth, as perfedtly
afcertained as any thing which is not the fub-
ject of immediate obfervation. As to the
power by which this great effet has been
produced, we cannot expect to decide with
equal evidence, but muft be contented to:pals
from what is certain to what is probable. We
-may, then, remark, that of the forces in nature
to which our experience does in any degree a

tend,

F)

———

k

Í HUTTONIAN THEORY. 55

tend, none feems fo capable of the effect we
ty would afcribe to it, as the expanfive power of
the heat ; a power to which no limits can be fet, and
NM, one, which, on grounds quite independent of the
her elevation of the ftrata, has been already conclu-
m ded to ad with great energy in the fubterra-
ij neous regions. We have, indeed, no other al-

lj ternative, but either to adopt this explanation,

fi or to afcribe the facts in queftion to fome fecret

a and unknown caufe, though we are ignorant of
its nature, and have no evidence of its exift-

m ence. |

m Weare therefore to fuppofe, that the power

of of the fame fubterraneous heat, which con-
= folidated and mineralized the ftrata at the
4, bottom of the fea, has fince raifed them up to
the height at which they are now placed, and
y, as given them the various inclinations to the
horizon which they are found actually to pof-

f es

t 48. The probability of this hypothefis will be
fi greatly increafed, when it is confidered, that, be-
of fides thofe now enumerated, there are other indi-
j = cations of movement among the bodies of the mi-
i = neral kingdom, where effeéts of heat more cha-
A racteriftic than fimple expanfion are clearly to
i be difcovered. Thus, on examining the marks of
; diforder and movement which are found among

the ftrata, it cannot fail to be obferved, that not-
i D4 withftanding

s6 ILLUSTRATIONS OF THE

withftanding the fracture and diflocation, of
which they afford fo many examples, there are
few empty {paces to be met with among them,
as far as our obfervation extends. The breach.
es and feparations are numerous, and difting ;
but they are, for the moft part, completely fill.
ed up with minerals of a kind quite different
from the rock on each fide of them, and re-
markable for containing no veftiges of ftratifi-
cation. We are thus led to confider the unftra-
tified foffils, the fecond of the divifions into which
the whole mineral kingdom, viewed geological-
ly, ought to be diftinguifhed. Thefe foffils are
, immediately connected with the difturbance of
the ftrata, and appear, in many inftances, tq
have been the inftruments of their elevation.

SEQ

p
a S
l

Ce A

EER

HUTTONIAN THEORY. 57

SEC TION IL

' QF THE PHENOMENA PECULIAR TO UNSTRATI-

FIEÐ BODIES.
t. Metallic Veins.

49. HE unftratified minerals exift either in
veins, interfecting the ftratified, or in
maffes furrounded by them. Veins are of va-
rious kinds, and may in general be defined, fe-
parations in the continuity of a rock, of a deter-
minate width, but extending indefinitely in
length and depth, and filled with mineral fub-
ftances, different from the rock itfelf. The mi-
neral veins, ftrictly fo called, are thofe filled
with fparry or cryftallized fubftances, and con-
taining the metallic ores.
That thefe veins are of a formation fubfe-
quent to the hardening and confolidation of the

ftrata which they traverfe, is too obvious to re-

quire any proof; and it is no lefs clear, from
the cryftallized and fparry ftructure of the fyb-
ftances contained in them, that thefe fubftances
muft have concreted from a fluid ftate. Now,
that this fluidity was fimple, like that of fufion
by heat, and not compound, like that of folu-
tion in a menftruum, is inferred from many phe-
nomena. It is inferred from the acknowledged

infolubility

w

58 ILLUSTRATIONS OF THE

infolubility of the fubftances that fill the veins,
in any one menftruum whatfoever ; from the
total difappearance of the folvent, if there was
any ; from the complete filling up of the vein by
the fubftances which that folvent had depofited ;
from the entire abfence of all the appearances
of horizontal or gradual depofition ; and, laftly,
from the exiftence of clofe cavities, lined with
cryftals, and admitting no egrefs to any thing
but heat,

50. Tothe fame effe& may be mentioned thofe
groups of cryftals compofed of fubftances the

moft different, that are united in the fame fpe-

cimen, all interfecting and mutually imprefling
one another. Thefe admit of being explained, on
the fuppofition that they were originally in fu-
fion, and became folid by the lofs of heat; a
caufe that acted on them all alike, and alike im-
pelled them to cryftallize : But the appearances
of fimultaneous -cryftallization feem incompati-
ble with the nature of depofition from a folvent,
where, with refpect to different fubftances, the
effects muft take place flowly, and in fucceflion.
51. The metals contained in the veins which
we are now treating of, appear very commonly
in the form of an ore, mineralized by fulphur.
Their union with this latter fubftance can be
produced, as we know, by heat, but hardly by
the way of folution in a menftruum, and cer-
tainly

j
)

—

r AEREI DIENE,

diii

HUTTONIAN THEORY. 59

tainly not at all, if that menftruum is nothing
elfe than water. The metals, therefore, when
mineralized by fulphur, give no countenance to
the hypothefis of aqueous folution ; and ftill lefs
do they give any when they are found native, as
it is called, that is, malleable, pure and uncom-
bined with any other fubftance. The great maf-

fes of native iron found in Siberia and South

America are well known; and nothing certain-
ly can lefs refemble the produdts of a chemical
precipitation. Gold, however, the moft perfect of
the metals, is found native moft frequently ; the
others more rarely, in proportion nearly to the fa-
cility of their bination with fulphur. Of all
fuch {pecimens it may bė fafely affirmed, that if
they have ever been fluid, or even foft, they muft
have been fo by the action of heat ; for, to fup-
pofe that a metal has been precipitated, pure and
uncombined from any menftruum, is to trefpafs
againft all analogy, and to maintain a phyfical
impoflibility. But it is certain, that many of
the native metals have once been in a ftate of
foftnefs, becaufe they bear on them impreffions
which they could not have received but when
they were foft. Thus, gold is often imprefled
by quartz and other ftones, which ftill adhere
to it, or are involved init. Specimens of quartz,
containing gold and filver fhooting through

them,

60 ILLUSTRATIONS OF THE

them, with the moft beautiful and varied ramif.
cations, are every where to be met with in the
cabinets of the curious ; and contain, in their
ftructure, the cleareft proof, that the metal and
the quartz have been both foft, and have cry.
ftallized together. By the compaétnefs, alfo, of
the body which they form, they fhow, that
when they acquired folidity, it was by the con-
cretion of the whole mafs, and not by fuch par-
tial concretion as takes place when a folvent
is feparated from fubftances which it held in fo.
lution.

52. Native copper is very abundant; and
fome {pecimens of it have been found cryftal-
lized. Here the cryftallization of the metal is
a proof that it has paffed from a fluid to a fo-
lid ftate ; and its purity is a proof that it did
not make that tranfition by being precipitated
from a menftruum,.

53. Again, pieces of native manganefe have
been found poileffing fo exaétly the charadters
peculiar to that metal when reduced in our fir-
naces, that it is impoflible to confider them as
deriving their figure and folidity from any caufe
but fufion. The ingenious author who de-
icribes thefe {pecimens, La Peyroufe, was fo
forcibly’ ftruck with this refemblance, that he
immediately drew the fame conclufion from it
which is drawn here, attributing the only differ-

ence,

HUTTONIAN THEORY. 6r.

ence, which he remarked between the native
and the artificial regulus, to the different energy
with which the fame agent works when em-
ployed by nature and by art *.

54. All thefe appearances confpire to prove,
that the materials which fill the mineral veins
were melted by heat, and forcibly injected, in
that ftate, into the clefts and fiffures of the ftra-
ta. Thefe fiflures we muft conceive to have
arifen, not merely from the fhrinking of the
ftrata while they acquired hardnefs and folidity,
but from the violence done to them, when they
were heaved up and elevated in the manner
which has already been explained +.

53. When thefe fuppofitions are once admit-
= ted, the other leading facts in the hiftory of me-
tallic veins will be readily accounted for. Thus,
for inftance, it is evident to what we muft-
afcribe the fragments of the furrounding rock
that are often found immerfed in the veins, and
encompaffed on all fides by cryftallized fubftan-
ces. Thefe fragments being no doubt detached
“by the concuffion, which at once tore afunder
and elevated the ftrata, were fuftained by the
melted matter that flowed at the fame time up-

ward

* Theory of the Earth, vol. i. p. 68. . Journal de Phyf.
Janvier 1786.

+ NOTE XIII.

62 ILLUSTRATIONS OF THE

ward through the vein. Large maffes of rock
are often found in this manner completely in.
{ulated ; one of thefe, which M. de Luc has
deicribed with great accuracy, is no lefs than a
vaft fegment of a mountain *.

50. The immenfe violence which has accom:
panied the formation of mineral veins, is parti-
cularly marked by the flips and fhifts of the ftra-
ta on each fide of them, all tending to fhow
what mighty changes have taken place in thofe
regions, which our imagination erroneoufly
paints as the abode of everlafting filence and
reft. This fhifting of the ftrata is beft obfer-
ved, where the veins make a tranfverfe fe&tion
of beds of rock, confiderably inclined to the
horizon. There it is common to fee the beds
on one fide of the vein flipped along from
the correfponding beds on the other fide, and
removed fometimes in a horizontal, fometimes in
an oblique direGion. In this way, not only
the ftrata are fhifted, but veins, which inter-
fect one another, are alfo fhitted themfelves,
They are heaved, as it is called in the figni-
ficant language of the miners, and forced out
of their dire&tion. It is impoflible, in fuch a

cafe, but to conned in the mind the formation —

of

* Lettres Payfiques, &c, tom. ili, p. 361.

> ee a Re. ee Se yt OS RS ge ga ee een ee

ae

HUTTONIAN THEORY. 63

of the vein, and the production of the flips which
accompany it, and to regard them as parts of
the fame phenomenon.

57. Where thefe flips are horizontal, and ex-
hibit great bodies of ftrata carried from their
place, while the parts of the transferred mafs re-
main undifturbed relatively to one another, they

` furnifh a clear proof, that this change of place has

not arifen from the falling in of the roofs of ca-
verns, as fome geologifts fuppofe. The horizontal
direction, and the regularity of the movement,
are incompatible with the adtion of fuch a caufe
as this; and indeed it is highly interefting to re-
mark, in the midft of the figns of difturbance
which prevailinthe bowels of the earth, that there
reigns a certain fymmetry and order, which in-
dicate the action of a force of incredible magni-
tude, but flow and gradual in its effets. The
parts of the mafs moved are undifturbed rela-
tively to one another: what has been broken
has been cemented: the breaches of continuity

-have been filled up and healed ; and every where

we fee the operation of a caufe that could unite

as well as feparate. The twofold action of heat

to expand and to melt, could fcarce be pointed
out more clearly by any fyftem of appearan-

58. As a long period was no doubt required
for the elevation of the ftrata, the rents made

in

64 ILLUSTRATIONS OF THE

in them are not all of the fame date, nor the
veins all of the fame formation. This is clear
in the cafe of one vein producing a thift or
flip in another; for the vein which forces the
other out of its place, and preferves its own di.
_ rection, is evidently the more recent of the two,
and muft have had its materials in a ftate of ac.
tivity, when thofe of the other were inert. Some.

times, alfo, at the interfection of two veins, we —

may trace the current of the materials of the
one, acrofs thofe of the other; and here, of
confequence, the relative antiquity is determi-
ned juft as in the former inftance.

59. The want of any appearance of fteatifica
tion in mineral veins has already been taken
notice of. There is, however, to be obferved,
in many inftances, a tendency to a regular ar-
rangement of the fubftances contained in them;
thofe of the fame kind forming coats parallel to
the fides of the vein, and nearly of an equal thick-
nefs. This phenomenon is confidered as one of
the itrongeft arguments in favour of the Neptu-
nian fyftem, but has nothifig in it, in the leaft in-
compatible with that theory which afcribes the

formation of veins to. the action of fubterraneous.

heat. When melted matter from the mineral re-
gions was thrown up into the veins, that which
was neareft to the fides would fooneft lofe its heat.
The fimilar fubftances, alfo, would unite while

this

A

O

HUTTONIAN THEORY. 6s

-this procefs was going forward, and would cry-

ftallize, as in other cafes of congelation, from the
fides toward the interior. Therg is the more rea-
fon for fuppofing this to have been the cafe, that
the fame fort of coating is often obferved on
the infide of clofe cavities, which are, neverthe-
lefs, fo conftruéted, as to afford a demonttration
that no chemical folvent was ever included in

them, (§ 74.). Some veins, it muft alfo be con-

fidered, may have been filled by fucceflive in-

jeCtions of melted matter, and this would natu-
rally give rife to a variety of feparate incrufta-

tions *, E

6o. In the view now given of metallic veins,

they have been confidered as traverfing only the

ftratified parts of the globe. They do, however,

occafionally interfe& the unftratified parts, par-

ticularly the granite, the fame vein often conti.

nuing its courfe acrofs rocks of both kinds, with-

out fuffering any material change ; and, if we

have hitherto paid no attention to this circum-~

ftance, it is becaufe the order purfued in this

effay required, that the relation of the veins to

ftratified bodies fhould be firft treated of. Be-

fides, the facts in the natural hiftory of veins,
whether contained in ftratified or unftratified
rocks,

* See fome farther remarks on this fubje&t at Noreg
XIII.

66 ILLUSTRATIONS OF THE

rocks, are fo nearly alike, that in a general view
of geology, they do not require to be diftin.
guifhed. It is material to remark, that, though
metallic veins are found indifcriminately in all
the different kinds of rock, whether ftratified or

otherwife, they are moft abundant in the clab _
of primary {chifti. All the countries moft re. —

markable for their mines, and the mountains

diftinguifhed by the name of metalliferous, are —
_ primary, and the inftance of Derby thire is per-
haps the moft confiderable exception to this rule,

that is known. This preference, which the
metals appear to give to the primary ftrata, is

very confiftent with Dr Hutton’s theory, which —
reprefents the rocks of that order as being mok —
changed from their original pofition, and thofe |

on which the difturbing forces of the fubterra-
neous regions have acted moft frequently, and

with greateft energy. The primary ftrata are

the loweft, alfo, and have the moft dire& com-
munication with thofe regions from which the
mineral veins derive all their riches.

4, OF. Whin one.

61. Befide the veins filled with fpar, and com |

taining the metallic ores, the ftrata are interfed-
ed by veins of whinftone, porphyry and granite,
the

— ——

— NSR

= Rema ae Pict ae ae = ee

-HUTTONIAN THEORY. 6y
the characters of which are next to be exami-
ned.

The term whin, or whinftone, with Dr Hut-
ton, like the word trap, with the German mine-
ralogifts, denotes a clafs of ftones, comprehend-
ing feveral diftiné fpecies, or at leat varieties.
The common dba/alz, the wacken, mullen, and
crag of Kirwan, the grinftein of Werner, and
the amygdaloid, are comprehended under the
name of whin. All thefe ftones have a ten-
dency to a f{pathofe: ftruture, and difcover at
leat The rudiments of eryftallization. They
are, at the fame time, without any mark of
ftratification in their internal texture, as they
are alfo, for the moft part, in their outward cons
figuration; ahd, as the different fpecies here
enumerated compofe, not unfrequently, parts of
the fame continuous rock, the change from one
to another being made through a feries of in-
fenfible gradations, they may fafely be regard-
ed by the geologift as belonging to the fame

E genus.

62. Whin, though not ftratified, exifts in two
different ways, that is, either in veins, (called in
Scotland dykes), traverfing the ftrata like the

_ Veins already defcribed, or in irregular maffes,

incumbent on the ftrata, and fometimes inter-
pofed between them. In both thefe forms,
whinftone has nearly the fame charaCers, and

E2 bears,

68 ILLUSTRATIONS OF THE

bears, in all its varieties, a moft ftriking refem.

blance to the lavas which have actually floweg

from volcanoes on the furface of the earth,
This refemblance is fo great, that the two fub.
ftances have been often miftaken for one ano.
ther; and many rocks, which have been pro.
nounced to be the remains of extinguifhed vol.

canoes, by mineralogifts of no inconfiderable —

name, have been found, on clofer examination,
to be nothing elfe than maffes or veins of whin-

ftone. This latter ftone is indeed only to be

diftinguifhed from the former, by a careful ex-
amination of the internal characters of both;
and chiefly from this circumftance, that whin-
ftone often contains calcareous {par and zeolite,
whereas neither of thefe fubftances is found in
fuch lavas, as are certainly known to have been
thrown out by volcanic explofions. |

Now, from thefe circumftances of affinity be-
tween lava and whinftone, on the one hand, and
of diverfity on the other, as the formation of
the one is known, it fhould feem that fome pro-
bable conclufion may be drawn concerning the
formation of the other. The affinity in que-
ftion is conftant and effential; the difference
variable and accidental; and this naturally leads
to fufpect, that the two ftones have the fame
origin; and that, as lava is certainly a produc-

tion of fire, fo probably is whinftone.
63. But

—
_—

on
— m
m Py e ES ey a eee

a

Ss

HUTTONIAN THEORY. 69

63. But, in order to fee whether this hypo-
thefis will explain the diverfity of the two fub-
ftances, without which it will not be entitled
to much attention, we muft remark, that the
prefence of carbonat of lime in a body that has _

been fufed, argues, agreeably to the principles
formerly explained, that the fufion was brought

about under a great comprefling force, that is
to fay, deep in the bowels of the earth, or in the
great laboratory of the mineral regions. We-
are, therefore, to fuppofe that the fufion of the
whin was performed in thofe regions, where the
compreffion was fufficient to preferve the car-
bonic gas in union with the calcareous earth,
fo that thefe two fubftances melted together,
and, on cooling, cryftallized into fpar. In
the lavas, again, thrown out by volcanic erup-
tion, the fufion, as we know, wherever it may
begin, continues in the open air, where the pref-
fure is only that of the atmofphere: the calca-
reous earth, which, therefore, may have been,
in the form of a carbonat, among the materials
of this lava, muĝ be converted into quicklime,
and become infufible ; hence the want of calca-
reous {par in lavas that have flowed at the fur-
face.

Thus, whinftone is to be accounted a fubter-
raneous, or wi-erupted lava ; and our theory has
the advantage of explaining both the affinity

E3 and

40 ILLUSTRATIONS OF THE

and the difference between thefe ftony bodies,
without the introduction of any new hypothe.
fis. In the Neptunian fyftem, the affinity of
whinftone and lava is a paradox which admits
of no folution.

64. The columnar ftru@ure fometimes found
in that fpecies of whinttone called bafaltes, is a
fact which has given rife to much difcuffion ;
and it muft be confeffed, that though one of the

moft ftriking and peculiar charaers of this ;
fofiil, it is not that which gives the cleareft and —

moft direct information concerning its origin,
One circumftance, however, very much in fa-

vour of the opinion that bafaltic rocks owe

their formation to fire, is, that the columnar
form is fometimes affumed by the lava adual-
ly erupted from volcanoes. Now, it is cer-
tainly of no fmall importance, to have the
fynthetic argument on our fide, and to know,
that bafaltic columns can be produced by
fire; though, no doubt, to give abfolute cer-
tainty to our conclufion, it would be necef-
fary to fhow, that there are in nature no other
means but this by which thefe columns can
be formed. This fort of evidence is hard-
ly to be looked for; but fince the power of
fufion, to produce the phenomena in queftion,
is perfectly eftablifhed, and fince the production
of the fame phenomena in the humid way is 4

mere

p
_—

ee es

—

HUTTONIAN THEORY. yr

mere hypothefis, if there be the leaft reafon to
fufpect the ation of fubterraneous heat as one
of the caufes of mineralization, very maxim
of found philofophy requires that the bafaltic
flruQure, in all cafes, fhould be afcribed to it.
65. The Neptunifts will no doubt allege, with
Bercman, that, in the drying of ftarch, clay,
and a few other fubftances, fomething analogous

tk to bafaltic columns is produced. Here, how-

ever, a moft important difference is to be re-
marked, correfponding very exactly to one of
the characters which we have all along obfer-
ved to diftinguifh the products of aqueous, from
thofe of igneous confolidation. ‘The columns
formed by the fubftances juft mentioned, are di-
ftant from one another: they are feparated by

-fiffares which widen from the bottom to the top,

and which arife from the fhrinking and dry-
ing of the mafs. In the bafaltic columns, no
fuch openings, nor vacuity of any kind is found ;
the pillars are in contact, and, though perfectly
diftin@, are fo clofe, that the fharp edge of a

wedge can hardly be introduced between them.

Chis is a great peculiarity in the bafaltic ftruc-
ture, and is ftrongly expreffive of this fac, that
the mafs was all fluid together, and that its parts
took their new arrangement, not in confequence
of the feparation of a fluid from a folid part, by
Which great fhrinking and much empty fpace

E4 might °

72 ILLUSTRATIONS OF THE

might be produced; but in confequence of a
caufe which, like refrigeration, acted equally on
all the parts of the mafs, and preferved their
abfolute contact after their fluidity had ceafed.
66. A mark of fufion, or at leaft of the ope.
ration of heat, which whinftone poffeffes in com.
mon with many other minerals, is its being pe-
netrated by pyrites, a fubftance, as has been al.

ready remarked, that is of all others moft ex. _
clufively the produdtion of fire. Another mark |

of fufion, more diftin@tive of whin, is, that both

in veins and in maffes it fometimes includes Pieces |

of fandftone, or of the other contiguous ftrata,
completely infulated, and having the appearance
of fragments of rock, floating in a fluid fuffi-
ciently denfe and ponderous to fuftain their

weight. ‘Though thefe fragments have been —

too refractory to be reduced into fufion them-
felves, they have not remained entirely un-
changed, but are, in general, extremely indu-
rated, in comparifon of the rock from which
they appear to have been detached.

67. Similar inftances of extraordinary indu-

ration are oblerved in the parts of the ftrata in

contact with whinftone, whether they form the
fides of the veins, or the floors, and roofs of the
mafles into which the whinftone i is diftributed.

The ftrata whether fandy or argillaceous, in
fuch fituations, are ufually extremely hard and

confolidated 5

a

aes

a ee ee ee ee ee

ps

HUTTONIAN THEORY. 74

eonfolidated ; the former in particular lofe their
granulated texture, and are fometimes convert-
ed into perfect jafper. This interefting remark
was firft made by Dr Hutton, and the truth of

it has been verified by a great number of fub-

fequent obfervations.

68. To the fame excellent Picci we are
indebted for the knowledge of an analogous fac,
attendant on the paflage of whinftone veins
through coal ftrata. As the beds of ftone where
they are in contact with veins of whin, feem to
acquire additional induration, fo thofe of coal,
in like circumftances, are frequently found to
have loft their fufibility, and to be reduced near-
ly to the condition of coke, or of charcoal. The
exiftence of coal of this kind has been already

_ Mentioned, and confidered as a proof of the ope-

ration of fubterraneous heat. In the inftances
here referred to, that is, where the charring of
the coal is limited to thofe parts of the ftrata
which are in contac&t with the whin, or in its im-
mediate vicinity, the heat is pointed out as re-
fiding in the vein; and this is to be accounted
for only on the {uppofition of the melted whin,
at a period fubfequent to the confolidation of
the coal, having flowed through the openings of
the ftrata. The heat has been powerful enough,
in many cafes, to drive off the bituminous matter
of the coal, and to force it into colder and more
diftant

74 ILLUSTRATIONS OF THE

diftant parts. Few facts, in the hiftory of fofils,
are more remarkable than this, and none more
dire@ly affimilates the operatioris of the mineral
regions, with thofe that take place at the furface
of the earth. |

69. Again, the difturbance of the ftrata,
wherever veins of whinftone abound, if not a

direct proof of the original fluidity of the whin. 1

ftone, is a clear indication of the violence with
which it was introduced into its place. This di-
fturbance of the pofition of the ftrata, by fhift.
ing, unufual elevation, and other irregularities,
where they are interfected by whinftone veins,
is a fact fo well known to miners, that when

they meet with any fudden change in the lying
of the metals, they are wont to foretel their ap-

proach to maffes, or veins of unftratified matter;
and, in their figurative language, point them
out as the caufes of the confufion with which

they are fo generally accompanied *. The mi-

neral veins likewife, as well as the ftrata, are
often heaved and fhifted by the veins of whin-
ftone.

70. Whinftone of every fpecies is found fre
quently interpofed in tabular maffes, between
beds of ftratified rocks ; and it then adds to the

indications

* A Trouble is the name which the colliers in this

country give to a vein of whinftone.

re i log-

ae

cic cae

SS See SS. Set. Reese
z? ci “>:

oe

HUTTONIAN THEORY. T

indications of its igneous origin, already enume-
rated, fome others that are peculiar to it when
in this fituation. In fuch inftances, it is not un-
common to find the ftrata in fome places, conti-

guous to the whin, elevated, and bent with their

concavity upward, fo that they appear clearly to
have been acted on by a force that proceeded
from below, at the fame time that they were
foftened, and rendered in fome degree flexible:

jt is needlefs to remark, that thefe effeGs can

be explained by nothing but the fufion of the
whin ; ~and that the great force with which it was
impelled againft the ftrata, could be produced
by no caufe but heat, acting in the manner that
is here fuppofed.

71. Again, if it be true that the maffes of
whin, thus interpofed among the ftrata, were
introduced there, after the formation of the lat-
ter, we might expect to find, at leaft in many in-
ftances, that the beds on which the whinftone
refts, and thofe by which it is covered, are exa@t-
ly alike. Ifthete beds were once contiguous, and
have been only heaved up and feparated by the

irruption of a fluid mafs of fubterraneous lava, -

their identity fhould ftill be recognifed. Now,
this is precifely what is obférved ; it is known
to hold in a vaft number of inftances, and is
ftrikingly exemplified in the rock of Salifoury
Crag, near Edinburgh.

: This:

“6 ILLUSTRATIONS OF THE

This fimilarity of the ftrata that cover the
maffes of whinftone, to thofe that ferve as the
bafe on which they reft, and again the diffimilj.
tude of both to the interpofed mafs, are fa@s
which I think can hardly receive any explana.
tion, on the principles of the Neptunian theory,
If thefe rocks, both ftratified and unttratified, are

to he regarded as productions of the fea, the

circumftances would require to be pointed out,
which have determined the whinftone, and the
‘beds that are all round it, to be fo extremely
unlike in their ftru@ure, though formed at the
fame time, and in the immediate vicinity of one
another ; as alfo thofe circumftances, on the other
hand, which determined the ftratified depofites
above and below the whinftone, to be precifely
the fame, though the times of their formation
muft have been very different. The homo-
geneous fubftances, thus, placed at a diftance,

and the heteroge brought fo clofely toge-

ther, are phenomena equally unaccountable, in a
theory that afcribes their origin to the operation
of the fame element, and that neceflarily dates
their formation according to the order in which
they lie, one above another.

72. If, indeed, in thefe inftances, the grada-
tion were infenfible, as fome have afferted it to

be, between the ftrata and the interpofed mafs,

fo that it was impoflible to point out the line
where

ai

r

HUTTONIAN THEORY: 77

where the one ended and the other began, what-
ever difficulties we might perceive in the Nep-
tunian theory, we fhould find it hard to fubfti-
tute a better in its room. But the truth feems
to be, that, in the cafes we are now treating of,
no fuch gradation exifts; and that, though
where the two kinds of rock come into contact
a change is often obferved, by the ftrata having
acquired an additional degree of induration, yet
the line of feparation is well defined, and can
be precifely afcertained. This at leaft is cer-
tain, that innumerable fpecimens, exhibiting ©
fuch lines of feparation, are to be met with; and
wherever care has been taken to obtain a frefh
fracture of the ftone, and to remove the effects
of accidental caufes, even where the two rocks are
moft firmly united, and moft clofely affimilated,
I am perfuaded that no uncertainty has ever re-
mained as to the line of their feparation. For
thefe reafons, it feems probable that the gradual
tranfition of bafaltes into the adjoining ftrata, is
in all cafes imaginary, and is, in truth, a mere il-
lufion, proceeding from hafty and inaccurate
obfervation. |

73. Another remarkable fact in the natural
hiftory of the whinftone rocks, remains yet to be

_ mentioned, and with it I fhall conclude the ar-
gument, as far as thefe rocks are concerned.

Some

58 ILLUSTRATIONS OF THE

Some of the fpecies of whinftone are the
common matrices of agates and chalcedonies,
which lie inclofed in them in the form of
round nodules. The original fluidity of thefe
nodules is evinced by their figured, and fome-
times cryftallized ftru&ure, and indeed is fo ge-
nerally admitted, that the only queftion con-

cerning them is, whether this fluidity was the i

effect of heat or of folution. To anfwer this
queftion, Dr Hutton obferves, that the forma-
tion of the concentric coats, of which the agate
is ufually compofed, has evidently proceeded
from the circumference toward the centre, the
exterior coats always imprefling the interior,
but never the reverfe. The fame thing alfo fol-
lows from this other faét, that when there is
_ any vacuity within the agate, it is ufually at
the centre, and there too are found the regu-
lar cryftals, when any fuch have been forme
ed. It therefore appears certain, that the pro-
grefs of confolidation has been from the circum:
ference inwards, and that the outward coats of

the agate were the firt to acquire folidity and

hardneis.

74. Now, it muft be confidered that thefe coats
are highly confolidated ; that. they are of very
pure filiceous matter, and are utterly impervious
to every fubitance which we know of, except
light and heat. It is plain, therefore, that what-

ever

P Da e

p fomai Bese hd Dag Aid ee. eee ae Na: ee

HUTTONIAN THEORY. 79

ever at any time, during the progrefs of confo-
lidation, was contained within the coats already
formed, muft have remained there as long as the
agate was entire, without the leaft poffibility of
efcape. But nothing is found within the coats
of the agate fave its own fubftance; therefore
no extraneous fubftance, that is to fay no fol-
vent, was ever included withinthem. The flui-
dity of the agate was therefore fimple, and un-
aflifted by any menftruum.

In this argument, nothing appears to me

-~ wanting, that is neceflary to the perfection of a

phyfical, I had almoft faid of a mathematical,
demonftration. It feems, indeed, to be impof-
fible that the igneous origin of foffils could be
recorded in plainer language, than by the phe-
nomenon which has juft been defcribed.

7g.) Lhe ination of particular {pecimens of
agates and chalcedonies, affords many more ar-
guments of the fame kind, which Dr Hutton
ufed to deduce with an acutenefs and vivacity,
which his friends have often liftened to with
great admiration and delight *. Thefe, however,
muft be pafled over at prefent ; and I have on-
ly further to remark, that a feries of the moft
interefting experiments, inftituted by Sir Jams
Hatt, and publithed in the Tranfactions of the
Royal Society of Edinburgh +, has removed the
: only

* Nove xiv. + Vol. v. p. 43.

86 ILLUSTRATIONS OF THE

only remaining objection that could be urged
againft the igneous origin of whinftone. This
objection is founded on the common obferva-
tion, that when a piece of whinftone or bafaltes
is actually melted in a crucible, on cooling, it

becomes glafs, and lofes its original character en. _

tirely ; and from thence it was concluded, that
this character had not been originally produ-

ced by fufion. The experiments above men. |

tioned, however, have fhewn, in the mof fa-
tisfactory manner, that melted whin, by regu-
lated or by flow cooling, is prevented from affu-
ming the appearance of glais, and becomes a fto-
ny fubftance, hardly to be diftinguifhed from
whinftone or lava. ` :

The experiments of another ingenious che-

mit, Dr Kennepy, have fhewn, that whinftone
contains mineral alkali, by which, of courfe, its
fufion muft have been affifted *. Dr Hutton ufed
to afcribe its fufibility, in a great meafure at
leaft, to the quantity of iron contained in it:
both thefe caufes have no doubt united to ren-

der it more eafily melted than the ordinary ma-

terials of the ftrata.

76. Ina word, therefore, to conceive aright the
origin of that clafs of unftratified rocks, diftin-
guifhed by the name of whinftone, we muft fup-

pofe,

* Tranf. R, S. Edin. vol. v, p: 85.

HUTTONIAN THEORY. Sr

pofe, that long after the confolidation of the
ftrata, and during the time of their elevation,
the materials of the former were melted by the
force of fubterraneous heat, and injected among
the rents and fiffares of the rocks already formed.
In this manner were produced the veins or dikes
of whinftone ; and, where circumftances allow-
ed the ftream of melted matter to diffufe itfelf
more widely, tabular maffes were formed, which
were afterwards raifed up, together with the
furrounding ftrata, above the level of the fea,
and have been fince laid open by the operation
of thofe caufes that continually change and
watte the furface of the land. |

Thefe unftratified rocks are not, however, all
the work of the fame period 3 they differ evi-
dently in the date of their formation, and it is
not unufual, to find tabular maffes of one fpe-
cies of whin, interfeéted by veins of another
fpecies. Indeed, of all the foffil bodies which
compofe the prefent land, the veins of whin ap-
pear to be the moft recently confolidated *.

- Porphyry may fo properly be regarded asa
variety of whin, diftinguifhed only by involv-
ing cryftallized feltfpar, that, in a geological
fketch like the prefent, it is hardly entitled to
a feparate article. Like the other kinds of

F whin,

* NoTE xiv,

=

82 ILLUSTRATIONS OF THE

whin, it exifts both in veins and in tabular
maffes, having, no doubt, an origin fimilar to
that which has juft been defcribed. Porphyry,
however, has the peculiarity of being rarely
found in any but the primary ftrata; it feems
to be the whinftone of the old world, or at leat
that which is of higheft antiquity in the prefent,
It no-where, I believe, aflumes a columnar, or
bafaltic appearance, of any regularity ; but this
is alfo. true of many other varieties of whin, of
all, indeed, except the moft compact and ho-
mogeneous. ‘Thefe differences are not fo`con-
fiderable as to require our entering into any
particular detail concerning the natural hiftory
of this foffil. 7

3. Granite.

77. The term Granite is ufed by Dr Hutton
to fignify an aggregate ftone, in which quartz,
feltfpar and mica are found diftiné from one
another, and not difpofed in layers. ‘Fhe addi
tion of hornblend, {chorl, or garnet, to the three
ingredients juft mentioned, is not underftood to
alter the genus of the ftone, but only to confti-

‘tute a fpecific difference, which it is the bufinefs

of lithology to mark by fome appropriate cha-
racter, annexed to the generic name of granite.
The

lis

eee ee

a

ae ee

TERSA

HUTTONIAN THEORY. 83

The foffil now defined exifts, like whinftone
and porphyry, both in maffes and in veins,
though moft frequently in the former. It 1s
like them unftratified in its texture, and is re-
garded here, as being alfo unftratified in its out-
ward ftructure *. One ingredient which is efen-
tial to granite, namely, quartz, is not contained.
in whinftone; and this circumftance ferves to

~ diftinguifh thefe genera from one another,

though, in other refpects, they feem to be uni-
ted by a chain of infenfible gradations, from the
, F 2 moft

* Thofe rocks that confift of the ingredients here enu-
merated, if they have at the fame time a fchiftofe tex-
ture, or a difpofition into layers, are properly diftin-
guifhed from granite, and called Gneifs, or Granitic
Schiftus. But it has been queftioned whether a ftone
does not exift compofed of thefe ingredients, and defti-
tute of a {chiftofe texture, but yet divided into large
beds, vifible in its external form. Dr Hutton fuppofes
fuch a ftone not to exift, or at leaft not to conftitute any

fuch proportion of the mineral kingdom, as to entitle it
_ to particular confideration, in the general {peculations of

geology.

Whether this fuppofition is perfe&ly corre, may re-
quire to be farther confidered: this, however, is certain,
that a rock, in ali refpe&s conformable to it, compofes a
great proportion of what are ufually called the granite
mountains, See NOTE xv.

$4 ILLUSTRATIONS OF THE

moft homogeneous bafaltes, to granite the mog
highly cryftallized.

78. Granite, it has been juft faid, exifts moft
commonly in mafles ; and thefe mafles are rare-
ly, if ever, incumbent on any other rock : they
are the bafis on which others reft, and feem, for
the mof part, to rife up from under the ancient,
or primary ftrata. The granite, therefore,
wherever it is found, is inferior to every other
rock ; and as it alfo compofes many of the great-

eft mountains, it has the peculiarity of being eles _

vated the higheft into the atmofphere, and funk

the deepeft under the furface, of all the mineral

fubftances with which we are acquainted.
Notwithftanding the circumftance of not be-

ing alternated with ftratified bodies, which

conftitutes a remarkable difference between gra-

nite and whinftone, the affinity of thefe foffils is
fuch as to make the fimilarity of their origin by
no means improbable. Accordingly, in Dr

Hutton’s theory, granite is regarded as a ftone
of more recent formation than the ftrata incum-
bent on it ; as a fubftance which has been melt-

ed by heat, and which, when forced up from —
the mineral regions, has elevated the ftrata at.

the fame time.

4g. Chat granite has undergone achange from) —
a fluid to a folid flate, is evinced from the ery- f
ftallized ftructure in which fome of its compo-

nent

|

/
| i
t

HUTTONIAN THEORY. 85

nent parts are ufually found. This cryftalliza-
tion is particularly to be remarked of the felt-
fpar, and alfo of the fchorl, where there is any
admixture of that fubftance, whether in flender
fpiculz, or in larger maffes. The quartz itfelf

' isin fome cafes cryftallized, and is fo, perhaps,

more frequently than is generally fuppofed.
The fluidity of granite, in fome former period
of its exiftence, is fo evident from this, as to
make it appear fingular that it fhould ever have
been confidered as a foflil that had remained al-
ways the fame, and one, into the origin of which
it was needlefs to inquire. If the regular forms
of cryftallization are not to be received as proofs
of the fubftance to which they belong having
paffed from a fluid to a folid ftate, neither are
the figures of fhells and of other fuppofed petri-
factions, to be taken as indications of a pailage
from the animal to the mineral kingdom; fo
that there is an end of all geological theories,
and of all reafonings concerning the ancient
condition of the globe. To an argument which
ftrikes equally at the root of all theories, it be-
longs not to this, in particular, to make any re-
ply. |

80. We fhall, therefore, confider it as admit-

_ ted, that the materials of the granite were ori-

ginally fluid; and, in addition to this, we think
it can eafily be proved, that this fluidity was
F 3 not

86 ILLUSTRATIONS OF THE

not that of the elements taken feparately, but of
the entire mafs. This lat conclufion follows,
from the ftructure of thofe fpecimens, where
one of the fubftances is impreffed by the forms
which are peculiar to another. Thus, in the
Portfoy granite *, which Dr Hutton has fo mi-
nutely defcribed, the quartz is impreffed by the
rhomboidal cryftals of the feltfpar, and the
ftone thus formed is compaé and highly confo-
lidated. Hence, this granite is not a congeries
of parts, which, after being feparately formed,
were fomehow brought together and agglutina-
ted; but it is certain that the quartz, at leaf,
was fluid when it was moulded on the feltfpar.
In other granites, the impreflions of the fubftan-
ces on one another are obferved ina different
order, and the quartz gives its form to the felt-
{par. This, however, is more unufual; the quartz
is commonly the fubftance which has received
the impreffions of all the reft ; and the fpiculæ of
{chorl often fhoot both acrofs it and the felt{par.
The ingredients of granite were therefore
fluid when mixed, or at leat when in conta@
with one another. Now, this fluidity was not
the effect of folution in a menftruum ; for, in
that cafe, one kind of cryftal ought not to im-
prefs another, but each of them fhould have its

own peculiar fhape.
81. The

* Theory of the Earth, vol. i. P. 104.

HUTTONIAN THEORY. $7

81. The perfe& confolidation of many gra-
nites, furnifhes an argument to the fame effect.
For, agreeably to what was already obferved, in
treating of the ftrata, a fubftance, when cryftal-
lizing, or pafling from a fluid to a folid flate,
cannot be free from porofity, much lets fill up
completely a fpace of a given form, if, at the
fame time, any folvent is feparated from it ; be-
caufe the folvent fo feparated would ftill occupy
a certain fpace, and when removed by evapora-
tion or otherwife, would leave that {pace emp-
ty. The perfect adjuftment, therefore, of the
fhape of one fet of cryfiallizing bodies, to the
fhape of another fet, as in the Portfoy granite,
and their confolidation into one mais, is as
ftrong a proof as could be defired, that they cry-
ftallized from a ftate of fimple fluidity, fuch as,
of all known caufes, heat alone is able to pro-
duce.

82. This conclufion, however, does not reft
on a fingle clafs of facts. It has been obferved
in many inftances, that where granite and ftra-,
tified rocks, fuch as primary {chiftus, are in
contact, the latter are penetrated by veins of the
former, which traverfe them in various direc-
tions. Thefe veins are of different dimenfions,
fome being of the breadth of feveral yards, others
of a few inches, or even tenths of an inch;
they diminifh as they recede from the main bo~

3 F4 dy

$3 ILLUSTRATIONS OF THE

dy of the granite, to which they are always
firmly united, conftituting, indeed, a part of the
fame continued rock. | ,

Thefe phenomena, which were firt diftinaly
obferved by Dr Hutton, are of great importance
in geology, and afford a clear folution of the
two chief gueftions concerning the relation
between granite and fchiftus. As every vein
muft be of a date pofterior to the body in
which it is contained, it follows, that the

{chiftus was not fuper-impofed on the granite, (

after the formation of this laft. If it be argued,
that thefe veins, though pofterior to the {chifti,
are alfo pofterior to the granite, and were form-
ed by the infiltration of water in which the gra-
nite was diffolved or fufpended ; it may be re-
plied, Imo, That the power of water to dif
folve granite, is a poftulatum of the fame kind
that we have fo often, and for fuch good reafon,
refufed to concede; and, 2do, That in many in-
{tances the veins proceed from the main body of
the granite upwards into the {chiftus ; fo that
they are in planes much elevated in refpect of
the horizon, and have a direGion quite oppofite
to that which the hypothefis of infiltration re-

quires. It remains certain, therefore, that the |

whole mafs of granite, and the veins proceeding

from it, are coeval, and both of later formation _

than the ftrata,

Now,

ae

HUTTONIAN THEORY. — 89

Now, this being eftablifhed, and the fluidity

of the veins, when they penetrated into the fchi-

ftus, being obvious, it neceffarily follows, that
the whole granite mafs was alfo fluid at the
fame time. But this can have been brought
about only by fubterraneous heat, which alfo
impelled the melted matter againft the fuper-
incumbent ftrata, with fuch force as to raife them
from their place, and to give them that highly in-

_ clined pofition in which they are fill fupported

by the granite, after its fluidity has ceafed. Thus
a conclufion, rendered probable by the cryftalli-
zation of granite, is eftablifhed beyond all contra-
diction by the phenomena of granitic veins *.

83. With the granite, we fhall confider the
proof of the igneous origin of all mineral fub-
{tances as completed. Thefe fubftances, there-
fore, whether flratified or unftratified, owe their
coniolidation to the fame caufe, though ading
with different degrees of energy. The ftrati-
fied have been in general only foftened or pene-
trated by melted matter, whereas the unftrati-
fied have been reduced into perfect fufion.

84. In this general conclufion we may diftin-
guifh two parts, which, in their degree of cer-

_ tainty, differ perhaps fomewhat from one ano-

ther. The firft of thefe, and that which ftands
higheft in point of evidence, confifts of two
; propofitions ;

* Norte xv.

90 ILLUSTRATIONS OF THE

propofitions ; namely, that the fluidity which
preceded the confolidation of mineral fubftances
Was SIMPLE, that is, it did not arife from the
combination of thefe fubftances with any fol-
vent; and, next, that after confolidation, thefe
bodies have been raifed up by an expanfive
force acting from below, and have by that
means been brought into their prefent fituation.
Thefe two propofitions feem to me to be fup-
ported by all the evidence that is neceflary to
conititute the moft perfect demonttration.

85. The other part of the general conclufion,
that fire, or more properly heat, was the caufe
of the fluidity of thefe mineral bodies, and alfo
ef their fubfequent elevation, is not perhaps to
be confidered as a truth fo fully demonftrated as
the two preceding propofitions ; it is, no doubt,
a matter of THEORY ; or a portion of one of thofe
inyiñble chains by which men feek to connect
in the mind the ftate of nature that is prefent,
with the flates of it that are paft; and partici-
pates of that uncertainty from which our rea-
fonings concerning fuch caufes as are not direé
objects of perception, are hardly ever exempted.
That it participates of this uncertaimty in a ve-
ry flight degree, will, however, be admitted, `
when it is confidered that the caufe affigned has
been proved fuflicient for the effet; that the
fame is not true of any other known caufe ; and

that

—

FE.

=

i

HUTTONIAN THEORY. 9I

that this theory accounts, with fingular fimpli-
city and precifion, for a fyftem of facts fo va-
rious and complex, as that which is prefented
by the natural hiftory of the globe.

86. Neither can it be faid that the exiftence
of fubterraneous. heat is a principle affumed
without any evidence, but that of the geological
facts which it is intended to explain: on the
contrary, it is proved by phenomena within the
circle of ordinary experience, namely, thofe of
hot-{prings, volcanoes, and earthquakes. Thefe
leave no doubt of the exiftence of heat, and of a
moving and expanfive power, in the bowels of
the earth; fo that the only queftions are, at
what depth is this power lodged? to what ex-
tent, and with what intenfity, does it a@? That
it is lodged at a very confiderable depth, is ren-

„dered probable by the permanency of fome of

the preceding phenomena: from the earlieft
times many fountains have retained their heat to
the prefent day ; and volcanoes, though they be-
come extinguifhed at length, have a very long
period allotted for their duration. The caufe of
earthquakes is certainly a force that refides very
deep under the furface, otherwife the extent of
the concufflion could not be fuch as has been ob-
ferved in many inftances.

87. The intenfity of volcanic fire, is another
circumftance that favours the opinion of its be-

ing

92 ILLUSTRATIONS OF THE

ing feated deep under the furface. That this
intenfity is confiderable, is certain from the ex.
periments made by Sir James Hall on the fufi.
bility of whin-ftone and lava; from which jt
appears, that the loweft temperature in which

either of thefe ftones melt, is about 30° of

Wedgewood’s pyrometer. Some mineralogifts
have indeed aflirmed, that lava is melted, not by
the intenfity of the heat applied to it, but in
confequence of a certain combination formed
‘between it and bituminous fubftances, in a man-
ner which they do not attempt to explain, and
which has indeed no analogy to any thing that is
Known. That a hypothefis, formed in fuch di-
rect oppofition to the moft obvious principles of
inductive reafoning, fhould have been imagined
‘by a philofopher who had examined the pheno-
mena of Ætna and Vefuvius with much atten-
tion, and defcribed them with great accuracy
and truth, is more wonderful than that it fhould
have been adopted by mineralogifts, whofe views
of nature may have been confined within a ca-
binet or a laboratory. It is, however, a hy-
pothefis, which, having never had any fupport
but from other hypothefes, hardly merited the
dire refutation that it has received from the
experiments juft mentioned. |

88. But, if the intenfity of volcanic heat be q
fuch as is here ftated, it will be found very —
difficult —

en,

HUTTONIAN THEORY. ~ 93

difficult to account for a fire of fuch activity,
and of fuch long continuance in the fame
{pot, by any decompofition of mineral fubftances
near the furface. In the place where this com-
buftion is fuppofed to exift, it muft be remem-
bered, that there is no frefh fupply of materials
to replace thofe that have been confumed, and
that, therefore, the original accumulation of
thefe materials in one {pot, muft have been very
unlike any thing that has ever been obferved
concerning the difpofition of minerals in the

bowels of the earth. |
89. If, on the other hand; we afcribe the
phenomena of volcanoes to the central heat, the
account that may be given of them is fimple,
and. confiftent with itfelf. According to all the
appearances from which the exiftence of fuch
heat has been inferred above, it is of a nature fo
far different from ordinary fire, that it may re-
quire no circulation of air, and no fupply of
combuftible materials to fupport it. It is not
accompanied with inflammation or combuttion,
the great preflure preventing any feparation of
parts in the fubftances on which it adts, and the
abfence of that elaftic fluid without which heat
feems to have no power to decompofe bodies,
even the moft. combuftible, contributing to the
unalterable nature of all the fubftances in the
mineral regions. There, of confequence, the
only

64 ILLUSTRATIONS OF THE

only effes of heat are fufion and expanfion ‘
and that which forms the nucleus of the globe
may therefore be a fluid mafs, melted, but un.
changed by the aétion of heat.

go. If, from the confines of this nucleus, we
conceive certain fiflures and openings to traverfe
the folid cruft, and to iffue at the furface of the
earth, the vapours afcending through thefe may
in time heat the fides of the tubes through
which they pafs to a vat diftance from the
lower extremities. It is, indeed, difficult to fix
the limit to which this diftance may extend, on
account of the great difference between the rate
at which heat moves when it has a fluid for its
vehicle, and when it is left to make its way
alone through a folid body. In the prefent cafe,
the fupply of heat is rapid, as being made by a
vapour afcending through a tube of folid rock;
and the diffipation of it flow, as arifing from its

tranfmiffion through the rock. The wafte of

heat is therefore f{mall, compared with the fup-
ply, and grows fmaller at every given point, the
longer the ftream of heated vapour has conti-
nued to flow. Such a ftream, therefore, though

it may at firt be condenfed within a fmall di-
ftance of its fource, will in time reach higher -

and higher, and may at laft be able to carry its
heat to an immenfe diftance from the place of
its original derivation. Thus, it is ealy to con-

_ ceive,

na
e

HUTTONIAN THEORY. 95

ceive, that vapours from the mineral regions

may convey their heat to refervoirs of water

near the furface of the earth, and may in that
manner produce hot fprings, and even boiling
fountains, like thofe of Rycum and Geyfer.

91. When, inftead of a heated vapour, melt-

ed matter is thrown up through the /Aafts or

tubes, which thus communicate with the mi-
neral regions, veins of whinftone and _ bafal-
tes are formed in the interior of the earth.
When the melted matter reaches to the fur-
face, itis thrown out in the form of lava, and
all the other phenomena of volcanoes are produ-
ced. |

Laftly, Where melted matter of this kind, or
vapours without being condenfed, have their
progrefs obftruGted, thofe dreadful concuflions

are produced, which feem to threaten the exift-

ence even of the earth itfelf. ‘Though terrible,
therefore, to the prefent inhabitants of the
globe, the earthquake has its place in the great
fyftem of geological operations, and is part of a
feries of events, effential, as will more clearly ap-
pear hereafter, to the general order, and to the

prefervation of the whole.
such, according to this theory, are the chan- .
ges which have befallen mineral fubftances in
the bowels of the earth; and though different
for the ftratified and unftratified parts of thofe
fubftances,

96 ILLUSTRATIONS OF THE

fubftances, they are conne@ed together by the
fame principle, or explained by the fame caufe,
It remains to confider that part of the hiftory of
both which defcribes their changes after their
elevation to the furface; and here we fhall find
new caules introduced, which are more dire@ly |
the fubjects of obfervation, than thofe hitherto
treated of ; caufes, alfo, which aQ@ on all fofiils
alike, and alike prepare them for their ultimate
deftination.

SEG

HUTTONIAN THEORY. 97

SECTION IIL

OF THE PHENOMENA COMMON TO STRATIFIED
AND UNSTRATIFIED BODIES.

92. HE feries of changes which foflil bodies
are deftined to undergo, does not ceafe
with their elevation above the level of the fea ; it
affumes, however, a new direction, and from the
moment that they are raifed up to the furface,
is conitantly exerted in reducing them again
under the dominion of the ocean. The folidity
is now deftroyed which was acquired in the
bowels of the earth; and as the bottom of the
fea is the great laboratory, where loofe mate-
rials are mineralized and formed into ftone, the
atmofphere is the region where ftones are de-
compofed, and again refolved into earth.
This decompofition of all mineral fubftances,

| expofed to the air, is continual, and is brought

about by a multitude of agents, both chemical
and mechanical, of which fome are known to us,.
and many, no doubt, remain to be difcovered. A-
mong the various aériform fluid- which compofe
our atmofphere, one is already diftinguifhed as.
the grand principle of mineral decompofition ;
the others are not inadtive, and to them we muff
add:

98 ILLUSTRATIONS OF THE

add moifture, heat, and perhaps light; fub-
{tances which, from their affinities to the ele-
ments of mineral bodies, have a power of enter-
ing into combination with them, and of thus di-
minifhing the forces by which they are united
to one another. By the action of air and moi-
fture, the metallic particles, particularly the
iron, which enters in fuch abundance into the
compofition of almoft all foffils, becomes oxy-
dated in fuch a degree as to lofe its tenacity ; fo
that the texture of the furface is deftroyed, and
a part of the body refolved into earth.

93. Some earths, again, fuch as the calcare-
ous, ate immediately diffolved by water; and
though the quantity fo diffolved be extremely

fmall, the operation, by being continually re-

newed, produces a flow but perpetual corrofion,
by which the greateft rocks muft in time be fub-
dued. The action of water in deftroying hard
bodies into which it has obtained entrance, is
much affifted by the viciflitudes of heat and
cold, efpecially when the latter extends as far as
the point of congelation ; for the water, when
frozen, occupies a greater {pace than before, and
if the body is compact enough to refufe room
for this expanfion, its parts are torn afunder by

a repulfive force acting in every diredtion.
94. Befides thefe caufes of mineral decompo-
fition, the action of which we can in fome mea-
furç

idiss

=

HUTTONIAN THEORY. 99

fure trace, there are others known to us only by
their effets.

We fee, for inftance, the pureft rock cryftal
affected by expofure to the weather, its luftre
tarnifhed, and the polifh of its furface impaired,
but we know nothing of the power by which
thefe operations are performed. Thus alfo, in
the precautions which the mineralogift takes to
preferve the frefh fracture of his fpecimens, we
have a proof how indifcriminately all the pro-
ductions of the foffil. kingdom are expofed to
the attacks of their unknown enemies, and we
perceive how difficult it is to delay the begin-
nings of a procefs which no power whatever
can finally countera&.

95. The mechanical forces employed in the
difintegration of mineral fubftances, are more
eafily marked than the chemical. Here again
water appears as the moft active enemy of hard
and folid bodies; and, in every ftate, from
tranfparent vapour to folid ice, from the {mallet
rill to the greateft river, it attacks whatever has
emerged above the level of the fea, and labours
inceffantly to reftore it to the deep. , The parts
loofened and difengaged by the chemical agents,
are carried down by the rains, and, in their de-
icent, rub and grind the fuperficies of other bo-
dies. Thus water, though incapable of acting
on hard fubitances by dire@ attrition, is the

G2 caule

LOO ILLUSTRATIONS OF THE

caufe of their being fo ated on; and, when it
defcends in torrents, carrying with it fand, gra-
vel, and fragments of rock, it may be truly faid
to turn the forces of the mineral kingdom againgt
itfelf, Every feparation which it makes is ne-
ceflarily permanent, and the parts once detach-
ed can never be united, fave at the bottom of
the ocean. | ie
: 96. But it would far exceed the limits of this
fketch, to purfue the caufes of mineral decom-
pofition through all their forms. It is fufficient
to remark, that the confequence of fo many mi-
nute, but indefatigable agents, all working toge-
ther, and having gravity in their favour, is a fyf-
tem of univerfal decay and degradation, which
may be traced over the whole furface of the land,
from the mountain top to the fea fhore. That we
may perceive the full evidence of this truth, one
of the moft important in the natural hiftory of the
globe, we will begin our furvey from the latter
of thefe ftations, and retire gradually toward the
former. | : |
97. If the coat is bold and rocky, it fpeaks
a language eafy to be interpreted, Its broken
and abrupt contour, the deep gulphs and falient
promontories by which it is indented, and the pro-
portion which thefe irregularities bear to the force
of the waves, combined with the inequality of
hardnefs in the rocks, prove, that the prefent
- line

a a —— ae
i x . n aii t p

O Cin

HUTTONIAN THEORY. IOI

line of the fhore has been determined by the
action of the fea. The naked and precipitous
cliffs which overhang the deep, the rocks hollow-
ed, perforated, as they are farther advanced in
the fea, and at lat infulated, lead to the fame
conclufion, and mark very clearly fo many dif-
ferent ftages of decay. It is true, we do not fee
the fucceflive fteps of this progrefs exemplified
in the ftates of the fame individual rock, but
we fee them clearly in different individuals ; and
the conviction thus produced, when the pheno-
mena are fufficiently multiplied and varied, is
as irrefiftible, as if we faw the changes actually
effected in the moment of obfervation.

On fuch fhores, the fragments of rock once
detached, become inftruments of further de-
firuction, and make a part of the powerful
artillery with which the ocean affails the bul-
warks of the land: they are impelled againft
the rocks, from which they break off other frag-
ments, and the whole are thus ground againft
one another ; whatever be their hardnefs, they
are reduced to gravel, the fmooth furface and
round figure of which, are the moft certain
proofs of a detritus which nothing can refift.

98. Again, where the fea-coaft is flat, we have
abundant evidence of the degradation of the
land in the beaches of fand and fmall gravel;
the fand banks and fhoals that are continually .

G3 changing 5

102 ILLUSTRATIONS OF THE

changing ; the alluvial land at the mouths of the
rivers; the bars that feem to oppofe their dif.
charge into the fea, and the fhallownefs of the
fea itfelf On fuch coafts, the land ufually
feems to gain upon the fea, whereas, on fhores
of a bolder afpect, it is the fea that generally
appears to gain upon the land. What the land
acquires in extent, however, it lofes in eleva-
tion; and, whether its furface increafe or di-
miniifh, the depredations made on it are in both
cafes evinced with equal certainty.

99. If we proceed in our furvey from the
fhores, inland, we meet at every ftep with the
fulleft evidence of the fame truths, and parti-
cularly in the nature and economy of rivers.
Every river appears to confift of a main trunk,
fed from a variety of branches, each running in
a valley proportioned to its fize, and all of them
together forming a fyftem of vallies, communi-
cating with one another, and having fuch a nice
adjuftment of their declivities, that none of
them join the principal valley, either on too
high or too low a level; a circumftance which
would be infinitely improbable, if each of thefe
vallies were not the work of the ream that
flows in it.

If indeed a river confifted of a fingle ftream,
without branches, running in a ftraight val-
ley, it might be fuppofed that fome great con-

cuffion,

HUTTONIAN THEORY. 103

cuffion, or fome powerful torrent, had open-

ed at once the channel by which its waters

äre conducted to the ocean; but, when the
ufual form of a river is confidered, the trunk
divided into many branches, which rife at a
great diftance from one another, and thefe again
fubdivided into an infinity of fmaller ramifica-
tions, it becomes ftrongly imprefled upon the
mind, that all thefe channels have been cut by
the waters themfelves; that they have been
flowly dug out by the wafhing and erofion of
the land; and that it is by the repeated touch-
es of the fame inftrument, that this curious
affemblage of lines has been engraved fo deeply
on the furface of the globe.

too. The changes which have taken place in
the courfes of rivers, are alfo to be traced, in ma-
ny inftances, by fucceflive platforms of flat al-

_luvial land, rifing one above another, and mark-
ing the different levels on which the river has

run at different periods of time. Of thefe, the
number to be diftinguifhed, in fome inftances,
is not lefs than four, or even five; and this ne-
eeffarily carries us back, like all the operations
we are now treating of, to an antiquity ex-
tremely remote: for, if it be confidered, that
each change which the river makes in its bed,
obliterates at leaft a part of the monuments of
former changes, we fhall be convinced, that

G4 only

104 ILLUSTRATIONS OF THE

only a {mall part of the progreffion can leave
any diftinct memorial behind it, and that there
is no reafon to think, that, in the part which -
we fee, the beginning is included *.

101. In the fame manner, when a river under.
mines its banks, it often difcovers depofites of
fand and gravel, that have been made when it
ran ona higher level than it does at prefent,
In other inftances, the fame ftrata are’ feen on
both the banks, though the bed of the river is
now funk deep between them, and perhaps
holds as winding a courfe through the folid
rock, as if it flowed along the furface; a proof
that it muft have begun to fink its bed, when it
ran through fuch loofe materials as oppofed but
a very inconfiderable refiftance to its ftream.
A river, of which the courfe is both ferpentine
and deeply excavated in the rock, is among the
phenomena, by which the flow wafte of the
land, and alfo the caufe of that wafte, are moft
direCtly pointed out.

102. Itis, however, where rivers ifue through
narrow defiles among mountains, that the iden-
tity of the ftrata on both fides is moft eafily re-
cognifed, and remarked at the fame time with
the greateft wonder. On obferving the Pa-
towmack, where it penetrates the ridge of the
Allegany mountains, or the Irtifh, as it iffues
from the defiles of Altai, there is no man, how-

ever
* NOTE xvi,

—-

HUTTONIAN THEORY. 103

ever little addicted to geological fpeculations,
who does not immediately acknowledge, that
the mountain was once continued quite acrofs
the {pace in which the river now flows ; and, if
he ventures to reafon concerning the caufe of
fo wonderful a change, ‘he afcribes it to fome
great convulfion of nature, which has torn the
mountain afunder, and opened a pafiage for the

, waters. It is only the philofopher, who has

deeply meditated on the effe&s which action
long continued is able to produce, and on the
fimplicity of the means which nature employs
in all her operations, who fees in this nothing
but the gradual working of a ftream, that once
flowed as high as the top of the ridge which it
now fo deeply interfeds, and has cut its courfe
through the rock, in the fame way, and almoft
with the fame inftrument, by which the lapi-
dary divides a block of marble or granite.

103. It is highly interefting to trace up, in

_ this manner, the aGion of caufes with which

we are familiar, to the produ@ion of effects,
which at firft feem to require the introdu@ion
of unknown and extraordinary powers; and it
is no lefs interefting to obferve, how {fkilfully
nature has balanced the a&tion of all the minute
caufes of wafte, and rendered them conducive
meine general good. Of this we have a
moft remarkable inftance, in the provifion
made for preferving the foil, or the coat of ve-

getable

106 ILLUSTRATIONS OF THE

getable mould, fpread out over the furface of
the earth. This coat, as it confifts of loofe ma
. terials, is eafily wafhed away by the rains, and
is continually carried down by the rivers into
the fea. This effect is vifible to every one;
the earth is removed not only in the form of
fand and gravel, but its finer particles fufpend.
ed in the waters, tinge thofe of fome rivers con.
tinually, and thofe of all occafionally, that is,
when they are flooded or fwollen with rains,
The quantity of earth thus carried down, varies
according to circumftances ; it has been compu-
ted, in fome inftances, that the water of a ri-
ver in a flood, contains earthy matter fufpended
in it, amounting to more than the two hun-
dred and fiftieth part of its own bulk *. The
foil, therefore, is continually diminithed, its
parts being tranfported from higher to lower
levels, and finally delivered into the fea. But
it is a fact, that the foil, notwithftanding, re-
mains the fame in quantity, or at leaft nearly
the fame, and muft have done fo, ever fince the
earth was the receptacle of animal or vegetable
life. The foil, therefore, is augmented from
other caufes, juft as much, at an average, as it
is diminifhed by that now mentioned ; and this
augmentation evidently can proceed from no-

thing

* See Lehman, Traités de Phyf. &c. tom. ili. p. 35%
Note.

bal acta

q -HUTTONIAN THEORY. 107

ty thing but the conftant and flow difintegration of
the rocks. In the permanence, therefore, of a coat
of vegetable mould on the furface of the earth,
we have a demontftrative proof of the continual
deftruction of the rocks; and cannot but ad-
mire the fkill, with which the powers of the
many chemical and mechanical agents employ-
_ ed in this complicated work, are fo adjufted,
ty as to make the fupply and the wafte of the foil
MN exactly equal to one another.

i 104. Before we take leave of the rivers and
p = the plains, we muft remark another fact, often
1 obferved in the natural hiftory of the latter, and
k clearly evincing the former exiftence of immenfe
lt bodies of frata, in fituations from which they
Ik have now entirely difappeared. The fa& here
i alluded to is, the great quantity of round and
hard gravel, often to be met with in the foil,
i under fuch circumftances, as prove, that it can
t only have come from the decompofition of rocks,
| that once occupied the very ground over which
i this gravel is now fpread. In the chalk coun-
try, for inftance, about London, the quantity of
flints in the foil is every where great ; and, in
Į particular fituations, nothing but flinty gravel
j is found to a confiderable depth. Now, the
» {ource from which thefe flints are derived is
í quite evident, for they are precifely the fame
with thofe contained in the chalk beds, where-
4 | ever

=
a ae

a E o
a - ~

x08 ILLUSTRATIONS OF THE

ever thefe laft are found undifturbed, and from
the deftruction of fuch beds they have no doubt
originated. Hence a great thicknefs of chalk
muft have been decompofed, to yield the quan.
tity of flints now im the foil of thefe countries;
for the flints are but thinly fceattered through
the native chalk, compared with their abun-
dance in the loofe earth. To afford, for ex.
ample, fuch a body of flinty gravel as is found
about Kenfington, what an enormous quantity
of chalk rock muft have been deftroyed? -

105. This argument, which Dr Hutton has
applied particularly to the chalk countries,
may be extended to many others. The great
plain of Crau, near the mouth of the Rhone, is
well known, and was regarded with wonder,
even in ages when the natural hiftory of the
globe was not an object of much attention. The
immenfe quantity of large round gravel-ftones,
with which this extenfive plain is entirely co-
vered, has been fuppofed, by fome mineralo-
gifts, to have been brought down by the Du-
rance, and other torrents, from the Alps; but,
on further examination, has been found to be of
the fame kind that is contained in certain hori-
zontal layers of pudding-ftone, which are the ba-
fis of the whole plain. It cannot be doubted,
therefore, that the vaft body of gravel fpread
over it, has originated from the deftru@ion of

layers

HUTTONIAN THEORY. 109

by layers of the fame rock, which may perhaps have

My rifen to a great height above what is now the

My = furface. Indeed, from knowing the depth of

iw the gravel that covers the plain, and the average

tig quantity of the like gravel contained in a given
wj thicknefs of rock, one might eftimate how much
iy of the latter has been a@ually worn away.
tq Whether data precife enough could be found,

w to give any weight to fuch a computation, muft

ny be left for future inquiry to determine *.

106. In thefe inftances, chalk and pudding-
ftone, by containing in them parts infinitely lefs
deftrudtible than their general mafs, have, after
they are worn away, left behind them very une-
quivocal marks of their exiftence. The fame
has happened in the cafe of mineral veins, where
the fubftances leat fubje& to diffolution have

- remained, and are fcattered at a great diftance
from their native place. Thus gold, the leaft
liable to decompofition of all the metals, is
very generally diffufed through the earth, and
is found, in a greater or lefs abundance, in the
fand of almoft all rivers. But the native place
of this mineral is the folid rock, or the veins
and cavities contained in the rock, and from
thence it muft have made its way into the foil.
This, therefore, is another proof of the vaft ex-
tent to which the degradation of the land, and of

the

a7.
'— aa

* Nove xvii.

IIO ILLUSTRATIONS OF THE

the rock, which is the bafis of it, has been car.
ried; and confequently, of the great difference
between the elevation and fhape of the earth’,
furface in the prefent, and in former ages.

107. The veins of tin furnifh an argument of
the fame kind. The ores of this metal are very
indeftructible, and little fubje& to decompofi-
tion, fo that they remain very long in the ground
without change. Where there are tin veins, as
in Cornwall, the tin-ftone or tin-ore is found in
great abundance in fuch vallies and ftreams
as have the fame direction with the veins;
and hence the /freaming, as it is called, or
wathing of the earth, to obtain the tin-ftone
from it. Now, if it be confidered, that none of
this ore can have come into the foil but from
parts of a vein actually deftroyed, it muf ap-
pear evident that a great wafte of thefe veins has

taken place, and confequently of the {chiftus or

granite in which they are contained.

108. Thefe leffons, which the geologift is
taught in flat and open countries, become more
ftriking, by the fludy of thofe Alpine trads,

where the furface of the earth attains its great-

eft elevation. If we fuppofe him placed for
the firt time in the midft of fach a fcene, as
foon as he has recovered from the impreffion
made by the novelty and magnificence of the
{pectacle before him, he begins to difcover the

footfteps

=

pe ee ee eee ee ee

| HUTTONIAN THEORY. I

footiteps of time, and to perceive, that the works
y of nature, ufually deemed the moft permanent,
are thofe on which the characters of viciffitude
are moft deeply imprinted. He fees himfelf in
the midft of a vaft ruin, where the precipices
ME which rife on all fides with fach boldnefs and af-
I perity, the fharp peaks of the granite mountains,
ot and the huge fragments Da furround their
ME bafes, do but mark fo many epochs in the pro-
wf grefsof decay, and point out the energy of thofe
Cay deitructive caufes, which even the magnitude
wy and folidity of fuch great bodies have been un-
Je able to refift.
fe 109. The refult of a more minute invettiga-
tj tion, is in perfect unifon with this general im-
i preflion. Whence is it, that the elevation of
4 mountains is fo obvioufly conne@ed with the
si hardnefs and indeftru@ibility of the rocks which
pi compofe them? Why is it, that a lofty moun-
tain of foft and fecondary rock is no where to
_ be found; and that fuch chains, as the Pyrenees
or the Alps, never confift of any but the hardeft
fione, of granite for inftance, or of thofe prima-
rary ftrata, which, if we are to credit the pre-
ceding theory, have been twice heated in the
fires, and twice tempered in the waters, of the
mineral regions? Is it not plain that this arifes,
not from any direct connection between the
hardnefs of Hones, and their height in the at-
mofphere,

ziz ILLUSTRATIONS OF THE

mofphere, but from this, that the wafte and da
tritus to which all things are fubje@, will not
allow foft and weak fubftances to remain long
in an expofed and elevated fituation? Were it
not for this, the fecondary rocks, being in pofi.
tion fuperincumbent on the primary, ought to
be the higheft of the two, and fhould cover the
primary, (as they no doubt have at one time
done), in the higheft as well as the loweft fitua-
tions, or among the mountains as well as in the
plains.

110. Again, wherefore is it, that among all
mountains, remarkable for their ruggednefs and
afperity, the rock, on examination, is always
found of very unequal deftructibility, fome parts
yielding to the weather, and to the other caules
of difintegration, much more flowly than the
reft, and having ftrength fufficient to iupport
themfelves, when left alone, in flender pyramids,
bold projeCtions, and overhanging cliffs ? Where,
on the other hand, the rock waftes uniformly,
the mountains are fimilar to one another; their
{wells and flopes are gentle, and they are bound-
ed by a waving and continuous furface. The
intermediate degrees of refiftance which the
rocks oppofe to the caufes of deftruction, produce
intermediate forms. It is this which gives to
the mountains, of every different fpecies of rock,

a

reeni

HUTTONIAN THEORY. 113

a different habit and expreflion, and which, in
particular, has imparted to thofe of granite that
venerable and majeftic character, by which they
rarely fail to be diftinguifhed.

111. The ftructure of the vallies among
mountains, (hews clearly to what caufe their
exiftence is to be afcribed. Here we have firt
a large valley, communicating dire@ly with the
plain, and winding between high ridges of
mountains, while the river in the bottom of it
defcends over a furface, remarkable, in fuch a
{cene, for its uniform declivity. Into this, open
a multitude of tranfverfe or fecondary vallies,
interfecting the ridges on either fide of the for-

mer, each bringing a contribution to the main 3

ftream, proportioned to its magnitude; and, ex-
cept where a catara now and then intervenes,
all having that nice adjuftment in their levels,
(99.) which is the more wonderful, the greater

the irregularity of the furface. Thefe fecon-

dary vallies have others of a fmaller fize open-
ing into them; and, among mountains of the
firft order, where all is laid out on the greatett
fcale, thefe ramifications are continued to a

fourth, and even a fifth, each diminifhing in

fize as it increafes in elevation, and as its fup-
ply of water is lefs. T hrough them all, this law
is in general obferved, that where a higher val-
ley joins a lower one, of the two angles which

it

II4 ILLUSTRATIONS OF THE

it makes with the latter, that which is obtufe |

is always on the defcending fide ; a law that is
the fame with that which regulates the con-
fluence of ftreams running on a furface nearly
of uniform inclination. This alone is a proof
that the vallies are the work of the ftreams;
and indeed what elfe but the water itfelf, work-

ing its way through obftacles of unequal refift. .
ance, could have opened or kept up a commu-

nication between the inequalities of an irregular
and alpine furface.

112. Many more arguments, all leading to
the fame conclufion, may be deduced from the
general facts, known in the natural hiftory of
mountains ; and, if the Oreologift would trace
back the progrefs of wafe, till he come in fight of
that original firuCture, of which the remains are
ftill fo vaft, he perceives an immenfe mafs of folid
rock, naked and unfhapely, as it firt emerged
from the deep, and incomparably greater than
all that is now before him. The operation of
tains and torrents, modified by the hardnefs and

tenacity of the rock, has worked the whole into -

its prefent form; has hollowed out the vallies,

and gradually detached the mountains from the |

general mais, cutting down their fides into fteep
precipices at one place, and {moothing them in-
to gentle declivities at another. From this has
refulted a tranfportation of materials, which, both

for

—_—, e o> 3s

t HUTTONIAN THEORY. ZIG
at, for the quantity of the whole, and the magni-
% tude of the individual fragments, muft feem in-
tj credible to every one, who has not learned to
Dy calculate the effects of continued action, and to
wq refle&, that length of time can convert acciden-
ij talinto fteady caufes. Hence fragments of rock,
eil from the central chain, are found to have tra-

m ç Velled into diftant vallies, even where many in-
~ ferior ridges intervene: hence the granite of
Mount Blanc is feen in the plains of Lombardy,
or on the fides of Jura; and the ruins of the
Carpathian mountains lie fcattered over the
fhores of the Baltie *.

113. Thus, with Dr Hutton, we mhall be dif. -
pofed to confider thofe great chains of moun-
tains, which traverfe the furface of the globe,
as cut out of maffes vaftly greater, and more
lofty than any thing that now remains. The
prefent appearances afford no data for calcula-
ting the original magnitude of thefe maffes, or
the height to which they may have been ele-
vated. The neareft eftimate we can form is,
where a chain or group of mountains, like thofe
of Rofa in the Alps, is horizontally ftratified,
and where, of confequence, the undifturbed po-
fition of the mineral beds enables us to refer

_ the whole of the prefent inequalities of the fur-
face to the operation of wafte or decay. Thefe

H2 mountains,
z Nove xvin.

i16 ILLUSTRATIONS OF THE

mountains, as they now ftand, may not inapt.
ly be compared to the pillars of earth which
workmen leave behind them, to afford a mea-
fure of the whole quantity of earth which they
have removed. As the pillars, (confidering the
mountains as fuch), are in this cafe of lefs height
than they originally were, fo the meafure fur-
nifhed by them is but a limit, which the quan-
tity fought muft neceflarily exceed.

114. Such, according to Dr Hutton’s theory,
are the changes which the daily operations of
wafte have produced on the furface of the globe.
Thefe operations, inconfiderable if taken fepa-
rately, become great, by confpiring all to the
fame end, never counteracting one another, but
proceeding, through a period of indefinite ex-
tent, continually in the fame direction. Thus
every thing defcends, nothing returns upward ;
the hard and folid bodies every where diffolve,
and the loofe and foft no where confolidate.
The powers which tend to preferve, and thofe
which tend to change the condition of the earth’s
furface, are never im equilibrio ; the latter are,
in all cafes, the moft powerful, and, in refpect
of the former, are like living in comparifon of
dead forces. Hence the law of decay is one
which fuffers no exception: The elements of all
bodies were once loofe and unconnected, and to

the

Lm,

HUTTONIAN THEORY. 117

by the fame ftate nature has appointed that they
ly = fhould all return.

the. 115. It affords no prefumption againft the
th reality of this progrefs, that, in refpe@ of man,
gh it is too flow to be immediately perceived: The
fy utmoft portion of it to which our experience can

extend, is evanefcent, in comparifon with the
whole, and muft be regarded as the momentary
increment of a vaft progreffion, circum{cribed
by no other limits than the duration of the
world. Tıme performs the office of integrating
the infinitefimal parts of which this progreffion
is made up; it collects them into one fum, and
produces from them an amount greater than any
that can be afiigned.

116. While on the furface of the earth fo
much is every where going to decay, no new
production of mineral fubftances is found in any
region acceflible to man. ‘The inftances of what
are called petrifactions, or the formation of fto-
ny fubftances by means of water, which we.
fometimes obferve, whether they be ferruginous
concretions, or calcareous, or, as happens in fome
rare cafes, filiceous ftalatites, are too few in
number, and too inconfiderable in extent, to be.
deemed material exceptions to this general rule.
The bodies thus generated, alfo, are no fooner
formed, than they become fubject to wafte and.
diffolution, like all the other hard fubftances in

H 3 nature 3.

r15 ILLUSTRATIONS OF THE

nature; fo that they but retard for a while the
progrefs by which they are all refolved into duft,
and fooner or later committed to the bofom of
the deep. ;
117. We are not, however, to imagine, that
there is no where any means of repairing this
walte; for, on comparing the conclufion at
which we are now arrived, viz. that the prefent
continents are all going to decay, and their ma-
terials defcending into the ocean, with the pro-
pofition firt laid down, that thefe fame conti-
nents are compofed of materials which muft have
been collected from the decay of former rocks,
it is impoflible not to recognife two corre-
{ponding fteps of the fame progrefs; of a pro-
grefs, by which mineral fubftances are fubje&ed
to the fame feries of changes, and alternately
wafted away and renovated. In the fame man-
ner, as the prefent mineral fubftances derive
their origin from fubftances fimilar to them-
felves; fo, from the land now going to decay,
the fand and gravel forming on the fea-fhore, or
in the beds of rivers; from the {hells and corals
which in fuch enormous quantities are every day
accumulated in the bofom of the fea; from
the drift wood, and the multitude of vegetable
and animal remains continually depofited in the
ocean: from all thefe we cannot doubt, that
firata are now forming in thofe regions, to
| which

ee

| HUTTONIAN THEORY. 119

which nature feems to have confined the powers
of mineral reproduction; from which, after
being confolidated, they are again deftined to
emerge, and to exhibit a feries of changes fimi-
lar to the paf *.

118. How often thefe viciflitudes of decay
and renovation have been repeated, is not for
us to determine: they conftitute a feries, of
which, as the author of this theory has remark-
ed, we neither fee the beginning nor the end ;
a circumftance that accords well with what is
known concerning other parts of the economy
of the world. In the continuation of the dif-
ferent fpecies of animals and vegetables that in-
habit the earth, we difcern neither a beginning
nor an end; and, in the planetary motions,
where geometry has carried the eye fo far both
into the future and the paft, we difcover no
mark, either of the commencement or the ter-
mination of the prefent order}. It is unreafon-
able, indeed, to fuppofe, that fuch marks fhould
any where exift. The Author of nature has not
given laws to the univerfe, which, like the infti-
tutions of men, carry in themfelves the elements
of their own deftruction. He has not permit-
ted, in his works, any fymptom of infancy or of
old age, or any fign by which we may eftimate
either their future or their paft duration. He
may put anend, as he no doubt gave a begin-

Hg ning,
* NOTE xIx. + NOTE xx. 3

120 ILLUSTRATIONS OF THE

ning, to the prefent fyftem, at fome determinate
period; but we may fafely conclude, that this
great caiaftrophe will not be brought about by
any of the laws now exifting, and that it is not
indicated by any thing which we perceive.
119. To affert, therefore, that, in the econo-
my of the world, we fee no mark, either of 4
beginning or an end, is very different from af.
firming, that the world had no beginning, and
will have no end. The firft is a conclufion jut.
tified by common fenfe, as well as found phi-
lofophy ; while the fecond is a prefumptuous and
unwarrantable affertion, for which no reafon
from experience or analogy can ever be afligned,

Dr Hutton might, therefore, juftly complain

of the uncandid criticifm, which, by fubftitu-
ting the one of thefe affertions for the other, en-
deavoured to load his theory with the reproach

of atheifm and impiety. Mr Kirwan, in bring-

ing forward this harth and ill-founded cen{ure,
was neither animated by the {pirit, nor guided
_ by the maxims of true philofophy. By the fpi-
rit of philofophy, he muft have been induced
to refle&, that fuch poifoned weapons as he was
preparing to ufe, are hardly ever allowable
in {cientific conteft, as having a lefs dire& ten-
dency to overthrow the fyftem, than to hurt the
perfon of an adverfary, and to wound, perhaps
incurably, his mind, his reputation, or his peace.

By

ie a E o ey eel a peT r

dba a ae eer

HUTTONIAN THEORY. IZI

By the maxims of philofophy, he muft have
3 been reminded, that, in no part of the hiftory
= of nature, has any mark been difcovered, either
of the beginning or the end of the prefent or-
der ; and that the geologift fadly miftakes, both
the object of his fcience and the limits of his un-
derftanding, who thinks it his bufinefs to explain
the means employed by INFINITE WISDOM for
eftablifhing the laws, which now govern the
i world.
ti By attending to thefe obvious confiderations,
al Mr Kirwan would have avoided a very illiberal
a and ungenerous proceeding ; and, however he
might have differed from Dr Hutton as to the
truth of his opinions, he would not have cen-
fured their tendency with fuch rath and unjufti-
fiable feverity.

But, if this author may be blamed for want-
ing the temper, or neglecting the rules, of phi-
lofophic inveftigation, he is hardly lefs culpa-
ble, for having fo flightly confidered the fcope
and fpirit of a work which he condemned fo
freely, In that work, inftead of finding the
world reprefented as the refult of neceffity
or chance, which might be looked for, if the
accufations of atheifm or impiety were well
founded, we fee every where the utmoft atten-
tion to difcover, and the utmoft difpofition to
admire, the inftances of wife and beneficent de-

fign,

122 ILLUSTRATIONS OF THE

fign manifefted in the ftruture, or economy of
the world. ‘The enlarged views of thefe, which

his geological fyftem afforded, appeared to Dr

Hutton himfelf as its moft valuable refult. They
were the parts of it which he contemplated
with greateft delight; and he would have been
lefs flattered, by being told of the ingenuity and
originality of his theory, than of the addition
which it had made to our knowledge of final
caufes. It was natural, therefore, that he fhould
be hurt by an attempt to accufe him of apinions,
fo different from thofe which he had always
taught; and if he anfwered Mr Kirwan’s attack
with warmth or afperity, we mutt afcribe it to the
indignation excited by unmerited reproach. _
120. But to return to the natural hiftory of the
earth : Though there be in it no data, from which
the commencement of the prefent order can be
a{certained, there are many by which the exift-
ence of that order may be traced back to an anti-
quity extremely remote... The beds of primitive
‘{chiftus, for inftance, contain fand, gravel, and
other materials, collected, as already fhewn, from

the diffolution of mineral bodies; which bodies, /
therefore, muft have exifted long before the oldeft
part of the prefent land was formed. Again, in —

this gravel we fometimes find pieces of fandftone,
and cf other compound rocks, by which we are of
courfe carried back a ftep farther, fo as to reach

a

z r

m A:

HUTTONIAN THEORY. 123

i, = 3 fyftem of things, from which the prefent is
to) the third in fucceffion ; and this may be confi-
Th dered as the moft ancient epocha, of which any
memorial exifts in the records of the foflil
hy kingdom.

ke 121. Next in the order of time to the confo-
lidation of the primary ftrata, we muft place
their elevation, when, from being horizontal,
h and at the bottom of the fea, they were broken,
fet on edge, and raifed to the furface. Itis even
probable, as formerly obferved, that to this fuc-
ceeded a depreflion of the fame ftrata, and a fe-
lit cond elevation, fo that they have twice vifited
ii the fuperior, and twice the inferior regions.
During the fecond immerfion, were formed, firk,
i the great bodies of pudding-ftone, that in fo

ls many inftances lie immediately above them;
i and next were depofited the ftrata that arẹ
I` ftri&ly denominated fecondary.

w. 122. The third great event, was the raifing

up of this compound body of old and new ftra-
ta from the bottom of the fea, and forming it
into the dry land, or the continents, as they now
exift*. Contemporary with this, we muft fup-
pofe the injeCtion of melted matter among the
frata, and the confequent formation of the cry-
ftallized and unftratified rocks, namely, the gra-
nite, metallic veins, and veins of porphyry and

whinftone.

y Note XXI,

rd

124 ILLUSTRATIONS OF THE

whinftone. This, however, is to be confidered
as embracing a period of great duration; and
it muft always be recollected, that veins are
found of very different formation ; fo that when
we {peak generally, it is perhaps impoffible to
ftate any thing more precife concerning their an-
tiquity, than that they are pofterior to the ftrata,
and that the veins of whinftone feem to be the
moft recent of all, as they traverfe every other,
123. In the fourth place, with refpe& to
time, we mutt clafs the facts that regard the de-
tritus and wafte of the land, and muft carefully
diftinguifh them from the more ancient pheno-
mena of the mineral kingdom. Here we are
to reckon the fhaping of all the prefent inequa-
lities of the furface; the formation of hills of
gravel, and of what have been called tertiary ftra-
ta, confifting of loofe and unconfolidated mate-
rials ; alfo collections of fhells not mineralized,
like thofe in Turaine; fuch petrifactions as
thofe contained in the rock of Gibraltar, on the
coaft of Dalmatia, and in the caves of Bayreuth.
The bones of land animals found in the foil,

fuch as thofe of Siberia, or North America, are 3

probably more recent than any of the former *.
124. Thefe phenomena, then, are all fo many
marks of the lapfe of time, among which the
principles of geology enable us to diftinguith a
certain
* NOTE xxiL

Fa all

HUTTONIAN THEORY. 12

ty certain order, fo that we know fome of them to
A be more, and others to be lefs diftant, but with-
h, out being able to afcertain, with any exactnefs,
th the proportion of the immenfe intervals which
bh feparate them. Thefe intervals admit of no
it, comparifon with the aftronomical meafures of
ly time; they cannot be expreffed by the revolu-
yj tions of the fun or of the moon; nor is there
fy any fynchronifm between the mof recent epo-
a, chas of the mineral kingdom, and the moft an-
nj cient of our ordinary chronology.
i 125. On what is now faid is grounded ano-
ther objection to Dr Hutton’s theory, namely,
that the high antiquity afcribed by it to the
earth, is inconfiftent with that fyftem of chro-
ui nology which refts on the authority of the Sacred.
Writings. This objection would no doubt be
of weight, if the high antiquity in queftion
were not reftricted merely to the globe of the
earth, but were alfo extended to the human
race. That the origin of mankind does not go
back beyond fix or feven thoufand years, is a
pofition fo involved in the narrative of the Mo-
faic books, that any thing inconfiftent with it,
would no doubt fland in oppofition to the
teftimony of thofe ancient records. On this
fubject, however, geology is filent; and the

high as any authentic monuments extend, refers

j

i hitory of arts and fciences, when traced as
f

j the

ate

126 ILLUSTRATIONS OF THE

the beginnings of civilization to a date not very
different from that which has juft been men-
tioned, and infinitely within the limits of the
moft recent of the epochas, marked by the phy-
fical revolutions of the globe.

On the other hand, the authority of the Sa.

cred Books feems to be but little interefted in

what regards the mere antiquity of the earth it-°

felf; nor does it appear that their language is to
be underftood literally concerning the age of
that body, any more than concerning its figure
or its motion. The theory of Dr Hutton ftands
here precifely on the fame footing with the fyf-
tem of Copernicus; for there is no reafon to
fuppofe, that it was the purpofe of revelation to
furnifh a ftandard of geological, any more than
of aftronomical {cience. It is admitted, on all
hands, that the Scriptures are not intended to
refolve phyfical queftions, or to explain matters
in no way related to the morality of human
actions ; and if, in confequence of this princi-
ple, a confiderable latitude of interpretation were
not allowed, we fhould continue at this moment
to believe, that the earth is flat ; that the fun
moves round the earth; and that the circum-

ference of a circle is no more than three times |

its diameter. -
It is but reafonable, therefore, that we fhould
extend to the geologift the fame liberty of fpe-
culation,

HUTTONIAN THEORY. 127

culation, which the aftronomer and mathema-

tician are already in poffeffion of; and this may

be done, by fappofing that the chronology of
Moszs relates only to the human race. This

liberty is not more neceflary to Dr Hutton than

to other theorifts. No ingenuity has been able

to reconcile the natural hiftory of the globe

with the opinion of its recent origin; and ac-

cordingly the cofmologies of Kirwan and De
Luc, though contrived with more mineralogical
{kill, are not lefs forced and unfatisfactory than

thofe of Burnet and Whitton.

126. It is impoffible to look back on the fyf-
tem which we have thus endeavoured to illuf-
trate, without being flruck with the novelty and
beauty of the views which it fets before us. The
very plan and fcope of it diftinguifh it from all
other theories of the earth, and point it out as
a work of great and original invention. ‘The
fole object of fuch theories has hitherto been,
to explain the manner in which the pre-
fent laws of the mineral kingdom were firft
eftablifhed, or began.to exift, without treating
of the manner in which they now proceed, and

T _ by which their continuance is provided for. The

authors of thefe theories have accordingly gone
back to a ftate of things altogether unlike the
prefent, and have confined their reafonings, or

their

i28 ILLUSTRATIONS OF THE

their fictions, to a crifis which never has exifted
but once, and which never can return, Dr
Hutton, on the other hand, has guided his in-
veitigation by the philofophical maxim, Caufam
naturalem et afiduam querimus, non raram et
fortuitam. His theory, accordingly, prefents us
with a fyftem of wife and provident economy,
where the fame inftruments are continually em-
ployed, and where the decay and renovation of
foflils being carried on at the fame time in the
different regions allotted to them, preferve in
the earth the conditions effential for the fupport
of animal and vegetable life. We have been
long accuftomed to admire that beautiful ton-
trivance in nature, by which the water of the
ocean, drawn up in vapour by the atmofphere, im-
parts, in its defcent, fertility to the earth, and be-
comes the great caufe of vegetation and of life ;
but now we find, that this vapour not only ferti-
lizes, but creates the foil; prepares it from the fo-
lid rock, and, after employing it in the great ope-
rations of the furface, carries it back into the re-
gions where all its mineral charaGers are renew-
ed. Thus, the circulation of moifture through
the air, is a prime mover, not only in,the annual
fucceffion of the feafons, but in the great geolo-

gical cycle, by which the wafte and reproduc-

tion of entire continents is circumfcribed. Per-
haps a more ftriking view than this, of the wil-
dom

ani

HUTTONIAN THEORY. 128

dom that prefides over nature, was never pre-
fented by any philofophical fyftem, nor a great-
er addition ever made to our knowledge of final
caufes. It is an addition which gives confiftency
to the reft, by proving, that equal forefight is ex-
erted in providing for the whole and for the
parts, and that no lels care is taken to maintain

the conftitution of the earth, than to preferve

the tribes of animals and vegetables which dwell
on its furface. In a word, it is the peculiar ex-
cellence of this theory, that it afcribes to the
phenomena of geology an order fimilar to that
which exifts in the provinces of nature with
which we are beft acquainted ; that it produ:
ces feas and continents, not by accident, but by
the operation of regular and uniform caufes ;
that it makes the decay of one part fubfervient
to the reftoration of another, and gives ftability
to the whole, not by perpetuating individuals,
but by reproducing them in fucceffion.

127. Again, in the detail of this theory, and
the ample induGion on which it is founded, we
meet with many facts ‘and obfervations, either
entirely new, or hitherto very imperfectly un-
derftood. Thus, the veins which proceed from

_ Imafles of granite, and penetrate the incumbent

{chiflus, had either efcaped the obfervation of
former mineralogifts, or the importance of the
phenomenon had been entirely overlooked. Dr

Hutton

130 ILLUSTRATIONS OF THE

Hutton has defcribed the appearances with great
accuracy, and drawn from them the moft inte.
refting conclufions. At the jun@tion of the pri-
mary and fecondary ftrata, the faéts which he

has noted had been obferved by others; but no.

one | think had fo fully underflood the language
which they fpeak, or had fo clearly perceived
the confequences that neceffarily follow from
them. He is the firt who diftin@ly pointed
out the characters which diftinguith whinftone
from lava, and who explained the true relation
that fubfifts between thefe fubftances. He alfo
difcovered the induration of the ftrata, in con-
tact with veins of whin, and the charring of the
coal in their vicinity. His theory alfo enabled
him to determine the affinity of whinftone and
granite to one another, and their relation to the
other great bodies of the mineral kingdom.

To the obfervations of the fame excellent
geologift, we are indebted for the knowledge of
the general and important ta@, that all the hard
fubtiances of the mineral kingdom, when ele-
vated into the atmofphere, have a tendency to
decay, and are fubje& to a difintegration and
wafte, to which no limit can be fet but that of

their entire deftru@iion; that no provifion 18 —

made on the turface for repairing this watte, and
that there, no new foffil is produced ; that the
formation of all the varied {cenery which the

furtace

VS ee ee eS E R

HUTTONIAN THEORY. 131.

furface of the earth exhibits; depends on the
operation of caufes, the momentary exertions of
which are familiar to us, though we knew not
before the effects which their accumulated ac-
tion was able to produce. Thefe are faéts in
the natural hiftory of the earth, the difcovery
of which is due to Dr Hutton; and, fhould we
lay all further fpeculation afide, and confider
the theory of the earth as.a work too great to be
attempted by man, we muft ftill regard the phe-
nomena and laws juft mentioned, as forming a
folid and valuable addition to our knowledge.
128. If we would compare this theory with
others, as to the invifible agents which it €m-
ploys, we muft confider, that fire and water are
the two powers which all of them muft make ufe
of, fo that they can differ from one another only
by the way in which they combine thefe powers.
In Dr Hutton’s fyftem, water is firt employed |
to depofite and arrange, and then fire to confo-
lidate, mineralize, and laftly, to elevate the ftra-
ta; but, with refpeé ta the unftratified or cry-
ftallized fubfiances, the ation of fire only is
recognifed. The fyftem having leaft affinity to
this is the Neptunian, which afcribes the for-

i mation of all minerals to the action of water

alone, and extends this hypothefis even to the
unftratified rocks. Here, therefore, the a¢tion
of fire is entirely excluded ; and the Neptunifts

; I2 have

132. ILLUSTRATIONS OF THE

have certainly made a great facrifice to the love
of truth, or of paradox, in rejecting the affift.
ance of fo powerful an auxiliary *. i
129. In the fyftems which employ the ssd
of the latter element, we are to look for a great-
er refemblance to that of Dr Hutton, though
many and great marks of diftinction are eafily
perceived. In the cofmologies, for example, of
Leisnirz and Burron, fire and water are both
employed, as well as in this; but they are em-
ployed in a reverfe order.” Thefe philofophers
introduce the action of fire firt, and then. the
action of water, which is to invert the order of
nature altogether, as the confolidation of the
rocks muft be pofterior to their ftratification.
Indeed, the theory of Buffon is fingularly de-
fective : befides inverting the order of the two
great operations of ftratification and confolida-
tion, and of courfe giving no real explanation of
the latter, it gives no account of the elevation, or
highly inclined pofition of the ftrata ; it makes
no diftin@ion between ftratified and unftratified
bodies, nor does it offer any but the moft unfa-
tisfactory explanation of the inequalities of the
earth’s furface. This fyftem, therefore, has but
a very diant refemblance to the Huttonian

theory +.
130. The fyftem of Lazzaro Moro has been
remarked as approae hing nearer to this theo-
ry

* NOTE xxiii. t Nove xxiv.

HUTTONIAN THEORY. 133

it ty than any other; and it is certain, that one
} very important principle is common to them
Ney both. The theory of the Italian geologift was

ca. chiefly directed to the explanation of the re-
tet ‘ mains of marine animals, which are found in
fh mountains far from the fea; and it appears to,
Y | have been fuggefted to him by the phenomenia
nh of the Campi Phlegrai, and by the produdtio:n
7 = of the new ifland of Santorini in the Archipt2-
et j lago. He accordingly fuppofes, that the iflancls
t and continents have been all raifed up, like the
ni above-mentioned ifland, from the bottom of tlhe
tht fea, by the force of volcanic fire: that thefe
a fires began to burn under the bottom of the
bk ocean, foon after the creation of the world, when

as yet the ocean covered the whole earth: that
they at firft elevated a portion of the land; and
in this primitive land no fhells are found, as the
original ocean was deftitute of fifh. The vol-
canoes continuing to burn; under the fea, after
the creation of animated nature, the firata that
were then raifed up by their action were full of
fhells and other marine objects; and, from the
violence with which they were elevated, arofe
the contortions and inclined pofition which they
_. frequently poffefs *

Se. 13 This

* Dé Croftacei, et degli altri Marini Corpi, che fi
trovano fu’ Monti: di Ant. Lazzaro Moro, Vinezia.
1740.

134 ILLUSTRATIONS OF THE

This fyftem is imperfe&, as it makes no pe-
culiar provifion for the confolidation of the ftra.
ta, which, according to it, as well as the Nep-
tunian fyftem, muft be afcribed to the action,
not of fire, but of water. No account is given

«of the mineralization of the fhells found in the
Í trata, or of the difference between them. and
tlie fhells found loofe at the bottom of the fea;
aiid no diftinction is made between ftratified
and unftratified fubftances. But, with all this,
Lazzaro Moro has certainly the merit of having
perceived, that fome other power than that
which depofited the ftrata, muft have been em-
ployed for their elevation, and that they have
endured the action of a difturbing force.

131. From this comparifon it appears, that
Dr Hutton’s theory is fufliciently diftin&, even
from the theories which approach to. it mof
nearly, to merit, inthe ftrictett fenfe, the appel-
lation of new and original. There are indeed
few inventions or difcoveries, recorded in thë
hiftory of fcience, to which nearer approaches
were not made before they were fully unfolded.
It therefore very well deferves to be diftinguith-
ed by a particular name; and, if it behoves us
to follow the analogy obferved in the names of
the two great fyftems, which at prefent divide
the opinions of geologifts, we may join Mr Kir-
wan in calling this the PLuronic System. For

my

HUTTONIAN THEORY. 135

my own part, I would rather have it characteriz-
ed by a lefs fplendid, but jufter name, that of
the Hurronrtan THEORY.

132, The circumftance, however, which gives
to this theory its peculiar character, and exalts it
infinitely above all others, is the introduétion
of the principle of preffure, to modify the effects
of heat when applied at the bottom of the fea.
This is in fact the key to the grand enigma of
the mineral kingdom, where, while one fet of >
phenomena indicates the action of fire, another
fet, equally remarkable, feems to exclude the
poflibility of that action, by prefenting us with
mineral fubftances, in fuch a ftate as they could
never have been brought into by the operation
of the fires we fee at the furface of the earth.
Thefe two claffes of phenomena are reconciled
together, by admitting the power of compreflion
to confine the volatile parts of bodies ‘when heat
is applied to them, and to force them, in many
inflances, to undergo fufion, inftead of being
calcined or diffipated by burning or inflamma-
tion. In this hypothefis, which fome affe& to
confider as a principle gratuitoufly aflumed, there
appears to me nothing but a very fair and legi- »
timate generalization of the properties of heat.
Combuttion and inflammation are chemical pro-
ceffes, to which other conditions are required,
befides the prefence of a high temperature. The

I 4 flate

136 ILLUSTRATIONS OF THRE

ftate of the mineral regions makes it reafonable
to prefume, that thefe conditions are wanting
in the bowels of the earth, where, of confe:
quence, we have a right to look for nothing but
expanfion and fufion, the only ‘operations which
feem effential to heat, and infeparable from the
application of it, in certain degrees, to certain
fubitances. Though this principle, therefore,
had no countenance from analogy, the admirable
fimplicity, and the unity, which it introduces
into the phenomena of geology, would fufficient-
ly juftify the application of it to the theory of
the earth,

As another excellence of this theory, I may,
perhaps, .be allowed to remark, that it extends
its confequences beyond thofe to which the au-
thor of it bas himfelf adverted, and that it
ailords, which no geological theory has yet done,
a fatisfaCtory ‘explanation of the {pheroidal fi-
gure of the earth *,

133. Yet, with all thefe cir
jinality, grandeur, and fimplicity in its favour,
with the addition of evidence as demonftrative
as the nature of the fubje@ will admit, this
theory has probably many obftacles to overcome,
before it meet the general approbation. The (
greatnefs of the objects which it fets before us,
alarms the imagination; the powers which it
fuppoies to be lodged in the fubterraneous re-

gions,

n

ces of ori-

* NOTE xxv.

HUTTONIAN THEORY. 137

gions; a heat which has fubdued the moft re-
‘frattory rocks, and has melted beds of marble
and quartz; an expanfive force, which has fold-
ed up; or broken the ftrata, and raifed whole
continents from the bottom of the fea; thefe
are things with which, however certainly they
= may be proved, the mind cannot foon be fami-
zf Jiarifed. ‘The change and movement alfo, which
this theory afcribes to all that the fenfes declare
“~~ to be moft unalterable, raife up againft it the
ti {ame prejudices which formerly oppofed the be-
“lief in the true fyftem of the world ; and it af-
E fords a curious proof, how little fuch preja-
) dices are fubje@ to vary, that as ARISTAR-
i cHus, an ancient follower of that fyftém, was
t charged with impiety formoving the everlafting
i} Vasra from her place, Dr Hutton, nearly on
i the fame ground, has been fubjected to the very
I} fame accufation. Even the length of time
il which this theory regards as neceflary to the re-
3 } volutions of the globe, is looked on as belong-
| ing to the marvellous; and man, who finds
himfelf conftrained by the want of time, or of
{pace in almoft all his undertakings, forgets,
that in thefe, if in any thing, the riches of na-
ture rejects all limitation *. ?
The evidence which muft be oppoled to all |
thefe caufes of incredulity, cannot be fully un-
deritood without much ftudy and attention.
| ae It

* NOTE xxvi.

138 ILLUSTRATIONS OF THE

It requires not only a careful examination of
particular inftances, but comprehenfive views
of the whole phenomena of geology ; the com.
parifon of things very remote with one ano-
ther; the interpretation of the obfcure by the
luminous, and of the doubtful by the decifive ap.
pearances. The geologift muft not content him:
felf with examining the infulated {pecimens of
his cabinet, or with purfuing the nice fubtleties
of mineralogical arrangement; he muft ftudy
the relations of foffils, as they actually exift;
he mutt follow nature into her wildeft and mof
inacceflible abodes; and mutt fele&, for the
places of his obfervations, thofe points, from
which the variety and gradation of her works
can be moft extenfively and accurately explored.
Without fuch an exag and comprehenfive fur-
vey, his mind will hardly be prepared to relifh
the true theory of the earth. “ Narure-enim
vis atque majeftas omnibus momentis fide caret,
Ji quis modo partes atque non totam complectatur
animo *,”’

134. If indeed this theory of the earth is as
well founded as we fuppofe it to be, the lapfe
of time muft neceflarily remove all obje&tions to
it, and the progrefs of {cience will only develope —
its evidence more fully. As it ftlands at pre-

fent;

>

* Prin. Hitt, Nat. lib. vii. cap. i.

HUTTONIAN THEORY. 136

fent, though true, it muft be ftill imperfed ;
and it cannot be doubted, that the great prin-
ciples of it, though eftablifhed on an immove-
i able bafis, muft yet undergo many modifica-
‘ tions, requiring to be limited, in one place, or to
be extended, in another. A work of fuch varie-
| ty and extent cannot be carried to perfection
ag by the efforts of an individual. Ages may be
te required to fill up the bold outline which Dr
h : Hutton has traced with fo mafterly a hand ;. to
et = detach the parts more completely from the. ge-
ln — neral mafs; to adjuit the fize and pofition of
Il the fubordinate members; and to give to the
ft whole piece the exa@ proportion and true co-
Wi louring of nature.
lone This, however, in length of time, may be €X-
eh pe&ed from the advancement of fcience, and
ri from the mutual affiftance which parts of know-
i ledge, feemingly the moft remote, often afford
oi toone.another. Not only may the obfervations
Į of the mineralogift, in tras yet unexplored,
complete the enumeration of geological facts;
«, and the experiments of the chemift, on fubftan-
je ces not yet fubjeĝëd to his analyfis, afford
| amore intimate acquaintance with the nature
of foffils, and a meafure of the power of thofe
= chemical agents to which this theory afcribes
fuch vaft effects: but alfo, from other {ciences,
lefs dire@tly connected with the natural hiftory
of

‘Nt

vimi

ï40 ILLUSTRATIONS, &¢.

of the earth, much information may be received, |

The accurate geographical maps and furveyg

which are now making ; the foundings; the oh.
fervations of currents ; the baromettical meafure. —

ments, may all combine to afcertain the reality,
and to fix the quantity of thofe changes which
terreftrial bodies continually undergo. Every
new improvement in fcience affords the means

of delineating more accurately the face of na. _

ture as it now exifts, and of tran{mitting, to
future ages, an account, which may be com:
pared with the face of nature as it fhall then
exift. If, therefore, the fcience of the prefent
times is deftined to furvive the phyfical revo-
lutions of the globe, the Hurronian THEORY
may be confirmed by hiftorical record ; and the
author of it will be remembered among the il-
luftrious few, whofe fyftems have been verified
by the obfervations of fucceeding ages, fupport-
ed by facts unknown to themfelves, and efta-
blifhed by the decifions of a tribunal, flow, but
_ infallible, in diftinguifhing between truth and
falfehood. 3

NOTES —
i

o
=
al

NOTES ann ADDITIONS.

j

l

|

[ 143 ]

NOTES anp ADDITIONS.

Note tr. § 2.

Origin of calcareous rocks.

134. WL has been aflerted, that Dr Hutton

went further than is ftated at § 2., and
maintained all calcareous matter to be originally
of animal formation. This pofition, however, is `
fo far from being laid down by Dr Hutton, that it
belongs to an inquiry which he carefully avoid-
ed to enter on, as being altogether beyond the
limits of philofophical inveftigation.

He has indeed no where treated of the firi
origin of any of the earths, or of any fubftance
whatfoever, but only of the transformations
which bodies have undergone fince the prefent
laws of nature were eftablifhed. He confidered
this lat as all that a fcience, built on experi-
ment and obfervation, can poflibly extend to;
and willingly left, to more prefumptuous in-

quirers, the tafk of carrying their reafonings
beyond the boundaries of nature, and of unfold-
ing the properties of the chaotic fluid, with as
much minutenefs of detail, as if they were de-
feribing

M

144 ILLUSTRATIONS OF THE

{cribing the circumftances of a chemical procef
which they had a&tually witneffed. |

The idea of calcareous matter which really be.
longs to the Huttonian Theory, is, that in all
the changes which the terraqueous globe has
undergone in paft ages, this matter exifted, as
it does now, either in the form of limeftone and
marble, or in the compofition of other ftones,
or in the ftate of corals, hells, and bones of
animals. It may be true, that there jis no
particle of calcareous matter, at prefent exift-
ing on the furface of the earth, that has not,
at fome time, made a part of an animal bo-
dy ;-but of this we can have no certainty, nor
is it of any importance that we fhould. It
is enough to know, that the rocks of marble and
limeftone contain in general marks of having
been formed from. materials collected at the
bottom of the fea; and of this a fingle cockle-
fhell, or piece of coral, found included in a rock,
is a fufficient proof with refpe@ to the whole
mafs of which it makes a part..

The principal obje& which Dr Hutton had
in view when he fpoke of the maffes of mar-
ble and limeftone, as compofed of the calca- 7
reous matter of marine bodies *, was to prove, |
that they had been all formed-at the bottom of

| the

-

eames 4 —_

* Theory of the Earth, vol. i, p. 23, 246

af ae E
——
ae x —
>

HUTTONIAN THEORY. _ 145

the fea, and from materials there depofited. His
general conclufion is, “ that all the ftrata of the
earth, not only thofe confifting of fuch calca-
reous maffes, but others fuperincumbent upon

thefe, have had their origin at the bottom of

the fea, by the collection of fand and gravel, of
fhells, of coralline and cruftaceous bodies, and
of earths and clays varioufly mixed, or feparated
and accumulated. This is a general conclufion,
well authenticated by the appearances of nature,
and highly important in the natural hiftory of

| the earth *.’’

_ 135. In his Geological Efays, Mr Kirwan fays,

that “ fome geologifts, as Buffon, and of late Dr
Hutton, have excluded calcareous earth from
the number of the primeval, afferting the maffes
of it we at prefent behold to proceed from fhell-
fih. But, in addition to the unfounded fuppo-
fition, that fhell-fith, or any animals, poffefs the
power of producing any fimple earth, thefe phi-
lofophers fhould have confidered, that, before
the exiftence of any fifh, the ftony maffes that
inclofe the bafon of the fea, muft have exifted ;
and, among thefe, there is none in which calca-
reous earth is not found. Dr Hutton endea-

\ Yours to evade this argument, by fuppoling the.

world we now inhabit to have arifen from the
ruins

x Theory of the Earth, vol. i. p. 26.

146 ILLUSTRATIONS OF THE

ruins and fragments of an anterior, without
pointing at any original. If we are thus to
proceed zn infinitum, I fhall not pretend to fol-
low him; but, if he ftops any where, he will
find the fame argument equally to occur *,”
The argument here employed would certain.
ly be conclufive againft any one, who, in dif.
puting about the jfirff origin of things, fhould
deny that the calcareous is as ancient as any
other of the fimple earths. But this has nothing
to do with Dr Hutton’s {peculations, which, as
has been juft faid, never extended to the firft
origin of tubftances, but were confined entirely
to their changes ; fo that what he afferts concern-

ing the calcareous rocks, is no more than that _

thofe which we now fee have been formed from
loofe materials, depofited at the bottom of the fea.
It was not therefore in order to evade Mr Kir-
wan’s argument, as the preceding paffage would
lead us to believe, that he fuppofed the world
which we now inhabit to have arifen from the
ruin and wafte of an anterior world ; but it was
becaufe this feemed to him a conclufion which
neceffarily followed from the phenomena of
geology, and it wasaconclufion that he had
deduced long before he heard of Mr Kirwan’s

objections to his fyftem. Inftead of an evafion, `

therefore,

——)

x Geal. Efays, pe I3.

EP OS E E PA A

HUTTONIAN THEORY: 144

ei i PF

at therefore, any one who confiders the fubjeét
dng fairly, will fee, in Dr Hutton’s reafoning, no-
he À | thing but the caution of a philofopher, wlio
ré) | wifely confines his theory within the fame limits
by which nature has confined his ‘experience
ET and obfervation.

d It is neverthelefs true, that Dr Hutton has

' R fometimes expreffed himfelf as if he thought
a that the poen eae argons — are all compo-
hick, fed of animal remains *, ‘This conclufion, how-
the ever, is more general than the facts warrant >

M and, from fome incorrectnefs or ambiguity of
enag language, is certainly more general than he in-
onen tended. The idea of calcareous rocks, on which
ian tt} he argues throughout his whole theory, is precife-

ed int ly that which is ftated in the preceding article:

Mr Kr

> woul Note Ii. § 6.

e wif Origin of coal.

om t

t it i 136. The vegetable origin of coal feems to be
hid fufficiently proved by the reafoning in § 5. and

6.; and that reafoning will appear ftill more ia-
© tisfađorý, from what is faid at § 25. and 29.
| A concerning the confolidation of this fol. Dr
fi ~ Hutton has treated both cf the matter of coal
oa K 2 and
ot Theory of the Earth, vol. 1. p. 23:

148 ILLUSTRATIONS OF THE

and of its confolidation, Part. I. Chap. 8. of his
Theory of the Earth *. |

The notion, however, that coal is of vegeta.
ble origip, is not peculiar to this theory, but
has been for fome time the prevailing opinion,
Buffon fuppofes this mineral to be formed from
vegetable and animal fubftances, the oil and fat
of which have been converted into bitumen by
the action of acids}. A fundamental miftake,
however, is committed by this author, and by
M. Gensanne, (author of the natural hiftory of
Languedoc), on whofe obfervations he greatly re-
lies, in confidering coal as confifting of bitumen
united to earth, thus omitting the only ingre-
dient effential to coal, namely the carbon or
charcoal. This may truly be confidered as the

eflential part, becaufe coal may exift without —

bitumen, as in the inftance of blind-coal, but
not without charcoal.

Another theory of coal, very analogous to Dr
Hutton’s, is that of Arpurno, profefior of mi-
neralogy at Venice, in which he fuppofes it
formed from vegetable and animal remains from
the land and fea, but chiefly from the latter $.

* Vol. i. p: 558, &c.

+ Hift. Nat. des Mineraux, tom. i. p. 429. 4to edit.

ł Saggio Fifico-mineralogico del Sig. Giovy, Arduinoy
Atti di Siena, tom. v, P. 228, 281, &e,

This —

een
t

|

l.

1
|

HUTTONIAN THEORY. 149

This theory of coal is contained in Dr Hutton’s,
W in which the animal and vegetable remains muft
= be fuppoied to come both from the earth and
It the fea. It feems to be without any good rea-
lfy fon that Arduino confiders the fea as the chief
iy fource of thefe materials. His remarks, how-
mj) ever, are very ingenious, and deferving of atten-
iy tion. |

Thefe accounts of the origin of coal are all
nearly the fame ; it is in what relates to the di-
, . tinction between the common coal, in which
| there is no ligneous ftru@ure, and thofe varieties
of it in which that ftructure is apparent, and
again in explaining the confolidation of both,
_ that the theory, laid down here, is peculiar.

137. Some other mineralogifts refer one of
the ingredients of coal to the vegetable king-
dom, but not the other. Unable to refift the
conviction which arifes from the fibrous ftruc-
ture of parts of ftrata, and even entire ftrata of
coal, they have fuppofed, that wood, which had
been fomehow buried in the earth, or perhaps
depofited at the bottom of the fea, had become
impregnated with bitumen, which laft, however,
_. they confider as of mineral origin. This appears
-to be the opinion of Lehman, and alfo of fome
very late writers. There feems, however, to be
hardly lefs reafon for referring the origin of one
part of coal to the vegetable or animal kingdom

K 3 than

aoe
Pa
=

730 ILLUSTRATIONS OF THE |

than another. The two laft are certainly capable
of furnifhing both the carbonic and bituminous
parts; and therefore, to derive thefe from dif.
ferent fources, is at leaft a very unneceflary com. ©
plication of hypothefes.

138. Another explanation of coal, very dif
ferent from any of the preceding, has lately been
advanced and fet up in oppolition to the Hut. —
tonian Theory. Mr Kirwan *, the only minera- `

ee

logift, I believe, who has attempted to derive both
the carbonic and bituminous matter of coal from
the mineral kingdom, diftinguifhes between
wood-coal and mineral-coal, and gives a theory
entirely new of the formation of the latter.
Wood-coal is that in which the ligneous ftruc-
ture is fo apparent, as to leave no doubt of its

-

vegetable origin; mineral coal is that in which
no luch ftructure can be difcovered, and is the
fame which Dr Hutton derives from the vegeta-
ble juices, and other remains, comminuted, dif-
perfed, carried into the fea, and there precipi-
tared, fo as to unite with different proportions of
earth, and to become afterwards mineralized.
Thefe two fpecies of coal, which the Hutto- |
nian theory confiders as gradations of the fame, —

z,

fubitance, Mr Kirwan regards as perfectly di-
fing, conftituting two minerals, of an origin
an

Se o

# Geol. Effays, eflay vil. p. 290.

HUTTONIAN THEORY. 151

and formation entirely different. He therefore
endeavours to afcertain the diftinguifhing: cha-
racters of each, confidered geologically.

139. But here the leading diftinction, implied
in all the reft, that the two kinds of coal are ne-
ver found in the fame bed, but always in differ-
ent fituations, and with different laws of ftrati-
fication, is exprefsly contradicted by matter of

fact. Coal, as is faid above, with its ligneous

texture quite apparent, and coal with no fuch
firucture vifible, are often found in the fame
feam, are brought up from the fame mine, and
united in the fame fpecimen. I have a fpeci-
men from a bed of coal, in the Ifle of Sky, found
under a bafaltic rock, confifting of a ligneous
part, which graduates into one in which there is
no veftige of a fibrous texture, and in which the
furface is fmooth and gloffy, with a fracture al-
moft vitreous. The upper part of the fpecimen
is therefore perfe& wood-coal, and the under

part perfect mineral-coal, in the language of

Mr Kirwan; at the fame time that the tranfition
from the one to the other is made by infenfible
degrees. This fpecimen, were it perfectly fo-
litary, is fuflicient to prove the identity of the
two. fpecies of coal we are now {peaking of, and
to fhew, that the difference between them is ac-

_cidental, not effential, The fpecimen, however,

is far from being folitary ; the number of fimi-
K 4 lar

152 ILLUSTRATIONS OF THE

lar appearances is fo great, as hardly to have ef.
caped the obfervation of any mineralogift. Mr
Kirwan admits, that wood-coal is often found un-
der bafaltes*; but what is effential to be remark.
ed is, that, in this inftance, we have both the
wood-coal, and the common mineral-coal, lying
under that rock, and the one paffing gradually
into the other. It appears, indeed, that many of
the facts which Mr Kirwan produces, in treating
of what he calls carboniferous foils, are quite in-
confiftent with the diftin&ion he would make
between wood-coal and mineral-coal +,

140. It is, however, true, that there are in-
ftances in which the wood-coal, or foflil- wood,
as it is ufually called, forms entire beds, quite
unconnected with the ordinary coal, and ftrati-
fied in fome refpects differently. Such is the
Bovey coal in Devonfhire, the wood-coal in the
north of Ireland, and perhaps the Surturbrandt of
Iceland. With refpe& to the Bovey coal, it does
by no means anfwer to one of Mr Kirwan’s re-
marks, viz. that late obfervations have afcertained,
that no fuch parallelifm of the beds, as in mine-
ral-coal, nor even any diftiné& number of ftrata,
is found. In the Bovey coal, the number of
ftrata is very well defined, by beds of clay re-
gularly interpofed ; but as to the extent of thefe

beds,

* Geol. Effays, p. 310. t ibid. p. 311.

a in R ERE re

ij
b-

HUTTONIAN THEORY. 153

beds, the coal having been worked only at one
place, and by an open pit, without any extenfive
fubterraneous excavation, nothing is known with
certainty.

In the Bovey coal too, I muft obferye, shotigh
its beds have the ligneous ftructure very difting,
the clay interpofed between thefe beds, which
is but little indurated, contains a great deal of
coaly matter, in the form of thin flakes, inter-
{perfed through it. So far as I know, there are
no mineral veins nor fhifts, nor any bed of in-
durated ftone, that accompany this coal; fo that,
though one cannot doubt of its vegetable origin,
fome doubt may be entertained concerning
the. nature of the mineralizing operations, to
which it has been fubje@ed. Theconfideration
of thefe, however, does not belong to the prefent
argument ; and the peculiarities of this femi-
mineralized coal, as it may be called, have
nothing to do with the general queftion, whe-

| ther wood-coal and mineral-coal are the fame

fubftance ; about which quettion, if the grada-

T tions are properly confidered, I think, no rea-

fonable doubt can remain.
141. One of Mr Kirwan’s objections to the

vegetable origin of coal, is founded on this fact,

= that there is, in the mufeum at Florence, a cel-

lular fandftone, the cells of which are filled with

genuine mineral coal, « Could this, (adds he)

have

154 ILLUSTRATIONS OF THE

have been originally wood *?”” The anfwer to
the interrogatory propofed here as a reduétio aq
abfurdum, is, that moft undoubtedly it may have
been wood. Sandftone with charred wood, that
is, with wood-coal in it, is not an uncommon
phenomenon in coal countries. I have feena
fpecimen of this kind from the Hales Quarry,
near Edinburgh, confifting of a piece of charred
wood, imbedded in fandftone; the wood was
much altered, but the remains of its fibrous

ftructure were diftin€ly vifible. This affordsa

perfect commentary on the fpecimen in the Flo.
rence cabinet.

142. If then it be granted, as I think it mutt,
that the two kinds of coal we have been fpeak-

ing of are of the fame origin, it is not very ne-

ceflary to enter on a refutation of Mr Kirwan’s
theory with refpect to either of them. His ac-
count of the formation of mineral-coal, however,
is fo fingular, that it cannot be a over with-
out remark.

Mr Kirwan fuppofes, rmo, That natural carbon
was originally contained in many mountains of
the granite and porphyritic order, and alfo in
filiceous f{chiftus ; and might, by difintegration
and decompofition, be feparated from the ftony
particles. 2do, That both petrol and carbon
are often contained in trap, fince hornblend,

which

—— aeaa N

* Geol. Effays, p. 324.

n ai

HUTTONIAN THEORY. 158

which has lately been found to contain carbon,
very frequently enters into its compofition.

“ My opinion : adds he) is, that coal mines, or
ftrata of coal, as well as the mountains in which
they are found, owe their origin to the difinte-
gration of primeval mountains, either now to-
tally deftroyed, or whofe height and bulk, in
confequence of fuch difintegration, are confider-
ably leffened ; and that thefe rocks, anciently
deftroyed, contained moft probably a far larger
proportion of carbon and petrol than thofe of
the fame denomination now contain, fince their
difintegration took place at fo early a period *.

“ By the decompofition of thefe mountains, the
felt{par and hornblend were converted into clay ;
the bituminous particles, thus fet free; reunited,

and were abforbed, partly by the argil, but

chiefly by the carbonaceous matter, with which
they have the greateft affinity. The carbo-
nic and bituminous particles, thus united, being
difficultly mifcible with water, and fpecifically
heavier, funk through the moift, pulpy, incohe-
rent argillaceous mafles, and formed the loweft
ftratum,’’ &c.

Such is Mr Kirwan’s theory of the formation
of coal, and nobody I think will difpute the
originality of it.

143. To

* Geol. Effays. p 328, &c.

156 ILLUSTRATIONS OF THE

143. To enter on a formal refutation of ap
opinion fo loaded with objeCtions, would be a
tafk as irkfome as unneceflary. A few obferya-
tions will fuffice.

The notion of the great degradation of moun-
tains, involved in this hypothefis, is the part of
it to which I am leaft difpofed to obje&. But
I cannot help reminding Mr Kirwan, that the
effects of wafte are not fuppofed lefs in this,
than in Dr Hutton’s theory ; and that he has
affumed the very principle,.of which that theo-
ry makes fo much ufe, though he has referved
to himfelf, as it fhould feem, the right of denying
it, when it does not accord with his fyftem. . It
is indeed worth while to compare what is faid
concerning the degradation of mountains, in the
above quotations, and {till more fully in the
book itfelf, with what is advanced concerning
their indeftruciibility, in another paflage of the
fame volume *:

“ All mountains are not fubje& to decay; for
inftance, fcarce any of thofe that confift of red
granite. The ftone of which the Runic rocks

1

have withftood decompofition for two

as

ire formed,
thoufand years, as their characters evince,” &c.
tic pillars, in general, bid defiance to
decay,” &c. He goes on to deny every ftep of
the degradation of land, by which it is watted,
carried

ET,
`

ée Badal
Balali

-e

: Page 436.

—
Pi
#

HUTTONIAN THEORY. = 57

carried into the fea, and {pread out over its bot-
tom, though all thefe are neceflary po/fulata in
his theory of the formation of coal. One can
be at no lofs about eftimating the value of a
fyftem, in which fuch grofs inconfiftencies make
a neceflary part.

144. The quantity of hornblend and filiceous
fchiftus, neceflary to be decompofed, in order to
produce the coal ftrata prefently exifting, is
enormous, and would lead to an eftimate of what
is worn away from the primeval mountains, far
exceeding any thing that Dr Hutton has {uppo-
fed. It is true, that Mr Kirwan, never at all
embarraifed about preferving a fimilitude be-
tween nature as fhe is now, and as fhe was here-
tofore, lays it down, that the part of the prime-
val mountains which is worn away, contained
much more carbon than the part which is left
behind. This, however, is an arbitrary fuppo-
fition ; and fince, in this fyftem, fuch fuppofi-
tions are fo eafily admitted, why may we not
conceive, in the primeval mountains, a more
copious fource of carbonic matter than horn-
blend or filiceous {chiftus? We have but to
imagine, that the diamond exifted among thefe
mountains in fuch abundance, as to conftitute
large rocks. This ftone being made up of
pure, or highly concentrated carbon, the ada-
mantine fummits of a fingle ridge, by their

- decompofition,

158 ILLUSTRATIONS OF THE

decompofition, might afford a carbonic bafis;
fufficient for the coal beds of all the furround.
ing plains.

145. We may alfo obje& to Mr Kirwan, that the
filiceous part of the mountains has not been che.
mically diffolved ; it has been only abraded and
wornaway. Mechanical action has reduced the
quartz to gravel and fand, but has not produced
on it any chemical change. ‘The carbon, there.
fore, could not be let loofe. Experiment, in-
deed, might be employed, to determine whether

the filiceous matter of the fecondary, and of.

the primary ftrata contains this fubftance in the
fame proportion.

Again, a more fatal fymptom can hardly be
‘imagined in any theory, than that, when the cir-
-cumftances of the phenomena to be explained are

a little changed, the theory is under the necefli-

a

ty of changing a great deal. Now, this is what

happens to Mr Kirwan’s theory, in the attempt
made to explain by it the ftratum of coal de-
fecribed in the Annales de Chimie *, as cutting a
mountain of argillaceous ftrata in two, at about
three-fourths of its height. This ftratum, Mr
Kirwan fays, muft have been formed by ¢tranjfu-
dation from the fuperior part of the mountain f.
Befides that this is a gratuitous fuppofition of a

thing,
* Tom. xi. p. 272. + Geol. Effays, p. 335:

: HUTTONIAN THEORY. 159

thing, without example, it involves in it an ab-

"oy furdity, which becomes evident the moment the
bai} _ queftion is afked, What occupied the place of
1 _ the coal-bed before the tranfudation from the
ej, UPPer part of the mountain? Has the liquid

í coal, as it percolated through the upper ftrata,
ed expelled any fubttance from the place it now
duj occupies? or has it been powerful enough to
PE nit up, or to float, as it were, the upper part
Dg

of the mountain ?

I The fituation of this bed of coal is not fingu-
nd g lar, and its formation is eafily explained on Dr
int _ Hutton’stheory. It is part of a ftratum of coal,
_ which has been depofited, like all others, at the
yt bottom of the fea ; from whence certain caufes,
ied’ of very general operation, have raifed it up, to-
ela gether with the attending ftrata: thefe ftra-
ei ta have fince been all cut down, and worn away
by the operations of the furface; and the moun-
tj tain, with the coal ftratum in the middle of it, is
Jj a part of them which has been left behind. There
in is no-wonder, that a coal ftratum fhould be
abe i found alternating with others, in a mountain,
{ any more than in the bowels of the earth, and
no more need of a feparate explanation *.

ih 146. After

di ; ee oe -
n * This ftratum of coal, which is defcribed by Has.

_ S8ENFRATZ, is remarkable for being in a mountain which
a rels immediately on primary {chiftus and granite.

160 ILLUSTRATIONS OF THE

146. After all, it may be afked, for what
purpofe is it that fo many incongruous and
ill-fupported hypothefes are thus piled on
one another? is it only to avoid afcribing the
carbonic and bituminous matter of coal to a
fubftance in which we know with certainty that
fuch matter refides in great abundance, in order
to derive it from other fubftances, in which a
fubtle analyfis has fhewn, that it exifts ina very
{mall proportion? Such reafoning is fo great a
trefpafs on every principle of common fenfe, not
to fay of found. philofophy, that, to beftow any
time on the refutation of it, is, in fome degree,
to fall under the fame cenfure.

Nore 111. § 7.

Primitive mountains.

147. The enumeration of the different kinds
of primary {chiftus, at § 7., is not propofed as
at all complete. It will be lefs defective, how-
ever, if we add to it talcofe fchiftus, and lapis-
ollaris or potftone*.

148. The rocks called here by the name of

primary, were firft diftinguifhed, as forming the
= bafis

—— al

* Kirwan’s Mineralogy, vol, i. p. 155.

n P”

HUTTONIAN THEORY. I6r

þafis of all the great chains of mountains, and
as conftituting a feparate divifion of the mineral
kingdom, by J. G. Lenman, director of the
Pruffian mines. See his work, intituled, Efai
dune Hiftoire Naturelle de Couches de la Terre *.
Thefe rocks were regarded by Lehman as parts
of the original nucleus of the globe, which had
undergone no alteration, but remained now fuch
as they were at firft created; and, agreeably to
this f{uppofition, he beftowed on them, and on the
mountains compofed of them, the name of pri-
mitive. He remarks, neverthelefs, their diftri-
bution into beds, either perpendicular to the ho-
tizon, or highly inclined, and the fuper-pofi-
tion of the fecondary, and horizontal ftrata.
However mineralogifts may now differ in their
theories from Lehman, they muft confider this
diftinction as a great ftep in the {cience of gEO-
logy, and very material to the right arrange-
ment of the natural hiftory of the earth.

149. Several mineralogifts have agreed with
him in the fuppofition, that thefe rocks area part
of the original ftru@ture of the globe, and prior to
all organized matter. Of this number is PAL-
Las}; and alfo De Luc, who applies the term

L primordial

* Tom. iii. p. 239, &c. The French tranflation is in
2759, but the original preface is dated at Berlin 1956.

t Obfervations fur la Formation des Montagnes.

162 ILLUSTRATIONS OF THE

primordial to the rocks in queftion, and confi-
ders them as neither ftratified nor formed by
water *. In his fubfequent writings, however,
he admits their formation from aqueous depofi-
tion, as the Neptunifts do in general, but holds
them to be more ancient than organized bodies,
150. Pini, profeffor of natural hiftory at Mi-
lan, has denied the ftratification of primitive
mountains, ina memoir on the mineralogy of
St Gothard, and in another on the revolutions
of the globe}. His reafonings are oppofed by
SAUSSURE f, and are certainly, in many refpeds,
very open to attack. ‘They proceed on a com-
parifon between the divifion of rocks, by what
is called the planes of their ftratification, and
their divifion by tranfverfe fiffures ; two things,
which he thinks fo much alike, that they ought
not to be referred to different caufes; and, as
the one cannot be regarded as the effect of aque-
ous depofition, fo neither fhould the other. This
is a very fallacious argument, becaufe it con-
founds two things that are effentially different;
and,

* Lettres Phyf. fur l'Hiftoire de la Terre, tom. ii.
p.206.

t Memoria fulle Rivoluzione del Globo Terreitre ;
Memorie della Societa Italiana, tom. v. p. 222, &c.

t Voyages aux Alpes, tom. Iv. § 1881,

ee ee ee

`

1
HUTTONIAN THEORY. 163

and, inftead of inquiring about a matter of fact,
inquires about its caufe. The truth is, that the
eng. difpute has arifen from not diftinguifhing the
w granite from the fchiftus mountains, and from
iy involving both under the name of primitive.
T M. Pini feems to be in the right, when he holds

_ the granite of St Gothard to be unftratified ; but

O .... |

i it is without any good reafon, that he would ex-
oy

ye tend the fame conclufion to the {chiftus of that
uttog

mountain. CHARPENTIER, and Sauflure, in his
laft two volumes, contend even for the ftratifica-
ME tion of granite *,

tt As the confent, if not univerfal, is very gene-
ral for the ftratification of the primary fchiftus,
U and the fa@ itfelf abundantly obvious, in almoft
lif all the inftances I have ever met with, I have
ge not confidered it as neceffary to enter here into
d! any argument on this fubject.

Th

coh x

m NOTE Iv. § 8.

a Primary ftrata not primitive.

A

j

$ I5I. An account of the fads referred to
§ 8., may be found in Hutton’s Theory, vol. i.

gi L 2 p- 332;

* See Note xv. on Granite.

164 ILLUSTRATIONS OF THE

p- 332, &c. To what is there faid, of the
fhells contained in the primary limeftone of
Cumberland, I muft add, that I have fince had
an opportunity of verifying the conjecture, that
the limeftone rock, in which the fhells were
found, near the head of Coni/ton Lake, is part of
the fame body of ftrata, where fhells were found,
in a quarry between Amblefide and Low-wood,
The limeftone of that quarry contains feveral ma-
rine objects; it is in ftrata declining about 10°
from the perpendicular, toward the S. E., and
forms a belt, ftretching acrofs the country from
N. E. ta 5. W.

In a quarry where the vabim fchiftus,

on the fouth fide of this limeftone belt, is worked

for pavement, are impreflions of what I think
may fafely be accounted marine objeés; they
have the form of fhells, are much indurated,
and full of pyrites. They feem to be of the fame
kind with the impreffions faid to be found ina
flate quarry, near the villaga of Mat in Swit-
zerland *.

Another fpot, affording inftances of fhells in
primary limeftone, is in Devonfhire. On the
fea-fhore on the eaft fide of Plymouth Dock,
oppofite to Stonehoufe, I found a fpecimen of
{chiftofe micaceous limeitone, containing a fhell

o

ell
a

* Hutton’s Theory, vol.i. p. :327.

HUTTONIAN THEORY. 165

of the bivalve kind: it was truck off from the
folid rock, and cannot poffibly be confidered as
an adventitious foffil.

Now, no rocks can be more decidedly prima-
ry than thofe about Plymouth. They confit of
calcareous ftrata, in the form either of marble
or micaceous limeftone, alternating with varie-
ties of the fame fchiftus, which prevails through
Cornwall to the weft, and extends eaftward into
Dartmoor, and on the fea-coaft, as far as the
Berry-head. Thefe all interfe@ the horizontal
plane, in a line from eaft to weft nearly ; they
are very erect, thofe at Plymouth being elevated
tothe north.
` Though, therefore, the remains of marine
animals are not frequent among the primary
rocks, they are not excluded from them; and
hence the exiftence of thell-fifh and zoophytes,
is clearly proved to be anterior to the formation
even of thofe parts of the prefent land which are
juftly accounted the moft ancient.

152. The rocks which contain fand or gravel,
or which are of a granulated texture, muft alfo be
confidered as carrying in themfelves a teftimony
of the moft unequivocal kind, of their being
derived from the detritus and wafte of former
tocks. Now, the fa@ ftated in the text, con-
cerning fand found in fehiftus, moft juftly ac-
counted primary, might be exemplified by actual

L 3 reference

166 ILLUSTRATIONS OF THE

reference to many fpots on the earth’s {urface,
A few fuch will be fufficient in this place.

St Gothard is a central point, in one of the
greateft tracts of primary mountains on the face
of the earth, yet arenaceous ftrata are found in
its vicinity. Between Ayrolo and the Hofpice
of St Gothard, Sauffure found a rock, compofed
of an arenaceous or granular pafte, including in
it hornblend and garnets. He is fomewhat un.
willing to give the name gres to this {tone,
which M. Beffon had done; but he neverthe-
lefs defcribes it as having a granulated ftruc-
ture *, ;

Among the moft indurated rocks that com-
pofe the mountains of this ifland, many are ares
naceous. Thus, on the weftern coaft of Scot-
land, the great body of high and rugged moun-
tains on the fhores of Arafaig, &c. from Ardna-
murchan to Glenelg, confifts, in a great mea-
fure, of a granitic fand{tone, in vertical beds.
This ftone fometimes occupies great tracts ; at
other times it is alternated with the micaceous,
or other varieties of primary {chiftus; it occurs,
likewife, in feveral of the iflands, and is a fof-
fil which we hardly find defcribed or named
by the writers on mineralogy. Much, alfo, of

* Voyages aux Alpes, tom. iv. § 1822,

HUTTONIAN THEORY. 167

4 highly indurated, but granulated quartz, is
found in feveral places in Scotland, in beds or
ftrata, alternated with the common {chiftus of
the mountains. Remarkable inftances of this may
be feen on the north fide of the ferry of Bala-
chulifh, and again on the fea-fhore at Cullen.
At the latter, the ftrata are remarkably regular,
alternating with different fpecies of {chiftus.
At the former, the quartz is fo pure, that the
ftone has been miftaken for marble.

Thefe examples are perhaps fufficient; but
I muĝ add, that in the micaceous and talcofe
{chifti themfelves, thin layers of fand are often
found, interpofed between the layers of mica or
talc. I have a f{pecimen, from the fummit of
one of the higheft of the Grampian mountains,
where the thin plates, of a talcky or afbeftine
fubftance, are feparated by layers of a very fine
quartzy fand, not much confolidated.

The mountain from which it was brought,
confifts of vertical ftrata, much interfected by
quartz veins. It is impoffible to doubt, in
this inftance, that the thin plates of the one

fubftance, and the {mall grains of the other,

were depofited together at the bottom of the
fea, and that they were alike produced from
the degradation of rocks, more ancient than any

which now exif.

L4 153. In

T
j
N

168 ILLUSTRATIONS OF THE

153. In the Neptunian fyftem, as improved
by Werner, an attempt is made to take off the
force of fuch inftances as are produced in § $,
9, and 151, &c. by diftinguithing rocks, as to
their formation, into three different orders,
the primitive, the intermediate, and the fecon-
dary, or, to {peak more properly, into primary,
fecondary, and tertiary. The fame mineralo-
gift diftinguifhes, among the materials of thefe
rocks, between what he terms chemical and me-
chanical depofites. By mechanical depofites,
are underftood fand, gravel, and whatever bears
the mark of fracture and attrition ; by chemical
depofites, thofe which are regularly cryftallized,
or which have a tendency to cryftallization, and
in which the action of mechanical caufes cannot
be traced. This diftinGion is founded in na-
ture, and proceeds on real and palpable differen-
ces; but the application made of it to the three
kinds of ftrata juft enumerated, feems by no
means entitled to the fame praife.

The primitive rocks contain, it is faid, none
but chemical depofites, and are entirely com-
pofed of them: the intermediate contain a mix-
ture of both, and alfo fome veftiges of organized
bodies: the fecondary confit almoft entirely of
the mechanical, or of the remains of fuch bo-
dies, with little of the chemical. The firft of
thefe, then, are held to contain no mark or vel-

tige

HUTTONIAN THEORY. 169 :

l
my = tige whatfoever of any thing more ancient than
1 themfelves, and are, in the ftricteft fenfe, prime-
i wal, or formed of the firt materials, depofited
by the immenfe ocean which originally encom-
paffed the globe.
wf After them were formed the intermediate,
w moftly confifting of chemical depofites, but con-
th taining alfo fome animal remains, and fome fpoils
th from the land, fubjected to the various kinds
lt, of deftruction, which even then made a part of
ft the order of nature. Thefe rocks, it is alleged,
are chiefly argillaceous, are lefs indurated than
w the primary, and not interfeGed by veins of
i quartz.
al The fecondary were formed from the re-
Mm mains of the other two, and contain more me-
œ chanical depofites than any other.
m This {ketch of what I underftand to be Wer-
hte ner’s opinion concerning the different formation
w Of the ftrata, is chiefly taken from a view of his
fyftem, in the Journal de Phyfique for 1800.
154. The main objeGion to the diftinGion here
made between the primary and the intermediate
ftrata, is founded on the fas that have been
jut ftated. The fandftone of St Gothard is
from a country having every character of a pri-
mary one in the higheft perfection. The in-
ftances I have mentioned from the Highlands
of Scotland, are from mountains, lefs elevated
indeed

EE,

aiii ie

= & S&S 2

er

170 ILLUSTRATIONS OF THE

indeed than the Alps, but where the rock tg
micaceous, talcofe, or filiceous, in planes ereĝ
to the horizon, and interfected by veins of
quartz. ‘The fhells from Plymouth are from
a rock, that Werner would, I think, admit
to be truly primitive. Thofe from the lakes,
alfo, are from the centre of a country, occu-
pied by porphyry, fchorl, hornftone-fchiftus,
„and many others, about the order of which
there can be no difpute. It is true, that in this
tract there are argillaceous ftrata, of the kind
that might be accounted intermediate, were
they not interpofed among thofe that are cer.
tainly primary ; and this very intermixture
fhews, how little foundation there is for the di-
ftinGion attempted to be made between the for-
mation of the one and of the other. If there is
any principle in mineralogy, which may be con-
fidered as perfectly afcertained, it is, that rocks
fimilarly ftratified, and alternated with one ano-
ther, are of the fame formation.

Hence we conclude, that there is zo order of
Strata yet known, that does not contain proofs
of the exiftence of more ancient ftrata. We
fee nothing, in the ftrict fenfe, primitive. It
muft be underftood, that what is here faid has
no reference to granite, which Ido not confi-
der as a ftratified rock, and in which neither the

remains of organized bodies, nor fand, have I
believe

a
po
|

3 HUTTONIAN THEORY. 141

believe been ever found ; though fome inftances
will be hereafter mentioned, where granite con-
| tains fragments of other ftones, viz. of different
A kinds of primary fchiftus.

A To the inftances of fand involved in primary
A {chiftus, I might have added many from the
WE rocks of that order on the coaft of Berwickthire,
ity of which mention is fo often made in thefe
Th Illuftrations ; but I wifhed to draw the evi-
Mi dence from thofe rocks that are moft unequivo-
‘li cally primary, and to which the Wernerian di-
m tinction of intermediate could not poflibly be
TE applied.

inte If any one affert, as M. de Luc has done,
Mi that fand is a chemical depofite, a certain mode
eh of cryftallization which quartz fometimes af-
fumes, let him draw the line which {eparates fand
.@ from gravel ; and let him explain why quartz, in
ol the form of fand, is not found in mineral veins,
w in granite, nor in bafaltes, that is, in none of the
fituations where the appearances of cryftalliza-

i tion are moft general and beft afcertained.
w f

! | Nore v. § 10.
T Tranfportation of the materials of the firata.
‘=
y Pe. 1 She—Lhe great tranf{portation or travelling of

the materials of the ftrata, fuppofed by Dr Hut-

ton,

i72 ILLUSTRATIONS OF THE
ton, has been treated as abfurd by fome of hig
opponents, particularly De Luc and Kirwan,
Thefe philofophers feem not to have obferved,
that their own fyftem, and indeed every fyheni
which derives the fecondary ftrata from the
primary, involves a tranfportation of materials,
hardly lefs than is fuppofed in the Huttonian
theory, and a degradation of the primeval
mountains, in many inftances much greater,
To form fome notion of this degradation, it muft
be recollected, that the primeval mountains,
which furnifhed the materials of the fecondary
{trata in the plains, cannot have ftood in the
place now occupied by thefe plains. This is
obvious ; and therefore we muft neceflarily res
gard the fecondary ftrata as derived from the
primitive mountains which are the heareft to
them, and of which a part ftill remains. This
part is fufficient to define the bafe of the original
mountains; and the quantity of the fecondary
ftrata which furround them may help us to make
fome eftimate of their height. Let us take, for
inftance, the extenfive tract of fecondary country
about Newcaftle, where coal mines have been
funk through a fucceflion of fecondary ftrata, to
the depth of more than a thoufand feet. This
fecondary country may be confidered as com-
prehending almoft the whole of the counties of
Northumberland and Durham, and probably as
extending

j HUTTONIAN THEORY. 173

extending very far under the part of the Ger-
man Ocean which wathes their coafts; and the
whole ftrata compofing it muft be derived, on
the hypothefis we are now confidering, from
the Cheviot Hills, on one fide, and from thofe
in the high parts of Weftmoreland and Cum-
berland on the other, comprehending the Alfton-
Moor Hills, and the large group of primary
mountains, fo well known from the fublime and
romantic fcenery of the Lakes. Now, the moun-
tains which ftood on this bafe, had not only to
fupply the materials for the tract already men-
tioned, on the eaft, but had alfo their contingent
to furnifh to the plains on the weft and north ;
the Cheviots to Roxburghfhire and Berwick-
fhire; the Northumberland mountains to the
coal ftrata about Whitehaven, and along the
fea-coaft to Lancafhire. On the whole, we fhall
not exceed the truth, if we fuppofe, that the fe-
condary ftrata, at the feet of the above moun-
tains, are fix or feven times more extenfive than
the bafe of the mountainous tract. If then we
take the medium depth of thefe fecondary ftra-
ta to be one thoufand feet, it is evident, that the
mafs of {tone which compofes them, if it were
placed on the fame bafe with the primitive
mountains, would reach to the height of fix
thoufand feet. This is fuppofing the mafs to
preferve the breadth of its bafe uniformly to
: the

174 ILLUSTRATIONS OF THE

the fummit; but if it be {uppofed to taper, aş
mountains ufually do, we muft multiply this fix
thoufand by three, in order to have the height of
thefe primeval mountains, which, therefore, were
originally elevated not lefs than eighteen thou-
fand feet: in height, therefore, they once rivalled
the Cordelieras, and are now but poorly reprefent.
ed by the hills of Skidaw and Helvellyn. It were
ealy to fhew, that this eftimate is ftill below the
refult that ftri€tly follows from the Neptunian
hypothefis ; but it is unneceflary to proceed fur-
ther, than to prove, that the principle of the de-
gradation of mountains, is involved in that hypo-
thefis to an exceffive and improbable degree; and
that the fupporters of it, have either been guilty
of the inconfiftency of refufing to Dr Hutton the
moderate ufe of a principle, which they them-
felves employ in its utmoft extent, or of not
having fufficiently adverted to the confequences
of their own fyftem. ;
156. The formation of fecondary ftrata from
the degradation of the contiguous mountains, on
clofe examination, is fubje@ to many other dif-
ficulties of the fame kind. Mountains of fecon-
dary ftrata, and nearly horizontal, are found in
this ifland of the height of three thoufand feet.
Such are Ingleborough, Wharnfide, and perhaps
fome others on the weft of Yorkthire. The
wholg

m

me

n a

HUTTONIAN THEORY. 175

whole chain, indeed, for fecondary mountains,
js of great elevation. The ftrata are of lime-
ftone, and of a very coarfe-grained fandftone,
alternating with it. No mountains can more
clearly point out, that the ftrata of which they »
confit were once continued quite acrofs the val-
lies which now feparate them; and hence, if
the materials of thofe ftrata were indeed fur-
nifhed from any contiguous primitive moun-
tains, the latter muft have been, out of all pro-
portion, higher than any mountains now in |
Britain. | ae

157. Thus, a great degradation of the primi-
tive mountains, and of courfe a great travelling
of their materials, is proved to make a neceflary
part of the Neptunian theory. The extent of
this travelling or tranfportation may be render-
ed more evident, if we apply a fimilar mode
of reafoning to larger portions of the globe.
The north-weft of Europe furnifhes us an in-
ftance of a very extenfive trat of fecondary
country, comprehending the greater part of Bri-
tain, the whole of Flanders and Holland, part
of Germany, the northern provinces of France,
and probably the bed of the German Ocean, at
leaft for a great extent. Within this circle al-
moft all is fecondary, and on the fides of it all
round are placed ridges or groups of primitive
mountains, namely, the mountains of Auvergne,

at

276 ILLUSTRATIONS OF THE

at leaft in part, and going round by the eaft,
the Alps, the Vofges, the Hartz, the Highlands
and Weftern Iflands of Scotland, the hilly coup.
tries of Cumberland, Wales and Cornwall, Thi,
zone of primitive mountains, on the fuppo.
fition of the Neptunifts, muft have rifen up ip
the form of iflands in the great ocean, that orj-
ginally covered the earth, forming a kind of
circular Archipelago, including in its bofom
a fea, which was from feven to five hundred
miles in diameter. Over the whole of this
extent, the detritus of the above mountains mut
have been carried, in order to form the flat in.
terjacent countries which are now expofed to our
view. Such then, even on their own fuppofi-
tion, is the extent to which the Neptunifts muft
admit that the materials of the primeval moun-
tains were tranfported by the ocean.

158. This tranfportation of materials, may
not be fo great as that which is involved in Dr
Hutton’s theory, but is fuch as fhould make the
enemies of his fyftem confider, how nearly the
principles they muff introduce, agree with
thofe that they would rejeQ. This is one fact
out of many, which fhews, that there is at
prefent a much nearer agreement between,
the fyftems of geology, than between their au-
thors.
= 159. To

ay

——

HUTTONIAN THEORY. 1%

é

159. To thefe fats, demonftrating the great
tran{portation of foffils in fome former condi-
tions of the globe, we may add another, re-
cognifed by all mineralogifts. The animal ex-
uvie contained in limeftone and marble, are
often known to belong to feas, extremely re-
mote from the countries where they are now
found. In the chalk-beds of England, in the
limeftones of France, a great proportion of the
petrifactions belong to the tropical feas, and ap-
pear to have been brought from the vicinity of
the equator. Buffon obferves, that of the fotlil
Shells found in France, it has been difputed,
whether the foreign are not more numerous than
the native; and, though he is himfelf of opinion
that they are not, it is evident that they muft
bear a confiderable proportion to the whole *.
In the petrifa@iions of Monte Bolca, near Ve-
rona, where the impreflions of fifh are preferved
between the laminz of a calcareous ichiftus, one
hundred and five different fpecies have been enu-
merated, of whichthirty-nine are from the Afiatic
feas, three from the African, eighteen from thofe

of South, and eleven from thofe of North Ame-

rica +. Similar obfervations have been made
on the marine plants, and the impreffions of ve-

- getables, found in rocks, in different parts of

M Europe.

* Buffon, Théorie de la Terre, art. 8.

t Sautlure, Voyages aux Alpes, tom, ili. § 1535.

178 ILLUSTRATIONS OF THE

Europe. At St Chaumont, near Lyons, is found
an argillaceous fchiftus, covering a bed of coal,
every lamina of which is marked with the im-
preffions of the ftem, leaf, or other part of fome
plant; and it happens, fays M. FONTENELLE,
by an unaccountable deftination of nature, that

not one of thefe plants is a native of France, .

They are all ferns of different fpecies, peculiar
to the Eaft Indies, or the warmer climates of
America. Here alfo was found the fruit of a
tree, which grows only on the coafts of Malabar
and Coromandel *.

The fame holds of the bodies of amphibious
animals which now make a part of the foffil
kingdom. The head and the bones of croco-
diles have been found in the ifland of Shepey,
at the mouth of the Thames; and the remains

of an animal of the fame fpecies, but of a va- -

riety now peculiar to the Ganges, have been
difcovered in the alum rocks on the coaft of York-
fhire +. Thefe proofs of the tranfportation of

materials

* Mém. de l’Acad. des Sciences, 1718, p. 3. and 2873
and 1721, p. 89, &c.

t Phil. Tranf. vol.1, p.688. Camper denies that the
remains here mentioned belong to the crocodile, or any
amphibious animal, and refers them to the balena. He
paffes the fame judgment on thofe foflil bones from St Pe-
ter’s Mount, near Maeftrich, which have been fuppofed to

belong

EE ne ee ETT

¥

—— rl i
| HUTTONIAN THEORY. 179 ?
N materials by the fea, have the advantage of in-

5 = yolving nothing hypothetical, and of being equal-
\ lyaddreffed to the geologifts of every perfuafion.

h On this fubje& I cannot help obferving, that
W the accurate comparifon of the animal exuviæ
Hk of the mineral kingdom, with their living arche-
a types, is not merely a curious inquiry, but is
et one that may lead to important confequences,
ti = concerning the nature and diredtion of the for-
ti = œe which have changed, and are continually

alh changing, the furface of the earth.
| 160. Thefe remarks I have thought it proper
im toadd to the proofs of the compofition of the `

fii prefent from former ftrata, in order to fhew, that
w the great tranfportation of materials involved in
ep ‘that fuppofition, is not only conformable to the

mi hypothefis of the Neptunifts concerning the fe-
aw condary firata, but is alfo proved by the moft
w dire& evidence, independently of all hypothefis.
a All this reafoning regards the ancient flate of
on M2 the’
wi

—

belong to the crocodile ; he looks on them as belonging to
it whales, though of an unknown fpecies. In this Mount, fo
famous for its petrifactions, he finds many fpecimens of
J bones, which he thinks belong to the turtle. Phil. Tranf.
wi vol, Ixxvi. p.443. The opinion of an author, fo well
oth {killed in comparative anatomy, muft be regarded as of
J great weight : if it takes from our argument in one part,
gf i it adds to it in another, and the acquifition of the turtle
ji makes up abundantly -for-the lofs-of the crocodile.
A

180 ILLUSTRATIONS OF THE

the globe. Whether fuch a travelling of ftony
bodies makes a part of the fyftem now actually
carrying on, will be confidered in another
place *,

Note vi. § 13.
Mr Kirwan’s notion of precipitation.

161. The Neptunift who has provided the
means of diffolving the materials of the ftrata,
has only performed half his work, and muft find
it a tafk of equal difficulty to force this power-
ful menftruum to part with its folution. Mr
Kirwan, aware in fome degree of this diffi-
culty, has attempted to obviate it in a very fin-
gular way. Firft, he afcribes the folution of all
fubftances in water, or, in what he calls the
chaotic fluid, to their being finely pulverifed,
or created in a ftate of the moft minute divifion.
‘Next, as to the depofition, the folvent being, as
he acknowledges, very infuflicient in quantity,
the precipitation took place, (he fays), on that
account the more rapidly.

If he means by this to fay, that a precipitation
without folution would take place the fooner
the more inadequate the menftruum was to dif-
folve the whole, the propofition may be true;

but

* See Nore XIX.

HUTTONIAN THEORY. 181

but will be of no ufe to explain the cryftalliza-
tion of minerals, (the very object he has in view),
becaufe to cryftallization, it is not a bare fubfi-
dence of particles fufpended in a fluid, but it is
a paflage from chemical folution to non-folu-
tion, or infolubility, that is required.

If, on the other hand, he means to fay, that the
folution actually took place more quickly, and
was more immediately followed by precipitation,
becaufe the quantity of the menftruum was in-
fufficient, this is to affert, that the weaker the
caufe, the more inftantaneous will be its effe@.

Of two propofitions, the one of which is nu-
gatory, and the other abfurd, it is not material to
anquire which the author had in view.

Nore vil. § 16.

Compreffion in the mineral regions.

462. It is worthy of remark, that the effects
afcribed to compreffion in the Huttonian Theo-
ry, very much refemble thofe which Sir Isaac
Newton fuppofes to be produced in the fun and
the fixed flars by that fame caufe. “ Are not,”
fays he, “ the fun and fixed ftars great earths,
vehemently hot, whofe heat is conferved by the
greatnefs of the bodies, and the mutual action

M 3 7 and

182 ILLUSTRATIONS OF THE

and reaction between them, and the light Which
they emit; and whofe parts are kept from fu-
ming away, not only by their fixity, buit alfo by the
vaft weight and denfity of the atmofpberes incim
bent upon them, and very firongly compreffing
them*,””

163. The fatt, of water boiling at a lower
temperature under a lefs compreffion, is fafi-
cient to juftify the fuppofition, that bodiés may
be made by preffure to endure extreme heat,
without the diffipation of their parts, that is,
without evaporation or combuftion. A further
poftulatum is introduced in Dr Hutton’s theoty,
namely, that compound bodies, fuch as carbo-
nat of lime, when the compreffion prévents
their feparation, may admit of fufion, notwith-
ftanding that the fixed part may be infufible
when feparated from the volatile. This affump-
tion is fupported by the analogical fact of the
fufion of the carbonat of barytes, as mentioned
in the text.

164. In a region where the action of heat was
accompanied with fach compreffion as is here
fuppofed, there could be no fire, properly fo
called, and no combuiftion: this is admitted by
Dr Hutton, and it is therefore a fallacious ar-
gument which is brought againft his theory,
from the impoffibility of fire being maintained

in

amaA
<a

# Newton’s Optics, Query 11,

HUTTONIAN THEORY. 183

iy in the bowels of the earth. This impoflibility
hh is precifely what he fuppofes ; and yet Mr Kir-

hy wan’s arguments are directed, not againft the
Mn exiftence of heat in the interior of the earth,
thy but againft the exiftence of burning and inflam-
7) mation.

After taking notice *, that Sauffure had fuc-
ceeded, though with extreme difficulty, in melt-
ing a particle of limeftone, fo {mall as to be vi-
fible only with a microfcope, ‘ what (adds he)
muft have been the heat neceffary to melt whole
mountains of this matter? Judging by all that
we at prefent know of heat, fuch a high degree
could only be produced by the pureft air, acting
on an enormous quantity of combuftible matter.
Now, Exrman obferved, that the combuttion
of two hundred and eighty cubic inches of air,
aĝing on charcoal, was not able to effect the
fufion of one grain of Carrara marble; from
whence it is apparent, that all the air in the at-
mofphere, nor in ten atmofpheres, would not
melt a fingle mountain of this fubftance, of any
extent, even if there were a fufficient quantity
of inflammable matter for it to a& upon. Judg-
ing alfo of fubterraneous heat by what we know
of that of volcanoes, no fuch heat exifts: the
higheft they in general produce, is that requi-
fite for the fufion of the volcanic glafs called
M 4 obfidran,

* Geol. Effays, P. 453.

184 ILLUSTRATIONS OF THE

obfidian, which Sauffure found not to exceed
115° of Wedgewood; but bafaltine, which re.
quires 140° of Wedgewood, is never melted in
the lavas of Ætna. How little capable, then,
would volcanic heat be to effec the fufion of
Carrara marble, which, according to the fame
excellent author, would require a heat of up-
wards of 6300° of Wedgewood, if this pyrome.
ter could extend fo far? And in what circum. `
ftances does Dr Hutton fuppofe this aftonifhing
heat to have exifted, and even fill to exif,
under the ocean, in the bowels of the earth,
where neither a fufficient quantity of pure air,
nor of. combuftible matter, capable of fach
mighty effects, can, with any appearance of pro-
bability, be fuppofed to exit; and, without
thefe, fuch degrees of heat cannot even be ima,
gined, without flying into the region of chime:
ras.”’

165. Now, this reafoning is not applicable
to Dr Hutton’s hy pothefis of fubterraneous heat,
becaufe it is grounded on experiments, where
that very feparation of the volatile and fixed
parts takes place, which is excluded in that
hypothefis. When limeftone or marble is ex-
pofed to fuch heat as is here mentioned, or
even to heat of a degree vaftly inferior, the
carbonic gas is expelled, and the body is redu-
ced to pure lime; from the refraCtory nature
ef which, as we learn from the fact relative

to

re

HUTTONIAN THEORY. 185

to barytes, mentioned above, no conclufion can

be drawn as to the infufibility of the fame fub-

ftance, when combined with the carbonic gas.
The Carrara marble may require a heat of
6300° of Wedgewood, to melt it in the open
air, where the carbonic gas efcapes from it; but
under fuch a preffure as would retain this gas,
it cannot be inferred, that it might not melt
with the heat of a glafs-houfe furnace. In like
manner, it may. be true, that two hundred
and eighty cubic inches of air, acting on
charcoal, cannot effect the fufion of one grain
of this marble, after its fixed air is driven off
from it; but we cannot from thence draw any
inference, applicable to a cafe where the carbo-
nic gas is retained, and where the action EF heat
is independent of atmofpheric air.

Nothing, therefore, can be more inconclufive
than this reafoning, as it proceeds on the fuppo-
fition, that Dr Hutton’s fyftem admits propofi-
tions, which in fact it exprefsly denies.

166. Of the production and maintenance of
heat, in circumftances fo different from thofe of
ordinary experience, we can hardly be expected
to give any explanation ; but we are not entitled,
merely on that account, to doubt of the exiftence
of fuch heat. Mr Kirwan thinks otherwife:
“ Judging,” hefays, “ from all we at prefent know
of heat, fuch a high degree of it, (as will melt
limeftone), could only be produced k the pu-

reft

186 ILLUSTRATIONS OF THE

reft air, acting on an enormous quantity of com.
buftible matter. Without thefe, fuch degrees
of heat cannot even be imagined, without fly-
ing into the region of chimeras *.” :
Now, in the firt place, the high degree of
temperature which is here underttood, is pro.
bably not neceflary to the purpofes of minerali.
zation, as has juft been fhewn; and, in the fe-
cond place, it is not FIRE, in the ufual fenfe of
the word, but uzar, which is required for that
purpofe ; and there is nothing chimerical in fup-
‘pofing, that nature has the means of producing
heat, even in a very great degree, without the
afliftance of fuel or of vital air. Fri@ion isa
fource of heat, unlimited, for what we know, in
its extent, and fo perhaps are other operations,
both chemical and mechanical; nor are either
combuftible fubftances, or vital air, concerned
in the heat thus produced. So alfo the heat of
the fun’s rays in the focus of a burning glafs,
the moft intenfe that is known, is independent
of the fubftances juft mentioned ; and, though
that heat certainly could not calcine a metal,
nor even burn a piece of wood, without oxyge-
nous gas, it would doubtlefs produce as high a
temperature in the ablence as in the prefence

of that gas.
It

ad

* Geol. Effays, p. 454.

ee ee a A E S S

(a maa Pi ac
R;
a -

HUTTONIAN THEORY. 187

It is true, that it is not by the folar rays that
W fubterraneous heat is produced ; but ftill, from
= this inftance, we fee, that there'is no incongrul-
a ty in fuppofing the production of heat to be in-
dependent of combuftible bodies, and of vital air.
lt) We are indeed, in all cafes, ftrangers to the ori-

tej gin of heat: philofophers difpute, at this mo-
th ment, concerning the fource of that which is
a produced by burning ; and much more are they
7 at a lofs to determine, what upholds the light
' and heat of the great luminary, which animates
tij all nature by its influence. If we would form
a any opinion on this fubje&, we fhall do well

to attend to the fuggeftions of that great philo-
MI fopher, who was hardly lefs diftinguifhed from
J others by his doubts and conjectures, than by
his moft rigorous and profound inveftigations.
i ~~“ May not great, denfe, and fixed bodies, when
heated beyond a certain degree, emit light fo
copioufly, as, by the emiffion and reaction of
its light, and the refle@ions and refractions of
a its rays within its pores, to grow ftill hotter, till
tb it comes to a certain period of heat, fuch as is
si that ofthe fun? And, are not the fun and fix-
| ed ftars great earths, vehemently hot, whofe heat
wl is conferved by the greatnefs of the bodies, and
_ the mutual action and re-aétion between them
and the light which they emit *?”
> 167. Some

a

——

* Newton's Optics, ubi /upra.

1358 ILLUSTRATIONS OF THE

167. Some recent experiments, feem to make
the fuggeftions in this query applicable to an
opaque body like the earth, as well as to lumi-

nous bodies, fuch as the fun and fixed ftars,

The radiation of heat, where there is no light,

was firft rendered probable by the experiments —

of M. Picter of Geneva * ; and the only ob-
jeCtions to which the conclufions from thofe ex-
periments feemed liable, are removed by the
late very important difcoveries of Dr Her.
SCHEL}. From thefe it appears, that heat is
capable of refraction and refleGion, as well as
light, fo that it is not abfurd to fuppofe, that
the heat of great, denfe, and fixed bodies, may be
conferved by the greaine/s of the bodies, and the
mutual action and reaction between them and the
beat which they emit.

The exiftence of fubterraneous heat is ftill
further rendered probable from the refearches
of Marran, which tend to fhew, that there is
another fource of terreftrial heat befides the in-
fluence of the folar rays f.

Whatever be the truth with regard to thefe
conjectures, it is certain, that the firt and ori-
ginal fource of heat is independent of burning.
Burning 1s an effect of the concentration of heat;

and

* Effai fur le Feu.
+ Phil. Tranf. 1800. p. .84.
į Mém. de Acad, des Sciences, 1765, p. 143-

HUTTONIAN THEORY. 189

by and though, by a certain reaction, it has the
“hy power of continuing and augmenting that heat,
Uy it never can be regarded as its primary and ma-
dj, terial caufe. When, therefore, we fuppofe a
Ol, fource of heat, independent of fire and of burn-
tity - ing, we fuppofe what certainly exifts in nature,
tl; though we are not informed of the manner of
ley its exiftence, nor of its place, otherwife than
by from confidering the phenomena of the mineral
Th kingdom.

168. Laftly, we are not entitled, according

’ _ to any rules of philofophical inveftigation, to re-
ei jet a principle, to which we are fairly led by
i i an induGion from fas, merely becaufe we can-
if not give a fatisfactory explanation of it. It
| would be a very unfound view of phyfical

fcience, which would induce one to deny the
principle of gravitation, though he cannot ex-
plain it, or even though the admiffion of it
reduces him to great metaphyfical difficulties.
If indeed a downright abfurdity, or inconfiften-
cy with known and eftablifhed facts, be invol-
ved in any principle, it ought not to be ad-
_ mitted, however it may feem calculated to ex-
plain other appearanes. If, for inftance, Dr
Hutton held, that combuftion was carried on in
a region where there was no vital air, we fhould
have faid, that he admitted an abfurdity, and
that a theory founded on fuch poffulata, was
worfe than chimerical, But, if the only thing

imputable

190 ILLUSTRATIONS OF THE

imputable to him is, that, being led by induc.
tion to admit the fufion of mineral fubftances in
the bowels of the earth, he has affumed the ex.
iftence of fuch heat as was fufficient for this fy.
fion, though he is unable to affign the caufe of
it, I believe it will be found, that his fyitem
only fhares in an imperfection, which is com.
mon to all phyfical theories, and which the ut.
moft improvement of fcience will never com.
pletely remove.

169. Thus, then, we are led, it mutt be allow.
ed, into the region of hypothefis and conjecture,
but by no means into that of chimeras. Indeed,
the reproach of flying into the latter region,
may be faid to come but ill from one, who has
trode fo often the crude conjiftence of the chaos,
and who delights to dwell beyond the bounda-
ries of nature. By fojourning there long, it is
not impoffible that the eye may become fo ac-
cuftomed to fantaftic forms, that the figures and
proportions of nature fhall appear to it deform-
ed and monftrous.

Norte VIIL § 24.
Sparry firucture of calcareous petrifactions.

170. When the fhells and corals in limeftone
are quoted by mineralogifts, it is not always
confidered

HUTTONIAN THEORY. igi

confidered in what ftate they are found. In

general, they have a {parry ftructure, very dif-
ferent from that of the original fhell or coral,
of which, however, they retain the figure with
wonderful exactnefs, though probably fome-
times altered in fize. Though fparry, they are
often foliated, and preferve their animal, in con-
junction with their mineral, texture. Now, this
cryftallization is a mark of fome operation,
quite different from any that can be afcribed
to the water in which thefe bodies had their
origin, and by which they were brought into
their place. They were impervious to wa-
ter; and it cannot be faid that their fparry
ftruture has been derived from the percolation
of that fluid, carrying new calcareous matter
into their pores. We can account for the
change produced in them, I think, only by
fuppofing them to have been foftened by heat,
fo as to permit their parts to arrange them-
felves anew, and to aflume the characteriltic
organization of mineral fubftances.

All fhells have not the change effected on
them that is here referred to; thofe in chalk,
for inftance, retain very much their original
form in all refpe&s. This is what we might
expect from the very different degree of inten-
fity, with which the mineralizing caufe has
acted on chalk, and on limeftone or marble. In
general, it is in the hardeft and moft confolida-

ted

192 ILLUSTRATIONS OF THË

ted limeftone, that the marine objects are mof
completely changed into fpar.

It would be exceedingly interefting to ex.
amine, whether any of the phofphoric acid re.
mains united to fhells of either of thefe kinds,
We might moft readily expeé it to be united,
in a certain degree, to the fhells that are leat
mineralized.

This experiment would enable us alfo to ap-
preciate the force of Mr Kirwan’s argument
againft the finer marbles, fuch as the Carrara,

containing fhells*. This argument proceeds on _

an experiment, mentioned in the Turin Memoirs
for 1789, from which it appears, that no phof-
phoric acid is found in pure limeftone; and
its abfence, Mr Kirwan fays, cannot be attribu-
ted to fufion, as phofphoric acid is indeftrudible

by heat. 2 7
He calls this a demonftration ; but, in order
to entitle it to that name, it will be neceflary,
firft, to prove, that phofphoric acid exifts in
thofe limeftones which evidently coniift of fhells
in a mineralized ftate. If thefe are found with-
out phofphoric acid, it is evident that the pre-
ceding argument fails entirely. If they are found
to contain that acid, it will then no doubt afford
a probability, though not a demonftration, that
Carrara

* Geol, Effays, p. 458,

co a

l HUTTONIAN THEORY. r93

l Carrara marble does not directly originate from
hy —thellls. |
tidy, That nature has fome procefs, by which the
_ above acid is feparated from the earth of bones,
iy and probably alfo from the earth of fhells, is
_ evident from the ftate in which the bones are

found in the caves of Bayreuth. Thofe that are
the moft recent, and leaft petrified, contain moft
of the phofphoric acid. Where the petrifaction
has proceeded far, that acid is not found.

171. Among many of the ftrata, fuch a fluidi-
ty has prevailed, as to enable fome of thé fub-
ftances included in them to cryftallize. Calca-
reous fpar and filiceous cryftals are often found
in ftratified rocks, forming veins of fecretion, or
lining clofe cavities, included on all fides by the
uncryftallized rock. In the inftances of gneifs,
7 and many fpecies of marble, almoft the whole
a matter of the ftratum is cryftallized. This
iy union of a ftratified and cryftallized ftru€ture in
_ the fame fubftance, has a great affinity to that
it! §—_ union of the cryftallized with the organic ftruc-
il turcof hells and corals which has juft been
pi mentioned; and both are doubtlefs to be refer-
0 _ red to the fame caufe.

a
ae

N Nore

194 ILLUSTRATIONS OF THE |

Nove 1x. § 31.
Petroleum, Se.

172. According to the theory of coal laid

down above, its two chief materials, charcoal

and bitumen, being furnifhed by the vegetable
and animal kingdoms, both of the land and of
the fea, have formed with one another a new
bination, by the action of fubterraneous
heat; but have alfo, in fome cafes, been fepa-
rated by that fame action, where the degree of
compreflion neceflary for their union, happened
to be wanting. The carbonic part, when thus
feparated from the bituminous, forms an infufi-
ble coal, which burns without flame: the bitu-
minous part, when feparated from the carbonic,
is found in the various ftates of naphtha, petro-

leum, afphaltes, and jet. |
The great refemblance of infufible or blind
coal, to the refiduum obtained by the diftilla-
tion of bituminous coal; and again, the coin-
cidence of the bitumens juft named, with the
volatile part, or the matter brought over by
fuch diftillation, are ftrong arguments in fa-
vour of this theory. The other fads in the na-
tural hiftory of coal, ferve to confirm the fame
conclufion; but it muĝ be confefled, that what
we

—

t

HUTTONIAN THEORY. 1905

-we know of the pure bitumens, except the cir-
cumftance juft mentioned, is of a more ambigu-
ous nature, and may be reconciled with different
theories. The drops of petroleum contained
within the cavities of the limeftone, mentioned
at § 31., are however ftrong facts in confirmation
of Dr Hutton’s opinions, and they are furnifhed
by the fubftances purely bituminous.. A careful

examination would probably make us acquainted _
with others of the fame kind, for limeftone is very
often the matrix in which petroleum and afphal-
tes are contained. The greateft mine of afphal-
tes in Europe, that in the Val de Travers, in
the territory of Neufchâtel, is in limeftone, from
which, though it in fome places exudes, it is in
general extracted by the application of heat.
The ftrata for feveral leagues are impregnated
with bitumen; and, if examined with atten-
tion, would probably afford fpecimens fimilar

to thofe which have juft been mentioned.

173. It is a general remark, that, where pe-

troleum is found, on digging deeper, they come

to afphaltes; and, at a depth ftill greater, they
difcover coal. This probably does not hold in-
variably ; but it is certain, that moft of the
fountains of petroleum are in the neighbourhood
of coal ftrata. Petroleum and afphaltes are
found in great abundance in Alface, in a bed of
fand, between two beds of clay or argillaceous

N 2, {chiftus,

196 ILLUSTRATIONS OF THE

{chiftus, and the fame country alfo affords coal ¥,
This is true likewife of the foflil-pitch of .Coal-
Brookdale ; and of the petroleum found in St $
Katharine’s well, near Edinburgh. Auvergne +
contains abundance of foflil-pitch, which exudes,
in the warm feafon, from a rock impregnated
with it through its whole mafs. There are
-alfo coal ftrata in the fame country, not far
diftant.

A very fatisfactory obfervation relating to
this fubject, has lately been communicated from
a country, with whofe natural hiftory we were
till of late entirely unacquainted. In the Bur-
mha empire, petroleum is dug up in an argilla-
ceous earth, from the depth of feventy cubits.
‘This argillaceous earth, or fchiftus, lies under a
bed of freeftone ; and under all, about one hun-
dred and thirty cubits from the furface, is a bed
of coal f. l

174. In the petroleum lake of the Ifland of
Trinidad, defcribed Phil. Tranf. 1789, the pe-
troleum evidently exudes from the rock, and is
collected in a variety of fprings in the bottom,

after which it hardens, and acquires the confift-
ency

* Encyclopédie, mot, d/pdalte.
¥
+ Voyage en Auvergne, par Legrand, tom. i. p, 351+

t Afiatic Refearches, vol. vi. art. 6. p. 130.

HUTTONIAN THEORY. 197

q encyof pitch. The manner, therefore, in which

a eT

~~ 4 ue it
a SE ee

Se Se

petroleum exifts in the ftrata, is very confiftent
‘with the idea of its having been introduced in
the form of a hot vapour.

Even amber appears to have fome relation to
coal. It is found in the unconfolidated earth in
Pruffia and Pomerania; but I am not fure whe-
ther this earth is travelled or not. In the fame
earth where the amber is found, there is often a
mixture of coaly matter, which burns in the
fire; it is apparently fibrous, and has been con-
fidered as a kind of foffil-wood *.

Thefe citcumftances make out a connection
between the purer bitumens and ordinary coal ;
but do not, it muft be acknowledged, eftablith
any thing with refpect to the more immediate
relation, f{uppofed in this theory to exift between
‘them and blind-coal. It is probable, indeed,
that, to difcover any facts of that kind, the na-
tural hiftory of both fubftances muft be more
carefully examined ; the natural hiftory of blind-
coal, in particular, has hitherto been but little
attended to.

175. A fad is mentioned by Mr Kirwan, which
muft not be regarded as lefs valuable for being
adverfe to this theory. It is, that neither pe-
troleum, nor any foffil bitumen, is found in the

_ Vicinity of the Kilkenny coal, as might be ex-

N 3 pected,

* Buffon, Hitt, Nat. des Mineraux, tom. ii. p. 5.

198 ILLUSTRATIONS OF THE

pected, if that coal was deprived of its bitumi-
nous part by fubterraneous diftillation *. This,
however, admits of explanation. ‘Though a ge. |
neral connection, on the above hypothefis, might
be expected between bitumens and infufible
coal, we cannot look for it in every inftance,
The heat which drove off the bitumen from
one part of a ftratum of coal, may only have
forced it to a colder part of the fame ftratum;
and thus, in feparating it from one portion of
carbonic matter, may have united it to another,
Blind-coal may therefore be found where no
bitumen has been actually extricated. In like
manner, bitumen may have been feparated, where
the coal was not reduced to the ftate of coak, as |
a part of the bitumen only may have been driven
off, and enough left to prevent the coal from
becoming abfolutely infufible.

It fhould be confidered too, if the bitumen
was really feparated, and forced, in the ftate of
vapour, into fome argillaceous or limeftone ftras
tum, that this ftratum may have been wafted and
worn away long ago, fo that the bitumen it con-
tained may have entirely difappeared. It does
not therefore neceffarily follow, that, wherever
we find blind-coal, there alfo we fhould difcover

fome of the purer bitumens.
| Note

*. Geol, Effays, pP. 473>

HUTTONIAN THEORY. 199
hi
K
tn) : 3S
tih Nore x. § 37.
B. | a
am The height above the level of the fea at which the
fy marks of aqueous depofition are now found,
Da
i 176. We have two methods of determining
the the minimum of the change which has happen-
a ed to the relative level of the fea and -land ;
T or for fixing a limit, which the true quantity
i of that change muft neceflarily exceed. The
me one is, by obferving to what height the regular
i ftratification of mountains reaches above the
i prefent level of the fea; the other is, by deter-
i mining the greateft height above that level, at
which the remains of marine animals are now

found. Of thefe two criterions, the firft feems
preferable, as the fa& on which it proceeds is
moft general, and leaft fubject to be affected by
“i accidental caufes, or fuch as have operated fince
coh the formation of the rocks.. The refults of both,
however, if we are careful to felect the extreme
cafes, agree more nearly than could have been
expected. :

177. The mountain Rofa, in the Alps, is en-
WW —_‘tirely of ftratified rocks, very regularly difpofed,
A N4 and

too ILLUSTRATIONS OF THE

and nearly horizontal *. The higheft fummit
of this mountain is, by Sauffure’s meafurement,
2430 toifes, or. 14739 Englifh feet, above the
level of the fea, or lower than the top of Mont
Blanc only by 20 toifes, or 128 feet +. This is,
I believe, the higheft point on the earth’s fur-
face, at which the marks of regular ftratifica-
tion are certainly known to exift; for though,
by the account of the fame excellent mineralo-
gift, Mont Blanc itfelf is ftratified, yet, as the `
rock is granite, the ftratification vertical, and
fomewhat ambiguous, it is much lefs proper
than Mont Rofa for afcertaining the limit in
queftion.

178. Again, in the new continent, we have
an inftance of fhells contained in a rock, not
much lower than the fummit of Mont Rofa.
This is one defcribed by Don Uxtoa; near the
quickfilver mine of Guanca-Velica, in Peru.
The height at which a fpecimen of thefe fhells,
given by Ulloa to M. le Gentii, was found,
Was 22224 toifes, or 14190 feet Englifh, above
the level of the fea f. This height agrees with
the preceding, within 549 feet, a quantity com-
paratively fmall.

179. The

* Voyages aux Alpes, tom. iv. § 2138.

t lbid. § 2135.

t See Hit. Acad. des Sciences, 1770. Phyf, Géne-
rale, No. 7.

HUTTONIAN THEORY. 205”

179. The laft of the facts juft mentioned is
curioufly commented on by Mr Kirwan. As he
has proved, he fays, that the mountains higher
than 8500 feet. were-all formed before the crea-
tion of fifth, it follows, that the fhells found at
Guanca-Velica, muft have been carried there by
the deluge*. Now, without objecting to the
proof here referred to, (though it feems very open
to objection), it is fufficient to remark, that, if the

~ fhells at Guanca-Velica were carried there by the

deluge, or any other caufe that operated after the
formation of the rock of which the mountain
confifts, they can make no part of that rock, but
muft lie, like other adventitious foffils, loofe and

_ detached on the furface, or at moft externally

agglutinated to the flone. This, however, is
certainly not the fa&t ; for, in the account juft
quoted, we read, that Don Ulloa told M. le Gen-
til, © qu’il avoit détaché ces coquilles d’un banc
fort épais.” This feems plainly to indicate,
that the fhells were included in a bed of rock.
But, granting that the expreffion is a little
ambiguous, on turning to the Mémoires Phi-

lofophiques of the fame author, the difficulty is

completely removed, and it is made evident, that
thefe fhells are in fa@ integrant parts of the
rock, ‘* On voit dans ces montagnes-la, (about

Guanca-

“4 Geol. Elay: P- 54,

202 ILLUSTRATIONS OF THE

Guanca-Velica, and particularly at that in which
is the quickfilver mine), des coquilles entières,
petrifiées et enfermées au milieu de la roche,
que les eaux de pluie mettent à decouvert. Ces
coquilles font corps avec la pierre ; mais malgré
cela, on remarque que la partie qui fut coquille,
fe diftingue par la couleur, la ftru@ure, la qua-
lité de la matière de tout autre corps pierreux
qui l’enferme, et du maffif qui s’eft fixé entre
les deux ecailles *,” &c. He goes on to fay,
that one can diftinguifh marks of thefe fhells

having been worn, before they were included in —

the ftone. |
180. Thus it appears, that whatever proof
any foflil-fhell affords, that the rock in which
it is found was formed under the fea, the
fame is afforded by the foffil-thells of Guan-
ca-Velica ; and we are, therefore, perfectly en-
titled to conclude, that the relative level of
the fea and land has changed, fince the forma-
tion of the latter, by more than 14000 feet,
The height affumed in § 37. is therefore much
under the truth; and the water, for which the
Neptunifts muft provide room in fubterraneous
caverns, might very well have been ftated at
more

duane

* Mém, Philofophiques de Don Ulloa, Difcours xvi»
voli. p. 364.

as

| HUTTONIAN THEORY. 203

ti, more than a five-hundredth part of the whole
mats of the earth.

Thus alfo the argument by which the Nep-
y tunifts would connect the creation of fifh with
the beginning of the fecondary mountains, falls

SF
Pade a =e a

i = entirely to the ground. Indeed, it is ftrange

w that Mr Kirwan fhould have fuppofed it- poffi-,

ble, that the fhells in queftion were loofe and

7 unconnected with the rock, and had continued
ji

fo, ever fince the deluge, in fuch elevated ground,
i | where the torrents wear and cut down the moun-
eii tains with unexampled violence, and have hol-
lowed out Quebradas fo much deeper and more
ni abrupt than the glens or vallies among other
hi mountains. He had not, I believe, feen the paf-
il fage I have quoted from Ulloa; but the circum-
W ftances did not warrant the fhells in queftion to be
yai regarded as extraneous and adventitious foffils.
| A geologift fhould have known better than to
m fuppofe this poffible. When we fee VOLTAIRE,
fi afcribing to accidental caufes the tranfportation
nu _ of thofe thells which he had been told were often
i found among the Alps, we can excufe in a Poet
@ anda Wit, that ignorance of the facts in mine-
ji ralogy, which concealed from him the ex-
we treme abfurdity of his affertion; but when a
Chemift or Mineralogift talks and reafons in the
fame manner, we cannot confider him as enti-
ff tled to the fame indulgence.

=
cS
—

Note

204 ILLUSTRATIONS OF THE

Nore x1. § 42.

Fracture and diflocation of the ftrata.

181. The greateft part of the fa&s relative to
the fracture and diflocation of the {trata, belongs
to the hiftory of veins. The inftances of flips,
where no new mineral fubftance is introduced
between the feparated rocks, are what properly
belong to this place. The frequency of thefe,
and their great extent, are well known where-
ever mines have been wrought. In fome of
them no opening is left, but the flipped ftrata
remain contiguous ; in other cafes, there is in-
troduced an-unconfolidated earth, often a clay,
which may be fuppofed to have come from
above, and very probably to have been car-
ried down by the water. In fome fuch cafes,
however, there are not wanting appearances,
which fhow the matter in the flip to have been
forced up from below, as we find it to contain
fubftances which could not have come from the
furface *. =

189%

* Unconfolidated earth contained between the fides of
a rock that has flipped, is frequent in Cornwall, and is
called a Hleukan-

HUTTONIAN THEORY. 208

182. A very remarkable fact of this kind oc-
a curred not long ago, in digging the Huddersfield
| canal in Yorkfhire ; and a very diftin@ account
of it is given in the Philofophical Tranfactions,
by the engineer who directed the work. In
carrying a tunnel into the heart of a hill, the
tit) miners came to what is called in the defcription :
a fault, throw, or break, or what we have here
EA called a hift, which was filled with /Bale fet on
Oli; edge, mixed with fofter earth, and in fome pla-
lope ces With {mall lumps of coal. The fault or
‘thi = {pace filled with thefe materials, was in general
whe about four yards broad, and lay nearly in the
me; direction of the tunnel, fo that a confiderable
ify extent of it was vifible. Befide the fhale, it
contained a rib of limeftone, about four feet
1 thick, which run parallel to the fides of the fault,
fy and about four feet from the fouthern margin
= ofit. On each fide of this rib were found balls
ak -«f limeftone, promifcuoufly fcattered, and of va-
= rious fizes, from an ounce to one hundred pounds

a fy
A f-
ts ati

=
=
ail

ie

We weight. ‘The balls, when broken, were found 2

ti _ to contain fome pyrites near their edges; they és
y were not perfeCtly globular, but flattened on the

i : j oppofite fides, and fimilar to one another *.

d At the time when the account was written, about

" _ feventy yards of the rib had been difcovered.

is @ 183. Now,

w E E

* Phil, Tranf. 1796. p. 350.

206 ILLUSTRATIONS OF THE

183. Now, it is certain, that neither this rib
of limeftone, nor the balls that accompanied it,
can have come from above, as there is no lime.
ftone within twenty miles of the place where
they were found. They muft, therefore, haye
been forced up from below, and no doubt be.
long to fome limeftone ftrata, which lie there at
a great depth under the furface. The length
of this fragment of rock, which, from the ac.
count, one muft fuppofe to have been entire,
conveys no mean idea, either of the intenfity or
regularity of the force by which it was brought
into its prefent fituation. In veins, it is not un-
common to meet with ftones that appear to have
come from a greater depth: but this is probably
the moft remarkable inftance of the fame phe-
nomenon, which has appeared in a mere flip, and
none, I think, can {peak a language lefs liable to
be mifunderftood. —

184. I {hall here mention another mark of
violent fracture, that has been obferved in rocks
of breccia or pudding-ftone, which, though not
of the fame kind with the preceding, and of a
nature quite peculiar, belongs rather to this
place than any other. In rocks of the kind,
juft mentioned, it fometimes happens, that con-
fiderable portions are feparated from one ano-
ther, as if by a mathematical plane, which had

eut right acrofs all the quartzy pebbles in its

way.

a

—_—-

. HUTTONIAN THEORY. 204
a way. None of the pebbles is drawn out of its
focket, that is, out of the cement that furrounds

= it, but is divided in two with a very fmooth and
. even fracture. The pebbles, in the inftances
ny which I have feen, were of quartz, and other

| fpecies of primary and much indurated rock.
x Lord Wess Seymour and I obferved pud-
i ding-ftone rocks, exhibiting inftances of this

_ fingular kind of fracture, near Oban, in Argyle-
‘i fhire, about three years ago. The phenomenon
ty = was then entirely new to us both; but I have
0} fince met with an inftance of the fame kind in
ott Sauffure’s laft work. As the fact is of fo par-
okl ticular,a kind, I fhall ftate it in his own words:
oii The place was on the fea-thore, near the little
town of Alaffio, between Nice and Genoa.
pi “En paffant entre ces blocs de breche, j’ad-
bk’ mirai quelques-uns d’entr’eux, d’une grandeur
| confidérable, et taillés en cubes, avec la plus
atk parfaite régularité. Il y avoit ceci de remar-
i quable, c’eft que l’action de la pefanteur, qui avoit
hi taillé ces cubes en rompant leurs couches, avoit
ji coupé tous les cailloux des breches à fleur de la
»# furfage de la pierre, aufi nettement que fi c’etit
yw. été une maffe molle qu’on efit tranchée verti-
of calement avec un rafoir, Cependant parmi ces
g cailloux, la plupart calcaires, il s’en trouvoit de
très durs, de petrofilex, par exemple, même de
. jade,

a
SS
aia

—s
iiad

#08 ILLUSTRATIONS OF THE

jade, qui étoient tranchées tout t aufi nettement
que les autres *,”’

185. This defcription is no doubt accurate,
though it involves in it fomething of theory, viz,
that the fra@ure was made by the weight of
the ftone. This may indeed be true ; the ope.
ration probably belongs altogether to the fur.
face, and is one with which the powers of the
mineral regions are not dire@tly concerned. The
phenomenon, however, appears to me, on every
fuppofition, very difficult to explain. In the fpe-
cimen which I brought from Oban, the fmalleft
pieces of ftone are cut in two, as well as the lar-
geft. The confolidation and hardnefs of the mafs
are very great, and the connection of the differ:
ent fragments fo perfed, that it is no wonder the
whole fhould break as one ftone. But fill, that
the fracture fhould be fo exactly in one plane,
and without any fhattering, is not a little enig-
matical ; if it is indeed a fracture, it muft be the
confequence of an immenfe impulfe, very fud-
denly communicated.

Note

* Voyages aux Alpes, tom. ili, § 1371.

— e SN

R DEAS

HUTTONIAN THEORY.

>

o9

Nore xi. § 43.
Elevation and inflexion of the ftrata.

186. The evidence of the different formation
of the primary and fecondary ftrata, and of the
changes which the former have undergone, is
beft feen at the points where thofe ftrata come
into contact with one another. Dr Hutton was

| not the firt who obferved thefe junctions,

though the firft who rightly interpreted the
appearances which they exhibit. He has men-
tioned obfervations of this fort by De Luc on
the confines of the Hartz ; by the author of the
Tableau de la Suiffe, at the pafs of Yetz; by
- Voight, in Thuringia; and Schreiber, at the
= mountain of Gardette *.

The leading facts to be remarked, are,

_ 1, The vertical or very upright polition of
= the primary. or lower ftrata.

1. The fuperftratification of the fecondary,
in a pofition nearly horizontal, fo as to be at
_ tight angles to thofe on which they reft.
ui. The interpofition of a breccia between

mA 3 them ; or, as happens in many cafes, the tranfi-
| tion of the loweft of the fecondary beds into a

O breccia,

‘Steen cneeene:

* Theory of the Earth, vol. i, from p. 410, to 453-

gro ILLUSTRATIONS OF THE

breccia, containing fragments fometimes worn,
fometimes angular, of the primary rock.

This laft is a phenomenon extremely general,
and all our fubfequent information confirms Dr
Hutton’s anticipations concerning it. ‘ It wil}
be very remarkable,” he fays, “ if fimilar ap-
pearances, (fuch as thofe of the breccia defcri-

bed by Voight), are always found upon the junc-

tion of the Alpine with the level countries #,”
Sauffure, ina part of his work, not publithed when
Dr Hutton wrote this paflage, has attefted the ge.
nerality of the fact with refpe@ to the whole
Alps, from the Tyrol to the Mediterranean:
“ Un fait que Pon obferve fans aucune excep-
tion, ce font les amas de débris, fous la forme de
blocs, de breches, de poudingues, de grés, de
fable, ou amoncelés, et formant des montagnes,
ou des collines, difperfée fur le bord exterieur,
ou méme dans les plains qui bordent la chaine

des Alpes +.” |
This paflage is perfectly decifive as to the ge-
nerality of the fact, that the Alps, from the Ty-
rol to the Mediterranean, are bordered all round
by pudding-ftones or breccias. At the fame
time, it is neceflary to remark, that M. Sauffure,
by enumerating loofe blocks and fand, along with
pudding-ftones, breccias and grit, confounds to-
gether things which are extremely different, and
which

erage

* Theory of the Earth, vol. i. p. 448.
+ Voyages aux Alpes, tom. iv. § 2330.

= grounded the hypothefis of the double raifing
of

HUTTONIAN THEORY. 21%

which have had their origin at periods extremely
remote from one another. The confolidated
rocks of breccia, pudding-ftone and grit, though

they are indications of wafte, have received

their prefent charaCter at the bottom of the fea:
the loofe blocks of ftone, the fand and gravel, on
the other hand, are the effets of the wafte now
going forward on the furface of the land, and

‘are the materials out of which rocks of the three

kinds juft mentioned may hereafter be compofed.
If fo fkilfal a mineralogift as Sauffure is guilty
of fuch inaccuracy, it muft be afcribed to the

confufion neceflarily arifing from the fyftem

which he followed, and not to his own want of
difcrimination. 3

187. The fame phenomenon, of a breccia cir-
cumicribing the primary mountains, is met with
in Scotland ; and the Grampians, wherever they

Ü are bounded by fecondary ftrata, whether on

the fouth or north, afford examples of it. The
breccia generally confilts of the fragments of the
primary rock, moft commonly rounded, but
fometimes alfo angular, united by a cement of
fecondary formation, and the whole difpofed in
horizontal beds. It was on the conftancy of this
accompaniment of the primary ftrata, and on
the great quantity of highly polifhed gravel of-
ten included in thefe breccias, that Dr Hutton

up

212 ILLUSTRATIONS OF THE |

up and letting down of the. ancient flrata. See
§ 43. :

188. As the {pots where the primary and fe.
condary rocks may be feen in contact with one
another are of great importance in geology, and
prefent to the fenfes the moft ftriking monu-
ments of the high antiquity and great revolu-
tions of the globe, it may be ufeful to point out
{fuch of them as have been obferved in this ifland,
To thofe which Dr Hutton has defcribed, I have
a few more to add, the refult of fome geological
excurfions, which I made in company with the
Right Honourable Lord Wess Seymour, to
whofe affiftance I have been much indebted i in
the profecution of thefe inquiries.

189. The moft fouthern junction which we
obferved is at ‘Torbay, where the ancient fchil-
tus which prevails along the coaft, from the
Land’s End to that point, receives a covering of
red horizontal ftandftone, the fame which com-
pofes the greater part of Devonfhire. The fpot
where the immediate contact is vifible, is on the
fhore, a little to the fouth of Paynton; and
one circumftance, which among many others
ferves to diftinguith the different formation of
the two kinds of rock, is, that the fchiftus, which
is elevated here at an angle of about 45°, is full
of quartz veins, which veins are entirely con-

fined

-HUTTONIAN THEORY. 213

fined to it, and do not, in as far as we could ob-
ferve, penetrate into the fandftone, in a fingle
inftance. It is probable, that on the north fhore
of the bay, the fame line of junétion is vifible:
we faw it at Babicomb Bay, fill more to the
northward.

190. From this place, the fecondary ftrata of
different kinds prevail without interruption,
along the coaft of the Britifh Channel, and of

_ the German Ocean, as far ‘as Berwick upon
' Tweed, and for fome miles beyond it. The

fea-coaft then interfects a primary ridge, the
Lammermuir Hills, which traverfes Scotland
from eaft to weit, uniting, near the centre of the
country, with the metalliferous range of Lead-
hills, and afterwards with the mountains of Gal-
loway. ‘The fe@ion which the fea-coaft makes
of the eaftern extremity of this ridge, is highly

inftructive, from the great difturbance of the
_ primary ftrata, and the variety of their inflex-

ions. The junction of thefe ftrata with the
fecondary, on the fouth fide, is near the little
fea-port of Eyemouth, but the immediate con-
tact is not vifible.

On the north fide of the ridge, the jun&tion is
at a point called the Siccar, not far from Dun-
glais, the feat of Sir James Hall, Baronet. By
being well laid open, and diffe@ed by the work-
ing of the fea, the rock here difplays the rela-
tion between the two orders of ftrata to great

| O 3 advantage.

214 ILLUSTRATIONS OF THE

advantage. Dr Hutton himfelf has deferibed
this junction; Zbeory of the Earth, vol. i,
P. 464.

19t. From the point juft mentioned, the fe-
condary ftrata continue as far as Stonehaven,
where the fouthern chain of the Grampian
mountains is interfected by the fea-coaft. Here
a great mafs of pudding-ftone appears to lie on
the primary ftrata, but their immediate conta@
has not been obferved.

192. Going along the coaft toward the north,

the next junctions which we faw were on the

fhore, one near Gardenfton, and another near
Cullen, in Banff-fhire. The latter is very di-
ftin&; it is about a mile to the weftward of the
rocks called The Three Kings, where a red fand-
ftone, the lower beds of which involve much
quartzy gravel, lies horizontally upon very re-
gular, upright, and highly indurated ftrata.
Some of thele ftrata are micaceous, and others
of the granulated quartz, mentioned in § 152.
193. This laft is, I believe, the moft northern
junction which has been obferved in our ifland.
‘The weitern coait furnifhes feveral more, which

however are not all vifible. The line of fepa-

ration, between the primary fchiftus of the
Grampians and the fanditone which covers it,
is interfected at its weftern extremity by the
Frith of Clyde, not far from Ardencaple in Dun-
bartonthire. The two kinds of ftone ean be

traced

1
[
d
|
4
i
;

HUTTONIAN THEORY. ois

hy traced within a few yards of each other, but
Mi not to the actual contact: the beds of fandftone
| neareft the fchiftus form as ufual a breccia, load-
My ed with fragments of the primary rock. The
it, fecondary rock, which begins here, continues
i for about fifty miles fouth, to Girvan in Ayr-
i) fhire, where the primary fchiftus again rifes up,
lt) but is not feen in contad with the fecondary.
on = It extends to the Mull of Galloway and the
| fhores of the Solway Frith.

wi The Hle of Arran, however, not far diftant

nth _ from this part of the coaft, contains a junction
rw at its northern extremity, where fecondary ftra-
yi ta of limeftone lie immediately on a primary

ff micaceous {chiftus. This is defcribed by Dr
_ Hutton, and was the firt phenomenon of the
kind which he had an opportunity of examin-
ing *. The jundion is vifible but at one fpot, and
is not feen fo diftin&ly as in fome of the inftances
| jut mentioned ; but the great quantity of pud-
, ding-ftone near it, renders it more interefting
"than it would be otherwife. As the greater
part of this little ifland is furrounded by fecon-
dary ftrata, other junctions might be expected
_ to be vifible.
= 194. On the coaft of England and Wales, from
the Solway Frith to the Land’s End, though there
are feveral alternations from fecondary to pri-
O4 mary

J * Theory of the Earth, vol, i, p. 429.

216 ILLUSTRATIONS OF THE

mary ftrata, I know not that any of them have

been obferved. At St Bride’s Bay, in Pem-

brokefhire, the primary and fecondary ftrata are’
feen very near their junction; but the precife

line I believe is not vifible. The coal-pits in

the fecondary ftrata, approach here within a few

hundred yards of the primary. The fecondary

itrata which commence at this place, occupy both

fides of the Briftol Channel, and meet the Cor-

nifh {chiftus, which extends acrofs the north of
Devonthire to the Quantock Hills, in a line that

may be looked for on the fea-coaft, fomewhere

between Watchett and Minehead.

195. Befides the fea-coaft, the beds of rivers
may be expected to afford information on this
fubje&t. To the inftances I have mentioned, I
have accordingly two others from the inland
country to be added. One of them is from the
river Jed, a little way above Jedburgh, where
the fecondary ftrata are feen lying horizontally
on the primary, a fection of both being made by
the bed of the river. The phenomena here are
very diftind, and ftrongly marked: Dr Hutton
has defcribed and reprefented them in a plate *.
He has mentioned another junction, not far from
this, which he faw in the Tiviot. Both thefe
belong to the fame primary ridge with the Siccar
Point.

196. I

* Theory of the Earth, vol.i, p. 430.3 alfo plate 3

HUTTONIAN THEORY. ary

196. I fhall mention only one other, which
was difcovered by Lord Webb Seymour and
myfelf, at the foot of the high mountain of

E Ingleborough, in Yorkfhire. As we went along

the Afkrig road from Ingleton, about a mile and
a half from the latter, an opening appeared in
the fide of the hill, on the right, about one hun-
dred yards from the road, formed by a ‘large

ftone, which lay horizontally, and was {upported

by two others, ftanding upright, On going up
to the fpot, we found it was the mouth of a
{mall cave, the ftone lying horizontally, being
part of a limeftone bed, and the two upright

ftones, vertical plates of a primary argillaceous
fchiftus. The limeftone bed, which formed the
| roof of the cave, was nearly horizontal, decli-

ning to the fouth-eaft ; the {chiftus nearly verti-
cal, ftretching from north-weft by weft, to fouth-

- eaft by eaft. The {chiftus, though clofe in con-

tact with the limeftone, feemed to contain no-
thing calcareous, and did not effervefce with
acids in the flighteft degree.

As this cave is at the foot of Ingleborough,
a cold wind, 24° below the temperature of the

; external air, which iffued from the mouth of it,
4 might very well be fuppofed to come from the

inmoft receffes of that mountain. Ingleborough,
Which confifts entirely of ftrata of limeftone and

{| 8stit, nearly horizontal, and alternating with one

another, rifes to the height of 1800 or 2000 feet
above

218 ILLUSTRATIONS OF THE

above the fpot where we now ftood. This, I be.

lieve, is the greateft thicknefs of fecondary ftrata

that has ever been obferved incumbent on the
primary, and it is therefore a geological faq
highly deferving of attention. The country all
round, toa very great extent, is compofed of

limeftone, with a few beds of grit interpofed,

and forming, befide Ingleborough, fome other
high mountains, fuch as Wharnfide and Penni-
gant, all refting, it is probable, on the fame
foundation,

At the fpot juft defcribed, no breccia appear-
ed to be interpofed between the primitive and
fecondary rock ; but we found a breccia at ano-
ther point of the fame junction, not far di-
fant. This was at a cafcade, in the river
Greata, called Thornton Force, about two miles —
and a half from the place juft mentioned, The
Greata here precipitates itfelf from a horizon-
tal rock of limeftone; and, after a fall of a-
bout eighteen or twenty feet, is received into
a bafon which it has worked out in the pri-
mary {chiftus. This {chiftus is in beds al-
moft perpendicular ; it exadly refembles that
which has juft been defcribed, and ftretches
nearly in the fame direCtion. On the fouth fide
of the river a breccia was feen, lying upon the
{chiftus, or rather, it might be faid, that the
loweft beds of limeftone contained in them ma-
ny rounded fragments of ftone, which, on com-

parifon,

E fi

a Se

HUTTONIAN THEORY. 219

parifon, refembled exactly the {chiftus under-
neath. The primary rock itfelf is here feven or
eight hundred feet above the level of the fea.

The fame {chiftus, fomewhat lower down the
valley, and nearer to Ingleton, appears in large
quantities, and is quarried for flate. Here, how-
ever, the immediate junction of the limeftone
and ichiftus does not appear. ,

I have dwelt longer on the defcription of thefe
appearances than on any others of the fame kind,
becaufe, from the great mafs of fecondary ftrata
which here covers the primary, the circumftan-
ces are fuch as we cannot expect to fee very
often exemplified. ©

197. The Lakes of Cumberland are muchvifited
by travellers; and it may be worth remarking,
on that account, that, as the fite of thefe lakes
is a patch of primary country, bounded on all
fides by fecondary, fo, in the rivers that run
from the lakes, fuch jun@ions as we are now
treating of may be expected to be found. Un-
der Dun-Mallet, on the fide toward Ulles Wa-
ter, we obferved a breccia, which was in horizon-
tal layers, and feemed to lie on the primary
ichiftus, fo that the whole hill is perhaps a piece
of more indurated breccia, or fecondary rock,
which has refifted the wearing and wafhing
down of the rivers better than the reft.

198. After afcertaining the fact of the diftur-
bance of the ftrata, and their removal from their
original

220 ILLUSTRATIONS OF THE

original pofition, it is of confequence to inquire
into the direGtion of the force by which thefe
changes have been produced. Now, if the dj.
fturbed or elevated ftrata, were every where in
planes, without bending or finuofity, it might
perhaps be hard to determine, whether that
force had acted in the dire&ion of gravity,
or in the oppofite. Either fuppofition would
account for the appearances ; and, as gravity is
a known force, providing we can find fome
place fit to receive the matter impelled down-
ward by it, its action would furnith the mot
probable folution of the difficulty.

It is on this principle that the Neptunian fyf-
tem proceeds, imagining, that certain great ca-
verns or vacuities having been opened in the in-
terior of the globe, a great part of the waters
which formerly covered its furface, retired into
them, and much of the folid rock alfo funk down
at the fame time. In this way, one extremity
of a ftratum has been elevated, while the other
has been depreffed, and a certain inclination to
the horizon has been given to the whole of it.
Thus one caufe ferves two purpofes; the va-
cuities in the interior of the earth account, both
for the depreflion of the fea, and the elevation
of the land; and the Neptunifts, if the pheno-
mena were all fuch as have been now ftated,
might boaft of a felicity of explanation, not very

nfual in their fyftem. 7
3 But

T
-N

HUTTONIAN THEORY. 22I

s But this appearance of fuccels vanifhes, when
% f the elevation and difturbance of the trata are
at more minutely examined, and are found to in-
a clude waving and inflexion, in a great variety

W of forms. It then becomes evident, that the
il beds of rock, at the time when they were di-
My = fturbed from their horizontal pofition, had
Ni’ not, their prefent hardnefs and rigidity, but
vy were, in a certain degree at leaft, foft and flexi-
iw ble. Without thefe qualities, they could not
i have received, as they have often done, the
wl curvature of a circle, not many feet, nay, not
| many inches, in diameter ; nor could they have
a) been bent into fuperficies, with their curvature
ti} in oppofite directions, fo that the fame furface is
wi in one part convex, and in another concave, on
i) the fame fide, with a line of contrary flexure in-
jmt terpofed. Thefe are appearances, not reconci-
jn) lable with the mere falling in, and breaking
ji down of indurated rocks. _

ii 199. The inflexions and wavings that we are
wt = here fpeaking of, though not peculiar to the
fi Primary ftrata, are found moft frequently among
4 them, and are perfeétly familiar to every one
| who has travelled among mountains with any
‘view to the ftudy of geology. The following
are a few inftances of this phenomena, out of a

f great number which might be produced.
Sauffure,

222 ILLUSTRATIONS OF THE

Sauffure, in defcribing the rout from Geneyg
to Chamouny, mentions many remarkable jn.
{tances of the bending of the ftrata, and parti-
cularly where the {mall ftream of Nant d’Ay.
penaz forms a cafcade, by falling over the face
of a perpendicular limeftone rock. The ftrata
of this rock are bent into circular arches, ex-
tremely regular, and with their concavity turned
to the left. What deferves particularly to be
remarked, is, that a mountain behind the caf.
cade has its ftrata bent in a direction oppofite to
the former, or with their concavity to the right,
There is no doubt that the ftrata of both rocks
are the fame, fo that a vertical feCtion of them
would give a curve, in the figure of an S*,
Thefe circumftances are mentioned by Sauflure,
and from them we may infer this other proper-
ty of thefe ftrata, that their fection by a hori-
zontal plane, muft exhibit a fyftem of ftraight
lines, probably all parallel to one another.

The fame mineralogift defcribes the calcareous

ftrata which compofe the mountain Axenberg, on -

the fide of the Lake of Lucerne, as having from
top to bottom of the mountain the form of the
letter S comprefled (écra/ce), with their curva-
ture in fome places very great. Thefe inflex-

ions

* Voyages aux Alpes, vol. i. § 472.; alfo, Theoty
of the Earth, vol. ii. p. 30.

HUTTONIAN THEORY. 223

ions are repeated feveral times, and often in con-
trary directions ; the layers are fometimes bro-
ken, where their curvature is greateft *.

On the fide of the fame lake, is another in-
- ftance of bent ftrata, in a mountain, of which
the beds are horizontal in the lower part, but
are bent at one end upwards, in the form of the
letter C. The horizontal part is of great extent,
and the rock is alfo calcareous ie

The Montagne de la Tuile, near Montmelian,
receives its name from the beds of rock being
incurvated in form of a tyle f. Among fecon-
dary mountains, the fame kind of phenomena are
obferved, though lefs frequently, and with lefs
variety of inflexion. The chain of Jura is fe-
condary, and the beds which compofe it are of
limeftone, or of grit: they are bent in fuch a
manner, that in a tranf{verfe fection of the moun-
tain, each layer would have the figure of a pa-
Tabola §.

200. The Pyrenees furnifh abundance of phe-
nomena of the fame kind, as we learn from the
Efai fur la Mineralogie des Pyrénées. The
i calcareous

* Voyages aux Alpes, tom. iv. § 1935.
+ Ibid. $ 1937-

f Ibid, vol. iii. § 1182, and plate i,

§ Ibid, tom. 1. § 334.

224 ILLUSTRATIONS OF THE

calcareous {trata of the valley of Afpe, repre. |

fented plate v. of that work, deferve particu.
larly to be remarked.

201. Our own ifland abounds with examples -

of the bending and inflexion of the ftrata, efpe.
cially the primary, and many of them very much
refembling thofe in the Alpes and Pyrenees,
On the top of the mountain of Ben-Lawers, in
Perthfhire, there isla rock, the face of which
exhibits a fection of a great number of thin
equidiftant layers, bent backwards and fòr-
wards, like thofe defcribed by Sauffure; and
this unequivocal proof of the rock having

once exifted in the ftate of a flexible and

tenacious pafte, is rendered more ftriking, by
the great elevation of the fpot, and the rug-
gednefs and induration, both of the ftone it-
felf, and of every thing that furrounds it. Ma-
ny other mountains in this trac confift of a
{chiftus, which is talcofe rather than mica-
ceous, and fubjeét, in a remarkable degree, to
the fort of finuofity and inflexion here treated
of,

The appearances of the primary ftrata on the
coaft of Berwickfhire, have been already men-
tioned, as affording much valuable infiruction
in geology. They alfo exemplify the waving
and inflexion of the ftrata ona large {cale, and
with great variety. A fection of fome of them

ee is

it

ee alias

HOTTONIAN THEORY. 225

js given by Dr Hutton, in his Theory of the

Earth, vol. i., from a drawing made by Sir James |

Hall. The nature of the curve fuperficies into
which the ichiftus is bent, is the better under-
ftood from this, that, befides tran{verfe fe@ions
from north to fouth, the deep indentures which
the fea has made, and the projeGing points of
rock, exhibit many longitudinal feétions, in a
direction from eaft to weit.

202. The dock-yards at Plymouth are in fe-
veral places cut out of a folid rock of primary
{chiftus, fingularly incurvated. The inflexions
are feen there to great advantage, being exhibi-
ted in three fections, at right angles to one ano-
ther, tranfverfe, longitudinal and horizontal.

203. From thefe inftances, to which it were
eafy to add many more, two conclufions may
be drawn. The firt of thefe is very obvious,
viz. that the ftrata muft have been pliant and
foft when they acquired their prefent form.
The bending of an indurated bed of ftone into
an arch of great curvaturéyand without fracture,
as in the preceding examples, is a phyfical im-

= pollibility. Sauffure has indeed obferved a frac-

ture to accompany the bending, in one or two
cafes; but it is an uncommon phenomenon,
and, where it happens, muft no doubt be under-

~ flood to indicate an imperfe@ flexibility. Now,

if it be granted that the firata were at any time
foft

226 ILLUSTRATIONS OF THE

foft and flexible, fince their complete formation, |
it will be found impoffible to deny their having
been foftened by the application of heat. -

204. ‘Phe fecond conclufion, alluded to above,
refults from a property, which belongs very ge-
nerally, if not univerfally, to the inflexions of
the ftrata. This confifts in their curvature
being fimple, or in one dimenfion only, likea _
cylindric fuperficies, not double, or in two di-
menfions, like the fuperficies of a {phere or
{pheroid. This may be otherwife expreffed,
by faying, that the fections of the bent ftrata,
by a horizontal plane, are ftraight lines, pa- :
rallel to one another. On this account, every
fuch ftratum feems as if it were bent over an
axis, and the axes of all thefe different bendings,
for a great extent of country, are nearly paral-
lel. :
The truth of this is evident, where the ftrata
are feen both tranfverfely and longitudinally.
It holds remarkably of the primary fchiftus on
the coaft of Berwickfhire; where the beds of
rock, if cut tranfverfely, by a vertical plane,
exhibit the figures of very complicated curves,
with various maxima and minima, and points of
contrary flexure; but, if they are cut by a ho-
rizontal plane, the fection will produce nothing
but ftraight lines, nearly parallel.

205. The

=

=e

HUTTONIAN THEORY. 229

205. The conftancy of the direGtion of the
primary ftrata, when eftimated by their inter-
fection with the horizontal plane, is often very
remarkable. Their clevation and flexure are
fubject to great and fudden changes, fo as to
pafs not only from greater to lefs, but from one
fide to the oppofite, within a {mall diftance ;
but the horizontal line in which they /retch,
ufually preferves the fame bearing to a great
extent. The general direction of the primary
ftrata, in the fouth part of Scotland, is from
E. N. E. to W. S. W.; and the fame is nearly
true of thofe which compofe the ridge of the
Grampians on the north, and the hills of Cum-
berland and Weftmoreland toward the fouth,
though between the fchiftus of thefe three tracts,

theré is no communication at the furface, each

being entirely feparated from the one next it,
by the interpofition of fecondary ftrata. I have
already mentioned the obfervations of Lord
Webb Seymour and myfelf, at the foot of Ingle-
borough ; and it appears from them, that the
vertical fchiftus on which that mountain refts,
though it fill preferves an eaftern and weftern
dire@tion, varies feveral points from that of the
More northern ftrata. ‘The ftrata of Wales re-
turn more to the firft-mentioned direction, and
thofe of Devonthire and Cornwall agree with it
very nearly. In all this, it will be eafily con-

P 2 ceived,

228 ILLUSTRATIONS OF THE

ceived, that I do not mean to fpeak with abfo-
ute precifion, or to deny the exiftence of great
local irregularities. The refult given is only a
kind of average, deduced from obfervations
hardly fufceptible of great exactnefs, and not
yet fufficiently multiplied to give to the con-
clufion all the accuracy it may attain.

206. This tendency of the primary ftratato °
take a uniform dire&tion, has alfo been obferved
in other countries. Sauffure remarked in the
Alps, that the beds of fchiftus are generally pa-
rallel to the chains of mountains compofed of
them *; and this remark is probably applica-
ble to all mountains confifting of primary ftrata.
The general direction, therefore, of the {chiftus
of the Alps, muft be confined between W. 10° S.
and W. 40° S. In the Pyrenees, the direction
of the ftrata is about W. N. W +. If Sanflure’s.
rule may be depended on, the {chiftus of the
Altaic, and moft of the other great chains in
the old continent, are in directions that run con-
fiderably to the fouth of weft. The Ourals,
and perhaps fome other of the northern chains,
are however entirely different- In the Ourals,

|

as we learn not only from the general direction of
the chain, but from a feCtion of it in the roth vo-
lume

* Voyages aux Alpes, tom. i. § 577°

+ Efai fur le Mineralogie des Pyrenées.

HUTTONIAN THEORY. 229

lume of the Nova Ata of Peterfburgh, (tab. 12.),
the direCtion of the ftrata is nearly from N. to S:
This laft is probably the direction in the great
chains of South America; fo that the uniformity
of direction in the primary ftrata, which fome
mineralogifts would extend to thofe of the whole
earth, is certainly imaginary, though there can
be no doubt that it extends over "a large por-
tions of the earth’s furface ¥.

207. The

* It is perhaps unneceflary to obferve, that the two
propofitions, that the interfedctions of the ftrata with the
horizon are parallel lines; and that they are lines which
preferve the fame bearing with refpeé to the points of
the compafs; are nearly the fame thing for tra@ts of
thoderate exterit, but for large portions of the earth’s
furface are extremely different. If, for inftance, the
belt of primary vertical {chiltus, which traverfes the
fouth of Scotland, were to be produced eaftward in thé
fame plane, from its northern extremity, where its di-
tection is E.N. E. and its latitude 559.54’, it would
cut the meridian always lefs obliquely as it advanced,
till, having increafed its longitude about 260.28’, it
would be at right angles to the meridian, and its direc-
tion of confequence due eat and weft. This would
happen in the parallel of 589.51’, (on the fhore of the
Gulf of Finland, near Revel), the ftrata being now ex-
tended about 880 G. miles from the Siccar Point. Con-
verfely, vertical ftrata, having the fame bearing with

Je refpe&

230 ILLUSTRATIONS OF THE

207. The tendency of the primary ftrata to
remain {traight in the horizontal direGtion, and
to be bent in the vertical, is a phenomenon
which points very directly to the caufes from
whence it has arifen. A furface of fimple cur-
vature, or a furface ftraight in one diredtion, is

what

wefpect to. the meridian, may be im planes very much.
inclined to.one another. A ftratum which bears eaft

and weft in Cornwall, and one that does the fame at the

eaft end of the Altaic chain, will be in planes, which, if

produced, would cut one another at right angles. All
this is fufficiently plain from the doétrine of the fphere,,
and is mentioned here, merely as a caution to prevent
too hafty conclufions from being drawn:from any corre-
fpondence of bearing among the ftrata of remote coun-
tries.

For the fake of thofe who would. deduce the medium
bearing of any body of ftrata from a number of obfer-

vations, it may be proper to take notice, that the true

average is not to be found by fimply taking an arith.
metical mean among all the obfervations. A more ex-
act way is to work by the traverfe table, as in keep-
ing a fhip’s reckoning, (fuppofing the diftance run to be

always unity), and to compute from the obferved bearings’
the amount of all the fouthing or northing, and alfo of all.
the eafting or wefting. The fum of all he latter, di-
vided by the fum of all the former, is the tangent of
the angle which the general dire¢tion of the ftrata makes:

with the. meridian.

HUTTONIAN THEORY. 232

uy what the application of forces to different points
| ofa plane, which is flexible, though with a cer-
U | tain degree of rigidity, will naturally produce.
by The fuppofition, therefore, that thele ftrata were
wl once flat and horizontal, and were impelled up-
Mi ward from that fituation before they had be-
My come rigid or hard, will explain their having
>| the kind of curvature which removes them as
my little as poffible from their original condition.

as But no other hypothefis affords any reafon why

ty they fhould have that curvature more than any
hi | other. From the falling in of roofs of caverns, :
A ] we mightexpec fracture and diflocation, without
ne any order or regularity ; but certainly no bend-
om ing or finuofity, nor any fymmetrical arrange-
om ment. If, as fome mineralogilts allege, the curva- _
| ture, as well as inclination of the ftrata, arofe from
fim! the irregularities of the bottom on which they
nt were depofited, why is the former in one dimen-
tt fion only, and why is it not in every direction,

itl like that of hills and valleys, or the actual furface
i of the earth? Or, laftly, if the whole ftrudure

@ of the primitive mountains is an effed of cryftal-
oF lization, and if thefe mountains are now fuch as
i they have ever been from the time of their con-
i _ folidation, whence is it, that, in their bendings
_ the law juft mentioned is fo conftantly obfer- `

ved? Indeed, the idea of afcribing the inflex-
ions of the ftrata to cryftallization, though fug-
gefted

432 ILLUSTRATIONS OF THE

gefted by Sauffure *, and fince become a favonrs
ite fyftem with feveral mineralogifts, appears to
me in the higheft degree unfatisfaGtory and il-
lufive. The purpofe for which cryftallization
is here introduced, is not to give a fpecific
figure to a particular fubftance, but to arrange
the fubftances which it has formed and figu-
red, according to certain rules; a work which
we know not how it is to perform, and in
which we have no experience of its power,
Accordingly, this principle does not account,
in any way whatever, for the circumftances
which attend the inflexion of the ftrata, for
the fimple curvature which they affect, nor for
that parallelifm of their layers, which, in all
their bendings, is fo accurately preferved. It
does, indeed, fo little ferve to explain thefe
facts, that, were the appearances completely
reverfed ; did the ftrata afflume the moft com-
plex, inftead of the moft fimple curvature;
inftead of equidiftant, were they converging,
or alternately receding and approaching to one
another; the theory of cryftallization might
be equally applied to them. The ftate of the
phenomena is a matter of perfect indifference
to fuch a theory as this: all things are explain-
ed by it with the fame facility ; the ftraight and

; the

% Voyages aux Alpes, tom. 1, § 475.

HUTTONIAN THEORY. 233

> the crooked, the {quare and the round, the move-
IE able and the immoveable. Is it not evident
ti = that fuch an explanation is a mere word; or, if
ay) any thing more than a word, an expreffion of
tt | our ignorance, fo awkward and indirect, as to
ly) deprive us of whatever credit might have been
by gained by a plain and candid avowal of it ?
hig It fhould never be forgotten, that a theory
di = Which accounts for any thing, and a theory which
Mi accounts for nothing, tand precifely on the fame

Wf footing, and ought to be banifhed from all parts
mt of philofophy, as they have been from thofe
tt} fciences which are juftly honoured with the name
tii} ofaccurate. The animated orbs of Ariftotle, and
nil the vortices of Des Cartes, have long ceafed to be
jl) mentioned in phyfical aftronomy ; the firft, be-.
hel | caufe they accounted for every thing alike ; the

tj fecond, becaufe, when they accounted for one
t thing, they never could be made to account for
ma another. Both theories, therefore, have very
ih properly been rejected; and, when geology
ot fhall undergo a fimilar purification, the princi-
if ple we have been contfidering will not be the
b only facrifice required of the Neptunian fyftem.
P| 208. An appearance obferved in fome kinds
ih of primary {chiftus, which clearly indicates their
i | depofition by water, and in planes very different
i E from thofe in which we now fee them, though

it might have been introduced before, is alfo
much

234 ILLUSTRATIONS OF THE

much conneéted with the prefent argument,
This appearance confifts of {mall wavings or un.
dulz on the furface of the plates of {chiftus,
precifely fimilar to thofe marks which are left
by the fea on a gently inclining beach of fand,
at the ebbing of the tide. All the fpecies of
{chiftus do not feem to afford inftances of thefe
wavings. The rocks which do fo, are, I think,
chiefly of the argillaceous kind, but often highly
indurated; fo that the lamine containing the
firini are not to be torn afunder but with
great difficulty. Inftances of it abound in the
{chiftus of Berwickfhire, and are alfo not unfre-
quent in that of Galloway. All muf agree
about the agent which produced thefe marks ;
it could be no other than the fea; but it mutt
have been the fea acting on loofe, fmall and
round particles, lying on a furface which was
nearly horizontal.

209. Dr Hutton’s theory is no where ftronger,
than in what relates to the elevation and inflex-
ion of the ftrata ; points in which all others are
fo egregioufly defeQive. The phenomena to be
connected are here extremely various, and even
in appearance contradictory : the horizontality
of one part of the ftrata; the inclined or verti-
cal pofition of another; the perfect planes in
which one fet are extended; the breaking and

diflocation

HUTTONIAN THEORY. 235

in| diflocation found in a fecond ; the inflexion and
ty finuofity of a third ; and almoft every where the
“ wtmoft rigidity and induration, combined with
appearances of the greateft foftnefs and flexibi-
lity; the prefervation of a parallelifm of fu-
perficies in the midft of fo much irregularity,
and the affumption of a determinate fpecies of
curvature, under circumflances the moft diflimi-
lar ; all thefe appearances were to be connected
~ with one another, and with the confolidation of

the ftrata, and this is done by the twofold hypo-
thefis, of aqueous depofition, and the aion of fub-
terraneous heat. When thefe circum{tances are
fairly confidered, and when the fhifts which other
fyftems are put to on this occafion are remem-
bered, I think it will be granted, that few
attempts at generalization have been more fuc-
_eefsful, than that which is here made by the
_ Huttonian Theory.

210. To the fa@ of the elevation of the ftra-
ta, the ftudy of geology is much indebted. The
ftratified form of a. great proportion of the
earth’s furface, gives to minerals that organiza-
tion and regularity, which makes their difpofi-
tion an object of fcience, and their inclined po-
fition ferves to bring that organization into view,
from far greater depths than we can ever reach
by artificial excavations. If, for inftance, the ter-

mination of frata, that make with the horizon
an

236 ILLUSTRATIONS OF THE

an angle of. 30°, lying one over another, is feex
for a horizontal diftance of two miles ; then it
is certain, that if thefe ftrata have that extent
under ground, which may be reafonably fup:
poled, the thicknefs of the whole mafs, mea.
fured by a line perpendicular to its {tratifica.
tion, is half the horizontal diftance, or amounts
to one mile. It would alfo require a pit to be
funk from the uppermoft of thefe ftrata, to the
depth of (2 miles x tan 30°, =) 6093 feet, be.
fore it could interfe@ the undermoft; and
therefore, if we fuppofe the fame ftratum to pre-
ferve the fame character for the extent of fome
miles, we obtain the fame information from in-
{pecting the edge-feams, and fee in reality as
far into the bowels of the earth, as if we had
funk a perpendicular fhaft to the depth of 6000
feet. =

In general, the length of the horizontal line
drawn acrofs the ftrata, from the loweft in po- -

fition to the higheft,, multiplied into the fine of
the inclination of the ftrata to the horizon, gives
the thicknefs of the whole, meafured perpendi-
cularly to the plane of the ftratification: and
the fame horizontal diftance, multiplied into the
tangent of the inclination, gives the actual depth
at which the loweft ftratum would meet a per-
pendicularto the horizon, drawn from the high-

eft extremity of the upper ftratum.
In

ee nes ee

HUTTONIAN THEORY. 237

In many cafes, the extent of ftratified mate-
rials admitting of fuch an examination as this,
js much greater than has now been fuppofed.
M. Pallas defcribes a range of hills on the
fouth-eaft fide of the peninfula of the Tauride,
which is cut down perpendicularly toward the
fea, and offers a complete fection of the parallel
beds of a primary, or, as he calls it, an ancient
limeftone, inclined at an angle of 45° to the hori-
zon ; and this fection continues for the length of
130 verfis, or about 86 Englifh miles. The
beds are fo regular, that M. Pallas compares
/ them to the leaves of a book*. The height of
thefe hills does not exceed 1200 feet, but the
real height of the uppermoft ftratum above the
undermoft, is 86x \/; = 86 x $ = 61 miles
nearly.

4 If therefore we conceive that there is no fhift
Ji in all this great fyftem of ftrata, we in reality
ind are enabled, by means of it, to fee no lefs than
igi 61 miles into the interior of the earth, nearly
_ a65th part of the radius of the globe. It is

# true, that we can hardly fuppofe fo great a body
gf ftrata to have been raifed without fhifting,
oe fo that we muft diminifh this depth confider-
A ably ; but were it reduced even to one-half, it
$ T Se
if

ji * See Nova Aĝa Acad. Petropol, tom, x. (1792,)

P: 257.

238 ILLUSTRATIONS OF THE

will appear, that men fee much farther into the
interior of the globe than they are aware of,
and that geologifts are reproached without reafon
for forming theories of the earth, when all that
they can do is but to make a few feratches on
its furface. Art indeed can do little more; but
nature {upplies the deficiency, and makes difco.
veries to the attentive obferver, on the fame
great fcale with her other operations.

The fimpleft account that can be given of the

vaft body of parallel and highly inclined ftrata

juft mentioned, is, that it confifts of the ends of
horizontal ftrata,.or of ftrata not greatly inclined,
that have been forced up when they were all
foft and flexible. This is a much more con-
ceivable fuppofition than Pallas’s, viz. that the
greater part of this mafs has funk down into
fome vaft cavern in the interior of the earth.

Nore

HUTTONIAN THEORY. 239

N ,

tj Nore XII. § 53.

li

l : Metallic Veins.

hs 21r. The large fpecimens of native iron found

iy ‘jn Siberia and Peru, mentioned above, § 51r.,
ty are among the moft curious facts in the natural
hiftory of metals. It has been doubted, how-
ft ever, by fome, whether they really belong to
it, natural hiftory, or are not rather to be account-
ii ed artificial produ&ions. If they had been
im’ found in the heart of rocks, or in the midft of
ti metallic veins, no doubt of this fort could pofi-
(m bly have been entertained; but, as they he
tty quite on the furface, in the middle of flat coun-
it) tries, and at a diftance from any known vein of
, metal, the conjecture that they may be artificial,
| and the remains of the iron founderies of an-
| cient and unknown nations, is at firft fight not
| entirely deftitute of probability. This proba-
ith bility, however, will appear to be the lefs, the
| More carefully the fpecimens are examined,
| The metal is too perfe@t, and the mafies too
| large, to have been melted in the furnaces, or to
have been tranfported by the machinery, of a
rude people. The fpecimen in South Amefica
Weighs 300 quintals, or about 15 tons, and is

foft

240 ILLUSTRATIONS OF THE

foft and malleable *. The Siberian {pecimen,
defcribed by Pallas, is alfo very large; it is toft
and malleable, and full of round cavities, con-
taining a fubftance, which, on examination, has
been found to be chryfolite +. Now, it is cer.
tainly quite impoffible, that, in an artificial fu-
fion, fo much chryfolite could have come by
any means to be involved in the iron ; but, if
the fufion was natural, and happened ina mi-
neral vein, the iron and the chryfolite were both
in their native place, and their mecting toge-
ther has nothing in it that is inexplicable.

212. Some circumftances in the. defcription
of the fpecimen in South America, fuch as the
impreflions of the feet of men and of birds on
its furface, are not to be accounted for on any
hypothefis, and certainly require more care-
ful inveftigation. It is faid, that this iron is
very little fubje& to ruft, and the analyfis of a
piece of it by Prousr makes it probable, that
it owes this quality to its union with nickel f.
It appears, alfo, that the country of Chaco,
where this fpecimen was found, affords many
others of the fame kind, one of which is men-
tioned in the defcription above referred to. That

country

* Phil. Tranf. 1788. p. 37. alfo p. 183, &e.
+ Kirwan’s Mineralogy, vol.ii. art. Native Iron.

+ Annales de Chimie, tom. xxxv. Mefiidor, p. 47e

HUTTONIAN THEORY. 241

country lies on the eaf fide of the Plata, and is
afplain, extremely level, and of vaft extent;
without any appearance of mineral veins; but
fuch veins may neverthelefs exit undilcovered,
in a tract fubje@ to periodical inundations, and
where the native rock is covered with alluvial
earth and gravel to a great depth. The veins may
be wafhed away, and the more durable fubftan-
ces, fuch as thofe pieces of native iron, may be
left behind; and, though they muft be of a for-
mation extremely ancient, according to this hy-

JE pothefis, they may not have been very long on

the furface.

213. Specimens of native iron have been
found, lefs remarkable than the preceding for
their fize, but in circumftances that excluded

all idea of artificial fufion. Of this fort was

Marcraar’s {pecimen of native iron, the firt of
the kind that was known; it confifted of {mall
bits of foft and malleable iron, found in the
heart of a brown iron-ftone*. This makes it
certain, that native iron is a natural production,
and the mere circumftance of great magnitude,
in the {pecimens ‘before mentioned, does not en-
title us to doubt of their having that fame ori-
gin, It is a circumftance, befides, not in the

dleat material to this argument; the finalleft

J- piece

* Kirwan’s Mineralogy, vol, ii. p. 156.

242 ILLUSTRATIONS OF THE

piece of native iron being as much a proof of
fufion as the greateft; and the fpecimen of
Margraaf being juft as conclufive in favour of
the Huttonian Theory, as thofe of Pallas or De
Celis, fuppofing their reality as mineral produc-
tions to be completely eftablifhed. A metal
malleable and duétile, in ever fo fmall a quan-
tity, cannot be the refult of precipitation from
a menftruum, without a very particular combi-
nation of circumftances. Such a metal, on the
other hand, can be readily produced by igneous
fufion ; fo that here the negative and affirmative
parts of the inductive argument may both be
regarded as complete.

214. Mr Kirwan, in order to account for the
magnitude of the two large {fpecimens mentioned
above, fuppofes, that {mall pieces of native iron
(about the formation of which he appears to
have no difficulty), have been originally agglu-
tinated by petroleum, and left bare, when the
furrounding ftony or earthy maffes either wi-
thered or were walhed off *. This is no doubt
the mof fingular of all the opinions which have
been advanced on the fubje@ ; and, as it bor-
rows nothing from analogy, it admits of no
proof, and requires no refutation. None buta

chemift of eminence could have ventured with

impunity

ete

* Geol. Effays, p. 405,

eer

HUTTONIAN THEORY. 243

impunity on an affertion fo inconfiftent with all
the phenomena and principles of his {cience.
215. Aremark of the fame author, on the
fubject of the native gold found in the county
of Wicklow in Ireland, is entitled to more atten-
tion. “ That thefe lumps of native gold,” he
fays, “ were never in fufion, is evident from
their low fpecific gravity, and the grains of fand —
found in the midft of them. I found the {pe-
cific gravity of a lump of the fize of a nutmeg

| tobe only 12800, whereas, after fufion, it be-
E came 18700 *.”’

This argument is plaufible; but, I think,
neverthelefs inconclufive. The fand found in
the gold, accounts, at leaft in part, for its

lightnefs. It is only by repeated fufions that

any of the metals is brought to its utmoft pu-

rity and higheft fpecific gravity; and on no

fuppofition can the melting of gold in the
mineral regions, be very likely to feparate it. |

I from heterogeneous fubftances. That quartzy

fand fhould be found in it, after fuch a procefs, is

_ haturally to be expected. The impreflions which |
| the quartz cryftals have left on the Wicklow

gold, would be received as a full proof of the
fufion of that metal, if geologifts always regu-
Q2 lated

* Geol. Effays, p. 402.

244 ILLUSTRATIONS OF THE

lated their theories by the principles which de-
termine the belief of ordinary men.

216. Don Rubin de Celis, in the paper re-
ferred to above, mentions fome mafies of filver
found at Quantajaia, and alfo fome duft of pla-
tina, in terms that excite a ftrong defire to have
more information concerning them. They are
confidered by him as effects of volcanic fire; fo
we may conclude, that they contain evident
marks of fufion, and would in this fyftem be
aferibed to that heat, from which volcanic fire
is but a partial and accidental derivation. —

217. The ftate alfo in which gold and filver
are often found pervading mafles of quartz, and
fhooting acrofs them in every direction, furnithes
a firong argument for the igneous origin, both
of the metal and the ftone. From fach fpeci-
mens, it is evident, that the quartz and the me-

te, at the fame time; and it is hardly lefs
clear, that this fluidity did not proceed from fo-
lution in any menftruum: For the menftruun,
whether water or the chaotic fluid, to enable it
to diffolve the quartz, muft have had an alka-
line impregnation; and, to enable it to diffolve
the metal, it muft have had, at the fame time,
an acid impregnation. But thefe two oppofite
qualities could not refide in the fame fubjeđ;
the acid and alkali would unite together, 5

i

HUTTONIAN THEORY. 245

if equally powerful, form a neutral falt, (like
fea-falt), incapable of acting either on the me-
tallic or the filiceous body. If the acid was
moft powerful, the compound falt might act on
the metal, but not at all upon the quartz ; and if
the alkali was moft powerful, the compound
might a& on the quartz, but not at all on the
metal. In no cafe, therefore, could it a@& on
both at the fame time. Fire or heat, if fuffi-
ciently intenfe, is not fubjec to this difficulty,
as it could exercife its force with equal+¢effec&
on both bodies.

_ 218. The fimultaneous confolidation of the
_ quartz and the metal is indeed fo highly impro-
bable, that the Neptunifts rather fuppofe, that the
ramifications in fuch fpecimens as are here allu-
ded to, have been produced by the metal diifufing
itfelf through rifts already formed in the ftone *.
= But it may be anfwered, that between the chan-
` nels in which the metal pervades the quartz,
and the ordinary cracks or fiffures in ftones,
there is no refemblance whatever: That a fyf-
tem of hollow tubes, winding through a ftone,
~ {as the tubes in queftion, muft have been, ac-
cording to this hypothefis, before they were filled
by the metal), is itfelf far more inconceivable
_ than the thing which it is intended to explain ;

Q 3 | and

* Geol. Effays, p. gor.

246 ILLUSTRATIONS OF THE

and laftly, that if the ftone was perforated by
fuch tubes, it would ftill be infinite to one that
they did not all exaétly join, or inofculate With
one another.

219. The compenetration, as it may be call.
ed, of two heterogeneous fubftances, has here
furnifhed a proof of their having been melted
by fire. The inclufion of one heterogeneous
fubftance within another, as happens among the
{pars and drufens, found fo commonly in mine-
ral veins, often leads to a fimilar conclufion,
Thus, from a fpecimen of chalcedony, including
in it a piece of calcareous fpar, Dr Hutton has
derived a very ingenious and fatisfaétory proof,
that thefe two fubftances were perfe@ly foft at
the fame time, and mutually affeted each other
at the moment of their concretion *. i

Each of thefe fubftances has its peculiar form,
which, when left to itfelf, it naturally affumes ;
the fpar taking the form of rhombic crytftals,
and the chalcedony affe&ting a mammalated ftruc-
ture, or a fuperficies compofed of fpherical feg-
ments, contiguous to one another. Now, in the
fpecimen under confideration, the {par is inclu-
ded in the chalcedony, and the peculiar figure
of each is impreffed on the other; the angles and
planes of the fpar are indented into the chalce-

dony,

—

* Theory of the Earth, vol.i. p. 93.

HUTTONIAN THEORY. 247

dony, and the fpherical fegments of the chalce-
dony are imprinted on the planes of the fpar.
Thefe appearances are confiftent with no notion
of confolidation that does not involve in it the
fimultaneous concretion of the whole mafs; and
fuch concretion cannot arife from precipitation
from a folvent, but only from the congelation
of a melted body. This-argument, it muft be
remarked, is not grounded on a folitary {peci-
men, (though if it were it might fill be perfect-

ly conclufive), but on a phenomenon of which

there are innumerable inftances.

220. According to this theory, veins were
filled by the injection of fluid matter from be-
low; and this account of them, which agrees fo
well with the phenomena already defcribed, is
confirmed by this, that nothing of the fubftances
which fill the veins is to be found any where at
the furface. It is not with the veins as with
the ftrata, where, in the loofe fand on the fhore,
and in the fhells and corals accumulated at the
bottom of the fea, we perceive the fame mate-
tials of- which thefe ftrata are compofed. The
fame does not equally hold of metallic veins:
“ Look, fays Dr Hutton, into the fources of our
mineral treafures? Afk the miner from whence
has come the metal in his veins? Not from the
earth or air above, nor from the ftrata which
the vein traverfes: thefe do not contain an atom

Q4 of

248 ILLUSTRATIONS OF THE

of the minerals now confidered. There is but
one place from whence thefe minerals may have
come ; this is the bowels of the earth ; the place
of power and expanfion ; the place forti whence
has proceeded that intenfe heat, by which loofe
materials have been confolidated into rocks, as
well as that enormous force, by which the re-
gular ftrata have been broken and difplaced *,”

221. The above is a very juft and natural re-
fletion; but if, inftead of interrogating the
miner, we confult the Neptunift, we will receive
a very different reply. As this philofopher never
embarrafles himfelf about preferving a uniformity
in the courfe of nature, he will tell us, that though
it may be true, that neither the air, the upper part
of the earth’s furface, nor even the fea, contain at
prefent any thing like the materials of the veins,
yet the time was when thefe materials were all
mingled together in the chaotic maf, and con-
ftituted one vaft fluid, encompaffing the earth ;
from which fluid it was, that the minerals were
precipitated and depofited in the clefts and fif-
{ures of the ftrata.

222. It is alleged, in proof of this hypothefis,

that mineral veins are found to be lefs rich as.

they go farther down, whereas they ought to be
richer, if they were filled by the projection of
melted

—

a

* Theory ofthe Earth, vol.i. p. 130.

a ee ee ee

`
ee a

HUTTONIAN THEORY. 249

melted matter from below. But the fad, that

mines are lefs rich as they defcend farther,
though it may hold in fome inftances, is not ge-
neral, and may therefore be fuppofed to arife
from local caufes, fuch as are, in refpeé of us,
accidental, and beyond the limits to which our
theories can be expected to reach. Thus the
mines of Mexico and Peru are faid to be fub-
jet to the preceding rule; but in the mines
of Derbyfhire and Cornwall, the very contrary
is underftood to take place. Befides, what we

' are pleafed to call the riches of a mine, are
_ riches relatively to us, and relatively to a diftinc-

tion which nature does not recognife. The fpars
and veinitones which are thrown out in the rub-
bifh of our mines, may be as precious in the eyes
of nature, as conducive to the great objects of
her economy, and are certainly as chara¢teriftic
of mineral veins, as the ores of filver or gold, to

which we attach fo great a value. Unlefs the

former are in fmaller quantity, or lefs highly.
cryftallized at great than at fmall depths, which

_ Ibelieve is not alleged, no conclufion can be
_ drawn from fubftances, which occupy in gene-

ral but a {mall proportion of any vein, and, in
their diffemination through it, do not feem to

be always guided by the fame law.

223. Again, if the veins were filled by depo-
fition from above, we ought to difcover in them
. fee 3 fuch

250 ILLUSTRATIONS OF THE

fuch horizontal ftratification as is the effe@ of

depofition from water, and we ‘thould perceive

no marks of the materials having been introdu-

ced with violence into their place. The Neps |
tunifts cannot object to the trial of their theory

by thefe two fads.

As to the firft, it is acknowledged, that there
is a certain regular difpofition of the fubftances
in mineral veins, as ftated § 59, but it is one
which has hardly any thing in common with
the real phenomena of ftratification. It con-
fifts in the diftribution of the principal fubftan-
ces in coats parallel to the fides of the vein, each
fubftance forming a feparate coat. Ina vein,
for inftance, containing quartz, fluor, calcareous
{par, lead, &c. we might expe to find a lining
of quartz cryftals, applied immediately to the
walls of the mine, and following exadly the
irregularities of their furface; next, perhaps,
a coat of fluor, then of calcareous fpar, and laft of
Jead-ore in the centre of the vein, the fame or-
der being obferved on the oppofite fide. Thefe
fucceflive coats, it is material to remark, are not
in planes, but in uneven furfaces, of which the
inequalities are evidently determined by thole
of the walls, that is, of the rock which forms
the fides of the vein; neither are they horizon-
tal, but are parallel to the walls, whether thele
be perpendicular or inclined. Here, therefore,

. there

HUTTONIAN THEORY. ~ 254

there is no appearance of the action of that fta-
tical law which has directed the arrangement

of the other ftrata, and which tends to make the |

plane of every ftratum depofited by water per-
pendicular to the direction of gravity. The
coating of the veins has therefore been perform-
ed under the conduct of fome other power than
that which prefides over aqueous depofition.
If, as the Neptunifts maintain, the materials in
the veins were depofited by water, in the moft
perfect tranquillity, it is wonderful that we do

= not find thofe materials difpofed in horizontal
_ layers, acrofs the vein, inftead of being parallel

to its fides; and it feems very unaccountable,
that the common ftrata, depofited as we are told
while the water was in a ftate of great agita-
tion, have fo rigoroufly obeyed the laws of hy-
droftatics, (§ 38.), and acquired a parallelifm in
the planes of their ftratification, which ap-
proaches fo often to geometrical precifion ; while
the materials of the veins, in circumftances fo
much more favourable for doing the fame, have

_ done nearly the reverfe, and taken a pofition,
_ often at right angles to that which hydroftatical
= Principles require. This is a paradox which

the Neptunian fyftem has created, and which

__ therefore it is not very likely to refolve.

224. Mere words fhould have little power to
miflead, in a {cience which treats of fenfible ob-
jecis,

252 ILLUSTRATIONS OF THE

jects, fuch as are always eafily fubjeCted to the

examination of fight or of touch; yet there jg
fome appearance as if the Neptunifts were
mifled in this, and other inftances, by the
term firatification. Though an incruftation on
the perpendicular face of a rock has very little
affinity to a ftratum, fuch as we are accuftomed
to fee depofited by water, yet the fame name
being once impofed on both, mineralogifts have
proceeded to reafon concer ning them, as if they
were precifely the fame thing, and were both to
be afcribed to the fame caufe. Indeed, every
perpendicular or highly-inclined bed of ftone, is
inexplicable as an effect of aqueous depofition,
in a fyftem, unprovided, as the Neptunian is *,
with the means of raifing up fuch beds froma
horizontal into a vertical pofition. This obfer-
vation may alfo be extended to all cafes of

vertical ftratification. Water cannot direAly {

arrange its depofites in planes highly inclined,
and therefore I have often wondered to fee the
Neptunifts contending fo eagerly for the ftrati-
fication of certain rocks, fuch as granite, which,
being vertical, or highly inclined, was much
lefs friendly to their fyftem than the entire ab-
fence of all ftratification would have been. I
was difpofed to admire their candour, when the

2 ufe

a ol

* See preceding note.

— p

HUTTONIAN THEORY. 453

ufe which they made of the fact convinced me,
that I ought only to wonder at their inconfequen-
tial reafoning. The Huttonian Theory is, in-
deed, the only one which poffefles the means of
reconciling the elevation of the ftrata with their
horizontal depofition, and which is entitled to
confider ftratification, in whatever. plane it may
be, as originally the work of the ocean. The
geologifts who attach themfelves exclufively to
the action of water, will never be able to ex-
= tend the dominion of that element fo far as Dr
Hutton has done, by combining it with fire.
225. But, though the Neptunian fyftem were
provided with engines, powerful enough to raife
up ftrata from a level to a vertical plane, this
would avail nothing in the prefent inftance ;
fince, on no fuppofition, can the incruftations on
the perpendicular fides of a vein have ever been
horizontal. On no fuppofition, therefore, can
thefe incruftations be received as a proof of
aqueous depofition: it may indeed be certainly
inferred from them, that the matter which they
= confit of was fluid at the time of their forma-
tion; but the abfence of all appearance of a |
horizontal difpofition, in any part of the vein,
amounts nearly to a demonftration, that this
fluidity did not proceed from folution in a men-
ftruum. We muft therefore conceive the coats to
have been formed during the refrigeration of the
melted

454. ILLUSTRATIONS OF THE

melted matter inje@ed from the mineral regions

into the clefts and fiffures of the ftrata (} 59.)
226. Mineral veins, particularly at their jp.
terfeCtions with one another, contain abundant
marks of the moft violent and repeated diftur.
bance, ({ 56). Not to mention that they owe
their firt formation to the fra@ure and dif-
placing of rocks already confolidated, it ap-
pears, that they have originated at very differ-
ent periods, and that the birth of each has been
accompanied with convulfions, which fhook the
foundations of the earth. In Cornwall, for in-
ftance, the principal veins, and thofe which
they diftinguifh particularly by the name of
Lodes, have nearly the fame direGion with the
itrata or vertical {chiftus, extending from about
E. N. E. to W.S. W. Thefe, however, are of-
ten interfe&ted nearly at right angles by other
mineral veins, called Crofs Courfes, and this
hardly ever happens without the latter moving,
or, as it is called, heaving the former out of their
direGion. This plainly indicates, that the cro
courles are of later origin than the others, and
that their formation was accompanied with fuch
a force, as muft, in many inftances, have moved
the whole body of rock which conftitutes the
promontory of Cornwall, and probably much
more, for feveral yards, in a horizontal direc-
tion. Sometimes, alfo, both the longitudinal
and

Ne

HUTTONIAN THEORY. 453

and the crofs vein are forced out of their place

by a third. Thefe difturbances arife not only
from mineral veins, but from veins of porphyry
and granite, the production of which has been
attended with no lefs violence than of the
others.

227. What is here faid of Cornwall, is the
hiftory, in fome degree, of all mineral countries
whatever. The great horizontal tranflation
which has thus accompanied the formation of

4 veins; the movement impreffed on fuch vaft
d bodies of rock, and the frequent renewal of thefe
- immenfe convulfions ; are not to be explained by
the mild and daui dominion of the watery

element. They require the utmoft power that is

| known any where to exift, and were it not for the

admonitions of the volcano and the earthquake,

= we might doubt if even fubterraneous heat itfelf

poilefied an enegy adequate to thefe aftonith-

| ing effects.

228. From the heaving of one vein by ano-

ther, it is evident, that there was a force of pro-

trufion in the direction of one of them, that

adted at the time of its formation. This force
= cannot be accounted for on the fuppofition that
= veins were produced by the mere fhrinking of
the ftrata ; for the rocks could not, in that cafe,

have been rent afunder, and impelled forward at
the fame time. It appears mof likely, that fif-
fures

/

256 ILLUSTRATIONS OF THE

fures in the ftrata were made, at leaft in many
inflances, and the matter poured into them,
nearly at the fame time, both being effedts of
the fame caufe, the expanfive force of fubterra..
neous heat. .

229. It is remarked, at § 56., that the fhifting
of the ftrata is beft obferved where the veins
make a tran{verfe feCtion of beds of rock, con-
fiderably inclined to the horizon. It is alfo
true, that in fome cafes the near approach of —
the ftrata to the level, may make the fhifts pro. |
duced by the veins very eafy to be difcovered. —
Thus in Derbyfhire, where the mineral veins —
are in fecondary ftrata, nearly horizontal, there
is almoft no inftance in which the correfpond-
ing ftrata are not obferved to be on different le-
vels, on the oppofite fides of the fame vein.

230. The fad defcribed by De Luc, and re-
ferred to at § 55., may, for what we know of it,
admit of being explained in two ways. The
great wedge of rock which appears to be infu-
lated between two branches of the fame vem,
may either be a mafs that has been broken off,
and fuftained by the melted matter that flowed
all around it; or, it may be a mafs of rock con-
tained between two veins that are in reality
ditin, and of different formation. Whether
this laft fuppofition is the truth, would probably
be evident from a careful examination of both

parts

HUTTONIAN THEORY. 285

parts of the vein; as fome difference of charac-
ter cannot fail to be the confequence of differ-
ent formation. If no fuch difference is obfer-
= ved, the two branches muft be fuppofed to be-
_ long to the fame vein, and the only probable

explanation of the infulation of fo large a mafs

of rock will be by the firft-mentioned fuppofi- .

i | tion. This fact, therefore, notwithftanding the

q great attention M. De Luc has beftowed on it,
_ ftill requires further examination, before it can
- be decided whether it inclines to the Huttonian
; Theory, as on the firft fuppofition, or is, as on
the latter hypothefis, equally balanced between
it and the Wernerian. :
231. Whatever be the cafe with this fact, the
_ general one of pieces of rock being found infu-
i lated in veins, is certainly favourable to the no-
tion of an injeĝed and ponderous fiuid having
q originally fuftained them. Where, as happens
_ in fome inftances, the ftones contained in the
_ veins have no affinity to any of the rocks above,
_ they cannot be fuppofed to have come any how
_ but from below, and to have been carried up by
_ the matter of the vein. ‘The inftance from the
4 flip at the Muodonfieid Canal has been already
-= mentioned.
232. The preceding obfervations have been
4 d principally directed againft that theory of veins
PE os pome them to have been filled by de-
; A pofition

258 ILLUSTRATIONS OF THE

pofition from water. There is another theory
maintained by fome of the Neptunifts, that the
metals in veins were introduced there by infil.
tration *. ‘This opinion is fufficiently refuted
by the fad, that rarely any metallic ore is found
out of the vein, or in the rock on either fide of
it, and leaft of all where the vein is richeft,
This is inconfiftent with the notion of the ore
being carried into the vein by water percolating
through the adjacent rocks, unlefs fome fatisfac-
tory reafon is afligned, which determined the
water to leave the ore in the vein and no where
elfe. Befides, this hypothefis does not account
‘or the formation of the fpars and veinftones
which fill the vein, and which appear clearly to
have been brought there at the fame time with
the ore, and no doubt by the fame caufe.

233. The veins, properly fo called, are inde-
finitely extended ; but there are alfo thin plates
of fpar, and of cryftals of different kinds, often
found included in rocks, and fhut in on all fides,
to which the name of veins is commonly ap-
plied. Thefe laft ought certainly to be diftin-
guifhed from the former, and may not impro-
perly be called Plate Veins or Lenticular Veins,
the plate or cake of {par of which they confift
having very often the form of a lens, though,

as

* Geol. Effays, p. 401.

HUTTONIAN THEORY. 259°

as may be fuppofed, confiderably irregular. Ei-
ther of thefe terms being derived entirely from
external characters, has the advantage of in-
volving nothing theoretical.
herp The lenticular veins are certainly not formed
is like the ufual mineral veins, by inje@ion, fince
fy) they are fhut in, on all fides, by the folid rock.
When they are found, therefore, in ftratified
_ rocks, fuch as have not themfelves been melted,
we muft conceive them to be compofed of ma-
terials more fufible than the furrounding rock,
| fo that they have been brought into fufion by a _
|.) degree of heat which the reft of the rock was
a able to refift, and, on cooling, have affumed a
: {parry ftruGure. When they are found in
À rocks, of which the whole has been fluid, they
~ Ò muft be confidered as component parts of that
= maf, which, by an eleđtive attraction, have
united with one another, and feparated them-
{elves from the fubftances to which they had
Eee anity. = ——
E The veins of this kind feem to be connected
_ With thofe called in Derbythire Pipe Veins, in
| Which the ores of metals are fometimes found.
i The pipe veins, indeed, are not in all cafes com-
7 pletely infulated, but fometimes communicate
with the veins properly called mineral. I am
4 too little acquainted, however, with their natu-
Tal hiftory, to ‘be able to fay with certainty to
R2 which

TTEA

260 ILLUSTRATIONS OF THE

which of the two fpecies they ought to be re.
ferred.

Note xiv. § 75.

On W. hinftone.

234. To the facts and reafonings given above,
I fhall, in this note, add a few remarks, tending
to fhew, that whinftone is not of volcanic, nor
of aqueous, but certainly of igneous origin.

It is afferted (§ 62.), that carbonat of time and
zeolite aré often contained in whinftone, but ne-
ver in lava, and that this circumftance may fome-
times ferve to diftinguifh thefe ftones from one
another. With refpect to carbonat of lime, in par-
ticular, it feems evident, that this fubftance can-
not enter into the original compofition of any la-
va, becaufe the fame heat which melted the lava, -
would, where there was no greater preffure than
the weight of the atmofphere, expel the carbo-
nic acid and produce quicklime. Notwithftand-
ing this, rocks, containing carbonat of lime, have
often been confidered as lavas, into the pores
and cavities of which, calcareous matter having
been carried by the infiltration of water, had

cryftallized into fpar. Thus SPALLANZANI,
in.

HUTTONIAN THEORY. 261

in his account of the Euganean Hills, in Lom-
bardy, defcribes fome of the rocks as abound-
ing at their furface, and even in th-ir interior,
with air-bubbles of various fizes, from uch as
are hardly perceptible, to fome that are half an
inch in diameter ; and which, he fays, are all of

et

the fame direCtion. This he confiders as a proof
| that the rock is a genuine lava; for the air-
_, bubbles prove the ftone to have had its fluidity
_ from fire; and by their elongation in the fame
- direction they prove, that the mafs when fluid
a = was alfo in motion. Spallanzani adds, that ma-
“= ny of thefe cavities are filled with cryftals of the
yl carbonat of lime, an effect of the infiltration of
"quater *, :
: 235. Though the argument here advanced
e for the igneous origin of the rock may be admit-
me ted as conclufive, the introdu&tion of calcareous
a {par into it by infiltration muft ftill be que-
‘ftioned. Lava, except in a ftate of decay or de-
compofition, is not readily penetrated by water ;
and, if it were, the filling of cavities with fpar,
A By means of the water percolating through them,
i’ Would fill be fubject to many difficulties, (§ 12.).
a Befides, whinftone rocks are frequently found
R 3 fo

* Voyages dans les deux Siciles, tom. iii. p. 157.

3 f Edit. de Faujas de St Fond.

an oval figure, with their longeft diameters in -`

F

262 ILLUSTRATIONS OF THE

fo full of calcareous fpar, or of zeolite, that they
would become porous to fuch a degree, if the
cavities filled with thefe latter fubftances were
all empty, that they could hardly fuftain their
own weight, and much lefs that of the great maffes
of rock incumbent on them. In fuch cafes, it jg
certain, that the cryftallized fubftances were part
of the original compofition of the rock. The

truth is, that the infiltration of the water is a mere

gratuitous aflumption, introduced for the pur-
pole of explaining the exiftence of carbonated
lime in a tone which had endured the ation of
intenfe heat; and this aflumption ought of
courfe to be rejected, if the phenomenon can be

explained by a theory, that is in other refpeds

conformable to nature. The fpar, then, may
be confidered as a proof, that the rocks in que-
fion are to be numbered with thofe unerupted
lavas which have flowed deep in the bowels of
the earth, and under a great comprefling force,
This is the more probable, that the Euganean .
Hills, like fome whinftone hills in our own coun-.
try, have, in certain places, a covering of flaty
and calcareous firata incumbent on them, even
at their fummits *, fo that the torrent of melted
Rone, of which they are admitted to confiff, can-
not have flowed from the mouth of avolcano. Ido

| not

* Phil, Tranf. 1775, p. 34;

HUTTONIAN THEORY. 263

not mean to fay, that there are among thefe
hills no veftiges of volcanic explofion. I am
f yery far from having data fufficient for drawing
this conclufion ; but I believe it may be fafely
affirmed, that the bulk of them is no more com-
pofed of volcanic lava, than the bafaltes of Staffa,
or of the Giant’s Caufeway.

236. But, befides the evidence deduced from
= calcareous {par and zeolite, againft the rocks
containing them being real lava, there are other
- marks, even lefs equivocal perhaps, that diftin-
guifh the lavas which we fuppofe to have flow-
4 ed in the mineral regions, from thofe which
have actually flowed on the furface. Thefe are
what we colle from the difpofition, the orga-
nization, or, as we may fay, the phyfical geogra-
phy of whinftone countries, unlike, in fo many re-
{pects, to that of volcanic countries. The fhape
of whinftone hills ; their large flat terraces, rifing
one above another ; their perpendicular faces,
and the correfpondence of their heights even at
confiderable diftances ; have nothing fimilar to
them in the irregular torrents of volcanic lavas.
_ «The phenomena of the former are alfo on a fcale
_ of magnitude very far exceeding the latter, and
_ Clearly indicate, that though both have been
_ produced by fire, it has been by fire in very dif-
ferent circumftances, and regulated by very dit-
ferent laws. The ftructure of the two kinds of
E. R4 rock

264 ILLUSTRATIONS OF THE.

rock agrees, in many refpects, and fo does their

chemical analyfis ; but their difpofition and ar.
rangement are fo diffimilar, that they cannot be
fuppofed to be of the fame formation.

237. This argument, I believe, was firft fta.
ted by Mr Srranes, in a letter to Sir Joun
PRINGLE, publifhed in the 65th volume of
the Philofophical Tranfactions *, That intelli-
gent obferver, after vifiting the countries in Eu
rope moft remarkable either for burning, or for
what are accounted, extinguifhed volcanoes, and
examining them with a very difcriminating eye,
remained convinced, that there are two difting
fpecies of rock, which both owe their origin
to fire; but to fire aGing in circumftances and
feats extremely different. The firft is the
common volcanic lava; the other, to which he
gives the name of a bafaltine rock, comprehends
fuch rocks as the Giant’s Caufeway, the bafaltes

of the Vivarais, of the Euganean Hills, &c. and ©

differs in nothing from that which is called here
by the name of whinftone. Mr Strange con-
ceived, that the one of thefe kinds of ftone could,
no more than the other, be accounted the work
of aqueous depofition, but was led to the diftinc-
tion juft mentioned, by obfer ving the organization

and

* Account of Two Giants Caufeways in the Vene-
tian State, &c. by John Strange, "Efq; Phil. Tranf,
vol. lev: (1775.) p. 5, &e,

a]

HUTTONIAN THEORY. 265

and arrangement in the rocks of the latter kind,

_ and comparing them with the diforder and ruin

` that every where mark the footfteps of volcanic
fire. He does not pretend to determine the nature
of the fire to which the bafaltine rocks owe their
formation, nor the circumftances in which it has
acted: he is fatisfied with the negative conclu-
fion, that it is not volcanic ; and his paper affords
a fpecimen of what is perhaps rare in any of the
A fciences, and certainly moft rare of all in geolo- —
gy, viz. a philofophic induction carried juft as
far as the facts will bear it out, and not a fingle
ftep beyond that point.

238. Several other hints contained in this pa-
per are highly deferving of notice; for we not
= only find in it the nétion of a formation of ba-
= faltic rocks, igneous though not volcanic, but
alfo that of their fimultaneous cryftallization *,
together with the fuggeftion, that granite and
= bafalt are of the fame origin +. Thefe opi-
= nions had not, I believe, occurred at that
time to any mineralogift except Dr Hutton, nor
_ had they been communicated by him to any but
a few of his moft intimate friends; fo that Mr
Strange has without doubt all the merit of a firit
difcoverer. Indeed, without the knowledge of

the

# Phil, Tranf. abi fupra, p. 17.
+ Ibid. p. 36. and 37.

266 ILLUSTRATIONS OF THE

the principle of compreffion, fuch as it is laid
down by Dr Hutton, it was hardly poflible for
him to proceed further than he has done. He
remarked the usburnt limeftone that lies on the
tops of fome of the Euganean bafaltes, and feems
to have been aware of the great difficulty, which
it was referved for the Huttonian Theory to over.
come. His letter contains alfo fome excellent
general remarks on the rocks of the Vivarais
and Velay, which he had vifited, before Fauyas
pE ST Fonn had publithed his curious and ela.
borate defcription of thefe countries.

239. The caufe of the peculiar ftru@ure which

has juft been obferved to diftinguith whinftone
from volcanic countries, is ealily afligned in the
Huttonian Theory. According to that theory, the
whinftone rocks were formed, in the bowels of
the earth, of melted matter poured into the rents
and openings of the ftrata. They were caf,
therefore, in thofe openings, as in a mould; and
seceived the impreffion and charaéer of the
rocks by which they were furrounded. Hence
the tabular maffes of whinftone, which when
foft have been interpofed between ftrata, and
comprefled by their weight, fo as almoft to have
themfelves acquired the appearance of ftratifica-
tion. Hence the perpendicular faces of the fame
rocks, produced by their being abutted when

yet

————— E E E

HUTTONIAN THEORY. 267 `

yet foft, againft the abrupt fides of the ftrata.
The rocks which formed thofe moulds have, in
many cafes, entirely difappeared ; in others, a
part ftill remains, furrounding, or even covering,
the bafaltes, as in the Euganean Hills, in thofe
of the Val di Noto in Sicily, the rocks near
Lifbon *, and in different parts of Great Britain.
- Above all, the veins of whinftone which in-
terfect the ftrata, are the completeft proofs of

M the theory here given of thefe rocks, and the |

moft inconfiftent, in all refpects, with the hypo- ~

thefis of their volcanic origin.

| 240. If thefe criteria are applied to what are
- called extinguifhed volcanoes, I have no doubt
that many which have been reckoned of that
number, will be found to derive their origin
more directly from the fire of the mineral re-
gions. The bafaltic rocks of the Vivarais, I am
well perfuaded, belong to this clafs ; and I con-
clude that they do fo, not only from the account
of them given by Mr Strange, but from the de-
{cription of Faujas himfelf, who, though under

g the influence of the oppofite theory, feems very

fair and accurate in his defcription of pheno-
mena. The moft unequivocal mark of real
whinftone rock, and of a formation in the ftrict-

eft

i A Te far les Volcains Eteints du Vivarais;
Lettre de ao P> 443.

268 ILLUSTRATIONS OF THE

eft fenfe mineral, is where veins of that kind of
rock interfect the ftrata. Now, ina letter tg
Buffon, on the ftreams of lava found in the ip.
terior of certain calcareous rocks in the lower
Vivarais, Faujas defcribes what can be account.
ed nothing elfe but a vein or dike of whinftone,
accompanied with feveral of its moft remarkable
and characteriftic appearances: ‘ Figurez-vous
un courant de lave, de la nature du bafalte noir,
dur et compacte, qui a percé a travers les maffes
calcaires, et s’eft fait jour dans quelques parties,
paroiffant et difparoiflant alternativement : Cette
coulée de matiére volcanique s’enfonce fous une
partie de la ville, bâtie fur le rocher ; elle re-
paroit dans la cave d’un maréchal, fe cache et
fe montre encore de temps en temps en defcen-
dant dans le vallon, &c. Ce qu’il y a d’admi-
rable, c’eft que la lave forme deux branches
bien extraordinaires, dont l’une s’éleve fur la
crête du rocher, tandis que lautre coupe hori-
zontalement de grands bancs calcaires efcarpés,
qui font à découvert, et bordent le chemin,
o Quels efforts n’-a-t-il pas falla pour forcer
cette lave fe prendre une telle dire&tion, et fe
percer cette fuite de rochers calcaires? Si cette
longue coulée de lave avoit eu 200 ou 300 toifes
de largeur, je ne ferois pas furpris qu’un tor-
rent de matière en fufion de ce volume eut pu
produire des effets extraordinaires et violens ;
mais

y

M

| wonder that he confidered as marvellous what is

HUTTONIAN THEORY. 26g

mais figurez-vous, Monfieur, que dans les en-
droits les plus larges, elle wa tout-au-plus qu en-
viron 12 ou 15 pieds ; elle wen aque 3 ou 4 dans
certaines parties *.”’ 3

This narrow ftream is to:be traced acrofs the
ftrata for more than a league and a half; and

‘ the whole appeared to Faujas fo marvellous, that

he fays he almoft doubted the teftimony of his

q fenfes. He would have done much better, how-
® ever, to have doubted the conclufions of his

theory ; for it was by them that the phenomena
before him were rendered fo mytfterious and in-
credible. While he continued to regard what
is defcribed above as a ftream of melted lava,
which had defcended from the top of one moun-
tain, and climbed up the fides of the oppofite,
like water in a conduit pipe, piercing occafion-
ally through vaft bodies of folid rock, it is no

indeed phyfically impoffible. Had his belief in
the volcanic theory permitted him to fee in all
this, not a fuperficial current, but one of inde-
finite depth, he would have beheld the object
divefted, not of what was curious and interett-
ing, but of what was incredible or abfurd,
and reduced to the fame clafs of things
With mineral veins. That it belongs really to
this clafs, and is no more than a vein or dike

of

* Volcains Eteints du Vivarais, p. 328, &c.

270 ILLUSTRATIONS OF THE

of whinftone, interfeting the ftrata to an un.
Known depth, and moft probably, like other
veins, com icating with the mineral regions,
cannot be doubted by any one who has ftudied
the fubject of bafaltine rocks, through any other

medium than the volcanic theory. The rami-

fications which run from it into the calcareous
rock, contrived, Faujas fays, juft as if on purpofe
to perplex mineralogifts, is one of the well
Known and charaéteriftic appearances of bafal-
tic veins. |
241. It can hardly be doubted, that the lava

defcribed by the fame author as heaving up’

a mals of granite¥, and including pieces of
it, is a rock of real whinftone. The fame
may be faid of many others; and, though I
pretend not to affirm that there is nothing vol-
canic in the Vivarais, I muft fay, that nothing
decidedly volcanic appears in the defcription of
that country, but many things that are certainly
of a very different origin.

In the prefent ftate of geological fcience, a
fkilful mineralogift could hardly employ him-
{elf better, than in traverfing thofe ambiguous
countries, where fo much has been afcribed to
the ancient operation of volcanic fire, and mark-
ing out what belongs either clearly to the erupt-

ed

sname

* Volcains Eteints du Vivarais, fol. p. 365, &c.

HUTTONIAN THEORY.’ 291

ed or unerupted lavas, and what parts are of

doubtful formation, containing no mark by
which they may be referred to the one of thefe
any more than to the other. Such a work would
contribute very materially to illuftrate the natu-
ral hiftory of the earth. .

242. One of the moft ingenious attempts to

“fapport the volcanic theory, is the fyftem of |

MN fubmarine volcanoes, imagined by the celebrated

pi - mineralogit Doromrru. The phenomenon that

. | Ted to this hypothefis, was what he had obferved

„in the hills near Lifbon, and ftill more remark-
_ ably in thofe of the Val di Noto in Sicily, where

the bafaltine rocks had regular ftrata incumbent
on them, and in fome cafes interpofed or alter-
nated with them *. It feemed from this evi-
dent, that the ftrata were of later formation than
the ftone on which they refted; and as they
muft, on every fuppofition, be held to be depo-
fited by water, it was~concluded, that the lava
which they covered had been thrown out by
volcanoes at the bottom of the fea; that the

ftrata had afterwards been depofited on this la-

va; and that, in fome cafes, there had been fre-
quent

* Mémoire de Deodate de Dolomieu, fur les Vol-
cains Eteints du Val di Noto, en Sicile. Journal de,
Phyf. tom. xxv. (1784. Septembre.) p. 191.

232. ILLUSTRATIONS OF THE

‘quent alternations of thefe eruptions and depo.
fitions *,

243. Though this hypothefis does certainly
deliver the fyftem of the Volcanifts from one
great difficulty, it is itfelf liable to infurmount.
able objections. I fhall juft mention fome of
the principal.

x. The regular and equidiftant ftrata that
we often fee covering the tops of whinftone
or bafaltic rocks, could not have been depofited
in the oblique and very much inclined pofition
which they now occupy.

į
This is remarkable in the ftrata which cover

the bafaltic rock of Salifbury Craig, near Edin-
burgh, at its northern extremity. The ftrata
are very regular, and muft have been depofited

in a plane nearly horizontal; yet the furface of

the bafaltes on which they now reft is very much
inclined, dipping rapidly to the north-eaft. The
neceflity of a horizontal depofition in ftrata,
which, though not now horizontal, have their

planes

—

* Near Vizini, in the Val di Noto, Dolomieu tells
us, that he counted eleven beds, alternately calcareous
and volcanic, in the perpendicular face of a hill, which
at a diftance appeared like a piece of cloth, ftriped black
and white; uz fupra. In another inftance he faw more
than twenty of thefe alternations. He has fince made
fimilar obfervations in the Wincentine and in Tirol.
Journal de Phyf. tom, xxxvii. (1790), partie 2. p. 200.

HUTTONIAN THEORY. 2493

S planes nearly parallel to one another, has been’

proved at § 38.
2, If there is any truth in’ the principles

I eftablifhed above, even the ftrata themfelves

have not been confolidated without the action
of fire. By Dolomieu’s fyftem, therefore, the
confolidation of the ftrata which cover the ba-
faltes is not accounted for.

3. There are no means furnifhed by the

" hypothefis of fubmarine volcanoes for bringing

the bafalt, and the ftrata which cover it, above

ee | _ the level of the fea. If it is faid that the waters

of the fea have been drained off, the objections
are all incurred that have been ftated at § 37 *.
If it is faid, that the rocks themfelves have been
elevated by a force, impelling them upwards, we

_ fay, that the exiftence of fuch a force, when
= admitted, furnifhes another means of explain-

ing the whole phenomenon, namely, that of the
injection of melted matter among the ftrata, the

# fame that is ufed in the Huttonian Theory.

4. The phenomena of balfaltic veins are not

| inthe leaft explained by the hypothefis of fub-

marine volcanoes. That hypothefis, then, even
if the foregoing objections were removed, does
3 not

* Dolomieu adopts this fuppofition ; he thinks,
that the furface of the fea muft have been formerly 509
Of 600 toifes above its prefent level. Thid. p: 196.

274 ILLUSTRATIONS OF THE

not ferve to explain all the facts refpecting the
rocks of this genus, and wants, of confequence,
one of the moft important characters of a true
theory. It muft be allowed, however, that it
m#kes a confiderable approach to fuch a theory,
and that the fubmarine voleanoes of Dolomieu, |
have an affinity to the unerupted lavas of Dr
Hutton.

244. Though in thefe remarks I have endea-
voured to expoie the errors of the volcanic fyftem,
I cannot but confider that fyftem as coming
infinitely nearer to the truth than the Neptu.
nian. It has the merit of diftinguifhing an or-
der of rocks, which bears no mark of aqueous
formation, and in which the cryftallized, fparry,
or lava-like ftructure, befpeaks their primeval
fluidity, and refers their origin to fire. The
Neptunian fyitem, on the other hand, ftrives to
confound the moft marked diftin@tion in the
mineral kingdom, and to explain the formation,
both of the ftratified and unftratified rocks, by
the operation of the fame element. Though —
chargeable with this inconfiftency, it has be-
c me the prevailing fyftem of geology ; and the
arguments which fupport it are therefore enti-
tled to attention.

245. It will no doubt be thought fingular,
that the fame mineralogift, whom we have jut
feen exerting his ingenuity in defence of the

volcani¢

I Egyptian bafaltes. But there is no reafon why, `

HUTTONIAN THEORY. 275

volcanic fyitem, fhould now appear equally ftre-
nuous in defence of the Neptunian. Though
Dolomieu contends for the volcanic origin of
fome bafaltic rocks, he does not admit that all
bafaltes is volcanic, nor even all of igneous for-
mation. Thus he ftates, that he had examined
at Rome fome of the moft ancient monuments
of art, executed in baialtes, brought from Upper

T Egypt, and that he could difcover n mark of
Mm the action of fire in any of them *. On the

contrary, he found that fome of them confift-
ed of green bafaltes, which changes its colour
to a bronze, when expofed even to a mo-
derate heat, and which therefore, he argues,
can never have endured any ffrong ation of
fire, }

The anfwer to this argument is very plain, if
we admit the effects afcribed by Dr Hutton to
the compreffion which neceflarily takes place in
the mineral regions. If indeed the heat in thofe
regions refemhled exa&ly that of our fires at
the furface, it would not be eafy to deny the
above conclufion, which therefore certainly
holds good againft the volcanic origin of the

under {trong compreffion, the colouring matter
5 2 j of

m ih

* Journal de Phyfique, tome XXXVilg ioo .) partie 2.
#193.

$
ie

‘

276 ILLUSTRATIONS OF THE

of thefe ftones might not be fixed, and inde
ftrudible by heat, though it can be eafily vola.
tilized or confumed when fuch comprefiion is
removed. This argument then is againft the
volcanic ; but not againft what has been called
the Plutonic formation of bafaltes.

246. As to the other marks of fire which Do-
lomieu fought for and did not find in the above-
mentioned ftones, we are not exa@ly informed
in what they confifted. If the cryftallized or
{pathofe texture that belongs to this defcription
of ftones was wanting, the {pecimens were not
to be confidered as of the real bafaltie or whin-
itone genus, whatever their name or hiftory may
feem to indicate. If they did poffefs that tex-
ture, they had the only mark of an igneous ori-
gin that could be expected, fuppofing that ori-
gin to have been in the bowels of the earth.
No part, therefore, of the obfervations of this
ingenious mineralogift, can be confidered as in-
confiftent with the theory of bafaltic rocks
which has been laid down above.

247. Bergman had before reafoned on this
fubject precifely in the fame manner, but from
better data, as the ftones from which he deri-
ved his argument were in their native place:
“ Trap,” fays that ingenious author, (that is,
whinftone), “ is found in the ftratified moun-
tains of Weft Gothland, in a way that deferves

to.

+HUTTONIAN THEORY. 207

to be defcribed. The lower flratum, which is

-feveral Swedifh miles in circuit, (10% of thefe

miles make a degree), is an arenaceous ftone,
horizontal, refting on granite, and having its

particles agglutinated by clay. The ftratum

above this is calcareous, full of the petrifaGtions
of marine animals, and above this is the trap.
Thefe three kinds of rock compofe the greater

part of the mountains juft mentioned, though

there are fome other beds, particularly very thin
beds of marl and of clay, which feparate the
middle ftratum, both from that which is under
it and over it, and are frequently fo penetrated
with bitumen that they burn in the fire. This
{chiftus is black ; when burnt it becomes red,
and afterwards, when wafhed with water, af-
fordsalum. How can it be fuppofed,”’’ he adds,

“that the trap has ever been violently heated,

while the {chiftus on which it is incumbent re-
tains its blacknefs, which however it lofes by
the action even of a very weak fire *.”’

The anfwer to this argument is already given.
The reafoning, as in the former inftance, is con-
clufive only againft the action of volcanic fire,
or fire at the furface ; but not againft the action
of heat deep in the bowels of the earth, and un-

9 3 der

* Bergman de Produétis Volcaniis Opufcula, tom. ili.
Pp 214, &c,

278 ILLUSTRATIONS OF THE

der the preffure of the fuperincumbent ocean,
In fuch a fituation, the bituminous {chiftus
might be in contact with the melted bafalt, and
yet there might be no evaporation of the vola-
tile, nor combuftion of the inflammable parts,
It does not, however, always happen, that the
bituminous fubftances, or fubftances alterable by
fire, which are found in contaét with bafaltes,
are without any mark of having endured the
operation of fire. Inftances in which fuch
operation is apparent are given above, § 30. ;
and more will be added in the conclufion of this
note. —

248. The fame mineralogift founds another
argument for the aqueous formation of whin or
trap, on the exiftence of that ftone in the form
of veins, included in primeval rocks: “ Inveni-
tur hoc faxum (trap) in Suecia pluribus locis,
feepeque in montibus primevis, anguftas implens
venas, adeo fubtilis ftruGture, ut particule fint
impalpabiles, et, dum niger eft, genuinum efficit
lapidem Lydium. In hifce montibus, nulla ad-
funt ignis fubterranei veftigia *.”

The phenomenon here defcribed, namely, a
vein of compa@ whinftone traverfing a primary
rock, is, without doubt, as incapable of being
explained by the operation of a volcano, as it is

By

* Opufcula, ubi fupra,

< HUTTONIAN THEORY. 279
by that of aqueous depofition. It is, however,
a moft complete proof of the original foftnefs of ©
the fubftance of which the veins confit, and af-
fords one of the ftrongeft poflible arguments for
fuch an operation of fire as is fuppofed in the
prefent theory. The main arguments, there-
fore, which have been propofed as fubvertive of
the igneous origin of bafaltes, are only fubver-

| = five of their formation by one’ modification of

fire, viz. of fire acting near the furface; and
thus the weapons which directly pierce the ar-
mour of the Volcanift, and infli@ a mortal
wound, are eafily turned afide by the fuperior

temper of the Plutonic mail.

249. An argument founded on facts very fi-
milar to fome of the preceding, and leading to
the fame conclufion, is employed by the mine-
ralogift to whom the Neptunian fy{tem owes its
chief fupport. Werner, in his obfervations on
volcanic rocks and on bafaltes, has refted his
proof of the aqueous formation of the latter, on
their interpofition between beds of ftone in
mountains regularly ftratified, and obvioutly
formed by water. He defcribes an inftance of
this in the bafaltic hill of Scheibenberg ; and the-
facts, though moft of them are not uncommon,

are highly deferving of attention. Near the
top of this hill, and above the bafaltic rock
_ which compofes the body of it, he tells us, that

wae there

280 ILLUSTRATIONS OF THE

there was a fand-pit; a cir {tance which he ©
appears to confider as not a little fingular. It
was, however, at the bottom of the hill, that he
met with the appearances which chiefly attra@.
ed his notice: “ Firft,” fays he, “or loweft,
was a thick bank of quartzy fand, above thata.
bed of clay, then a bed of the argillaceous ftone
called wacken, and upon this laft refted the ba-
faltes.” “ When I faw,” adds he,“ the three firk
beds running almoft horizontally under the ba-
faltes, and forming its bafe; the fand becoming
finer above, then argillaceous, and at laft chang-
ing into real clay, as the argil was converted in-
to wacken in the fuperior part; and, laftly, the
wacken into bafaltes: ina word, when I found
a perfect tranfition from pure fand to argilla.
ceous fand, from the latter to a fandy clay, and
from this fandy clay, through many gradations,
toa fat clay, to wacke, and at laf bafaltes, I
was irrefiftibly led to conclude, that the bafaltes,
the wacke, the clay, and the fand, are all of one
and the fame formation; and that they are all
the effect of a chemical precipitation during one
and the fame fubmerfion of this country *.”
i Firft,

* «Combien je fus furpris de voir en arrivant au fond,
un épais banc de fable guartzeux, puis an-deflus une
couche d’argile, enfin une couche de la pierre argileufe
nommée Wacke, et fur celle-ci repofer le bafalte, Quand

| je

HUTTONIAN THEORY. (285

tic hill, it is moft probably the remains of cer-
tain fandftone ftrata that originally covered the
bafaltic part, but are now worn away. We are
_ therefore to confider this as an inftance of a ba-
faltic rock, interpofed between {trata that are
undoubtedly of marine origin. In this, how-
l. fuer, there is nothing inconfiftent with Dr Hut-
Taa theory of bafaltes; on the contrary, it is
one

fe je vis les trois premières couches s'enfoncer prefqw bori-
gontalement fous le bafalte, et former ainfi fa bafe; le fable
devenir plus fin au-deffus, puis argileux, et fe changer
enfin en vraie argile, comme Vargile fe convertiffoit en
wacke dans fa partie fup¢rieure ; et finalement la wacke
en bafalte: en un mot, de trouver ici une tranfition par-

Sabloneuje, et de L'argile fabloneuf', par plufieurs grada-
tions, à Purgil gri fe, Ala wacke, et enfin au ba/alte.
A cette vue, je fus fur-le- champ et irréfiftiblement
entrainé à penfer, (comme lauroit été -fans doute tout
` connoiffeur impartial frappé des conféquences de ce
~ ph nomène); je fus, dis-je, irréfiftiblement entrainé aux
“Ades fuivantes: Ce bafatte, cette wacke, cette argele, et
ce fable. font d'une feule et méme formation ; ils font tous
Veflet dune precipitation par voie bumide dans une feule
et même fubmerfion de cette contrée; les eaux qui la
_ Couvroient alors tranfportoient d’abord le Jable, puis de-
Pofoient l'argile, et changoient peu-d-peu leur précipita-
tion en wacke, et enfin en vraie bafalte.” — Journal de
Phyfique, tome xxxviii. (1791), partie 1. p. 415.

Firft, as to the fand on the top of this bafal-

fat du fable pur au fable argileux, de celui-ci a /’argile

282 ILLUSTRATIONS OF THE

one of the principal facts on which that theory
is founded. It has indeed been argued by fome
mineralogifts, that bodies thus contiguous muĝ
owe their origin to the fame element, and that
a mineral fubftance cannot be of more recent
formation than that which lies above it. But
the maxim, that a foffil muft have the fame
origin with thofe that furround it, does not
hold, unlefs they have a certain fimilarity of
ftructure. It is, for inftance, the want of this
fimilarity, that authorifes us to affign different
periods of formation to mineral veins, and to
the rocks in which they are included.

In a fucceflion of ftrata, no one can doubt,
that the loweft were the firft formed, and the
others in the order in which they lie; but, when
between two ftrata of fanditone or of limeftone
we find an intermediate rock, fo different as to
refemble lava, and to have nothing f{chiftofe or
{tratified in its compofition, the fame inftrument
cannot be fuppofed to have been employed in
the formation of both; nor is there any reafon
why we may not fuppofe, that the intermediate
body was interpofed between the other two, by
fome aétion fubfequent to their formation. It
was thus that Dolomieu concluded, when he
faw a lava-like ftone interpofed between calca-
reous firata in the Val di Noto, that, though

contiguous,

HUTTONIAN THEORY. 283

contiguotis, thefe two rocks could not poffibly
. be of the fame formation ; and thus far it is cer-
tain, that every unprejudiced obferver muft agree
m | With him. |
250. But the circumftance on which Mr Wer-
‘ner feems to lay the greateft ftrefs, is the gra-
© dual tranfition from the fand to the bafalt,
“| through the intermediate fteps of clay and
at i wacken ; this gradual tranfition he confiders
th r asa direct proof, that they are all of the fame
_ formation.
_ A gradual tranfition of one body into another,
can only be faid to take place, when itis im-
} poflible to define their common boundary, or to
aj determine the line where the one begins and the
i other ends. Now, if this be the proper notion
ine of gradual tranfition, I mutt fay, that after much
tf careful examination, I have never feen an
j inftance, in which fach a tranfition takes
i place between whinftone and the contiguous
E frata. The fine of feparation, though in fome
' places lefs évident than in others, has, on the
i whole, been marked out with great precifion ;
and, though the ftones have been firmly united,
OT, as one may fay, welded’ one upon another,
| yet, when a freh fratture was obtained, the
sh - ftratified and unttratified parts have rarely failed
jf to be diftinguithed. The freth fracture is in-
| deed often neceflary, for many fpecies of whin-

{tone

284 ILLUSTRATIONS OF THE

ftone get by decompofition a granulated texture
at the furface, fo as hardly to be diftinguithed
from real fandftone.

Some of the kinds of primary fchiftus alfo, par-
ticularly the argillaceous, when much indurated,
have in their ftructure a confiderable refemaieal

to whinftone ; they are flightly granular, or la.

minated, and A ave a tendency toa fparry texture,

Where it happens that this fort of {chiftus and

whinftone are contiguous, it is natural to expect,
that their common boundary will be traced with
difficulty, and in many parts will be quite un-
certain. Still, however, if a careful examination
is made; if the effects of accidental caufes are
removed ; and, above all, if the more ambiguous
inftances are compared with the more decifiye,
and interpreted by them, though fingle fpeci-
mens may be doubtful, we will hardly ever find
that any uncertainty remains with re{pect to en-
tire rocks.

251. This general fact, which I ftate on much
better authority than that of my own obferva-
tions, viz. on thofe of Dr Hutton, is not given
as abfolutely without exception. The theory
of whinftone which has been laid down here,
leads us indeed to look for fome fuch exceptions.
It is certain, that the bafis of whinftone, or the

material out of which it is prepared by the ac-
tion

es

HUTTONIAN THEORY. 285

: tion of fubterraneous heat, is clay in fome ftate
or other, and probably in that of argillaceous

iy ; fchiftus. It follows, of confequence, that ar-
in gillaceous {chiftus may by heat be converted in-

to whinftone. When, therefore, melted whin-

~ fone has been poured over a rock of fuch fchif-

i q tus, it may, by its Heat, have converted a part of
A that rock into a ftone fimilar to itfelf; and thus
may now feem tobe united, by an infenfible grada-
tion, with the ftratum on which it is incumbent ;
and phenomena of this kind may be epee
to have really happened, though but rarely, as a
particular combination of circumftances feems
_neceffary to produce them. Hence it is evident,
_ that ftones may graduate into one another, with-
out being of the fame formation ; and that it is
fallacious to conclude, from the infenfible tran-
fition of one kind of rock into another, without
4 any other circumftance of affinity, that they have
both the fame origin.

I am difpofed, therefore, to make fome limi-
tation to what is faid in § 72, where I have ex-
preffed an abfolute incredulity as to fuch tranfi-
tions as are here referred to. The great fkill Eee,
and experience of the mineralogift'who has de-
{eribed the ftrata at Scheibenberg, do not al-
low us to doubt of his exactnefs, though fome
of the appearances are fuch as decompofition
and wearing might well enough be fuppoted to
produce.

206 ILLUSTRATIONS OF THE

produce. The faireft way is to take Mr Wer.
ner’s obfervations juft as they are given us, and
to try whether they cannot be explained with.
out the afliftance of his theory. In effe@,
the wacken which he defcribes, refts, it would
feem, on an unconfolidated bed of clay ; and
it may be fuppofed, that a part of this bed
has been converted into wacken by the heat of
the incumbent mats, and has thus produced the

apparent gradation from the one fubitance to
the other. As the appearances of the rocks of —

Scheibenberg feem to be confidered by Werner
as furnifhing a very ftrong, and even an unex-
pected confirmation of his fyftem, I cannot help
thinking, that an explanation of them, on the
principles of Dr Hutton, without any ftraining

or forcing of thofe principles, contributes not a i

little toward extending the empire of the latter
over all the phenomena of geology.

252. Another fact, which has been much infift-
ed on of late, in proof of the aqueous formation
of bafaltic rocks, is that fhells are found in
them. Of the reality of this faé&, -however,
or at leaft of the inftances hitherto produced,
great doubts I think may be reafonably enter-
tained. The fpecimens of the fuppofed bafaltes,
with fhells included in them, that are chiefly
relied on, are found at Portrufh in Ireland,
a rocky promontory to the weftward of the
Giant’s Caufeway, ang feparated from it by 4

confiderable

HUTTONIAN THEORY. 287

confiderable body of calcareous ftrata. Some
of thefe fpecimens were brought to Edinburgh
= about a year ago, and. were fuppofed, I believe,
- to contain an irrefragable proof of the Neptu-
I pian origin of the bafaltic promontory where
they were found. 1 went to fee thefe fpecimens
| in company with Lord Webb Seymour and Sir
_ James Hall; and, on examining them carefully,

A we were all of opinion, that the ftones which

ul contained the fhells, or the impreffions of the

ii) fhells, were no part of the real bafaltes. They
| were all very compa, and had all more or lefs of

a filiceous appearance, fuch as that of chert;
Í they had nothing of a {parry or cryftallized ftruc-

i ture; their frature was conchoidal, and but
i flightly uneven. In twoof them, one of which
wer! Dore the impreffion of a cornu ammonizs, the {chif-

tofe texture might bediftin@ly perceived. A fpe-

| cimen which accompanied th>, but in which
pi there was no fhell, ferved very exacily to explain
4 the relation between thefe ftones and the true

bafaltes. Part of this {pecimen was a true ba-
q falt, and the reft a fort of hornftone, exadtly the

fame with that in which the fhells were, and
Not unlike t:e jafper that is under the whinftone
of Salifbury Crag, and in conta& with it; fo

i that on the whole it was evident, that the rock

containing the thells is the fchiftus or ftrati-
fied ftone, which ierves as the bafe of the ba-
faltes,

288 ILLUSTRATIONS OF THE

faltes, and which has acquired a high degree of
induration, by the vicinity of the great ignited
mafs of whinftone.

This folution of the difficulty has fince been
confirmed by obfervations made on the {pot by
Dr Hope, who difcovered two or three alterna.
tions of the bataltic rock, with the beds of the
{chiftus in which the fhells are contained.

233. This alfo explains fome obfervations-of

Spallanzani, made in the ifland of Cerigo, on the —

coaft of Greece, the Cythera of the ancients*,
The bafe of that ifland is limeftone; but it
abounds alfo in unftratified rocks, which the

Italian naturalift fuppofes to be of volcanic oris -

gin; but which, if I miftake not, we would re-
gard as whinftone, or perhaps porphyry; and
they are faid to contain oyfter-fhells and pec-
tenites of a large fize, perfe@ly mineralized.

Thefe petrifaGtions, however, Spallanzani fays, —

are not contained in the lava that has ae-
tually flowed, but in ftones which have only
endured a flighter action of fire. Without the
commentary afforded by the Portruth fpecimens,
it would be difficult to make out any thing very
precife from this defcription. By help of the
information derived from thofe {pecimens, we
may conclude, that the condition of the fhells

in

al

* Journal de Phyfique, tom. xlviii, (1798), p- 278:

HUTTONIAN THEORY. 280

in them, and in the rocks of Cerigo, is perfet-
ly alike; and that, in both cafes, the fhells
are involved in parts of the rock which are truly
© ftratified, but which have been, in fome degree,
| aflimilated to the bafaltes by the heat which
’ they have endured. Spallanzani would proba-
bly have ufed exaétly the fame terms which he
_| employs in {peaking of Cerigo, if he had been
» | _ required to defcribe the petrified fhells at Port-
W tuh.
U 254. In the inftances juft mentioned, the petri-
fied marine objeéts are not found in the real
whinftone ; but if they were found in it, when it
wilt’ borders on ftratified rocks containing fuch ob-
mll jeéts, the thing would not be at all furprifing,
i nor furnifh any argument againft the igneous
uai confolidation of the ftone. If a torrent of
| melted matter was poured in among the ftrata,
by a force which at the fame time broke up and
§ difordered thofe ftrata, nothing could be more
wi natural, than that this matter fhould contain
| fragments of them, and of the objects peculiar
„y to them. =
@ In one inftance, mentioned by Mr Strange,
al _ this feems a&ually to have taken place. Inthe
* | Veronefe, a country remarkable for a mixture
of limeftone ftrata, containing marine objeds,
with volcanic or bafaltine hills, he affures us,
that he had feen a mafs of ftone, which had
T evidently.

290 ILLUSTRATIONS OF THE

evidently concreted from fufion, in which the
marine foffil bodies, originally, as he fuppo-
fes, contained in the ‘ftrata, were perfectly di-
ftinguifhable, though varioufly disfigured *, Jt
may be, that in this, as in the foregoing exam.
ples, it was not real. bafaltes, or real lava, ‘which
contained the fhells, but- the conterminal rock;
but, fuppofing it to be as Mr Strange reprefents

it, there appears to be no inconfiftency between
the phenomenon, and the igneous origin of the

rock in which the fhells were included. Here,
however, it fhould be remarked, that the pre-
fence of great preffure, to prevent the conver-
fion of the fhells into quicklime, feems abfolute-
ly necefiary ; and that the phenomenon of thefe
bafaltic petrifaCtions, requires the application of
heat to have been deep under the furface of the
earth.

255. The phenomena we have been confider-
ing, have been felected as the moft unfavourable
to the igneous origin of bafaltic rocks; and we
have feen, that when duly examined, they are
not at all inconfiftent with it. We are now to
take a view of fome appearances, that feem quite
irreconcilable with the aqueous formation of
thefe rocks. |

Where

a eel

* Phil. Tranf, 1775, P: 25-

wl

HUTTONIAN THEORY. 291

Where whinftone rocks are found in mafies,
pounded by the ftrata, and infulated among
them, they fubje& the Neptunian fyftem to great
difficulties. For, fuppofing it true that this
- ftone may be produced by the precipitation and
ayh lization. of mineral fubftances diffolved in
water, yet it feems unaccountable, that this e£-
2 fe& has been fo local and limited in extent,
ten to be confined to an irregular figure
a few acres, while, all round, the fubftan-
ces depofited have had no tendency to cry-
Aallzaton, and have been formed into the
mmon fecondary ftrata. The rock of Sa-
E; Craig, for inftance, is a mafs of whin-
Rone, having a perpendicular face eighty or
ninety feet high toward the weft, and ex-
tending from north to fouth with a circular
tweep about goo yards. The whole of this rock
re pelts on regular beds of fecondary fandftone, not
rizontal, but confiderably depreffed toward
e north-eaft : the rock is loftieft in the mid-
! Bend decreafes in thicknefs toward each end,
terminating at its northern extremity in a kind
fwedge. It is covered at top, toward that ex-
femity, with regular beds of fandftone, per-
fimilar to thofe on which it is incumbent ;
and it is not improbable, that this covering os
erly extended over the whale.
E +2 Now,

292 ILLUSTRATIONS OF THE

Now, what caufe can have determined the co-
lumn of water, which refted on the bafe at prefent
occupied by this rock, to depofite nothing but
the materials of whinftone, while the water on
the fouth, weft, and north, was depofiting the
materials of arenaceous and marly ftrata ?
Wherefore, within this {mall fpace, was the pre-
cipitate every where chemical, to ufe the lan-

guage of Werner, while clofe to it, on either
i
fide, it was entirely mechanical? Why is there,

in this cafe, no gradation? and why is a mere
mathematical line the boundary between re-
gions where fuch different laws have prevailed?
Whence alfo, we may afk, has the bafaltic de-
pofite been abruptly terminated toward the
weft, fo as to produce the fteep face which has
juft been mentioned ? The operation of currents,
or of any motion that can take place in a fluid,
will furnifh no explanation whatever of thefe
phenomena; yet they are phenomena far from
being peculiar to a fingle hill; they are among
the moft general and characteriftic appearances
in the natural hiftory of whinftone mountains;
and a geological theory which does not account
for them, is hardly entitled to any confidera-

tion.
256. The bafaltic rock, juft defcribed, is alfo
covered, at leaft partly, with ftrata perfectly fimi-
lar

Po

A

a
E,

: pears altogether unaccountable, that after the
= water had done depofiting the materials of the
Mi l whin on the fpot in queftion, the former order
y 1 was fo quickly refumed, and a depofition of
My fand, and of the other materials of the ftrata,
DNI took place juft as before. All this is quite un-
f intelligible ; : and the principles of the Neptu-
‘nian fyftem feem here to ftand as much in need
of explanation, as any of the appearances which
‘they are intended to acccunt for.
_ 257. The unequal thicknefs, and great irre-
-gularity i in the furface of the whinftone mafs,
here treated of, and of many rocks of the fame
kind, is alfo a great objection to the notion of
their aqueous formation. This feems to have
been perceived by Werner, in the inftance of
the rocks formerly mentioned ; and he endea-
yours to explain it, by fuppofing, that much of
thefe rocks has been deftroyed by wafte and de-
-compofition, fo that an irregularity of their fur-
face, and want of correfpondence has been given
“to them, which they did not originally poffefs.
In the inftance of Salifbury Craig, however, we
have a proof, that the great irregularity of fur-
face, and the inequality of thicknefs, do not al-
_ Ways arife from thefe caufes. The thinneft part
E” that rock, toward its northern extremity, is
- T3 -knl

HUTTONIAN THEORY. 293

jar to thofe that lie under it. Now, it ap-

294 ILLUSTRATIONS OF THE

ftill covered by the ftrata in their natural place,
and has been perfectly defended by them from
every fort of wearing and decay. The cunei
form fhape, therefore, which this rock takes at
its extremities, and the great difference of its
thicknefs at them and in the middle, is a part
of its original conftitution, and can be attributed

to nothing cafual, or fubfequent to its confolida-

tion,

rocks, where an inequality of thicknefs, moft
unlike to what belongs to aqueous depofites, is
known to exift in beds of whinftone that are
till deep under the furface. Thus the toadftone
of Derbytfhire, even where it has a thick cover-
ing of ftrata over it, has been found, by the fink-
ing of perpendicular fhafts, to vary from the
thicknefs of eighteen yards to more than fixty,
within the horizontal diftance of lefs than a fur-
jong.. Nothing of this kind is ever found to
take place in thofe beds of rock which are cer-
tainly known to originate from aqueous depofi-
tion, and no character can more ftrongly mark an
effential difference of formation.

258. We have had frequent occafion to con-
fider the characters of thofe mafles of whinftone
which are fo often found interpofed between
ftratified rocks. Thefe have been found in ge-

neral very adverfe to the Neptunian fyftem ; and
two

‘4
The fame may be faid of many other bafaltic

=

HUTTONIAN THEORY. = 205

4 twoof them which yet remain to be mention-
: ed, are even more fo than any of the reft.
_ Where a bed or tabular mafs of whinftone is _

Biterpotea between ftrata, and wherever an op-
hia offers of feeing its termination, if the
_ ftrata under it are not broken, it may be re-

| = marked, that they do not abut themfelves bluff

nd abrupt againft the whin. “On the con-
ry, if we mark the courfe of the ftratum
which covers the whinftone, and of that

which is the bafe of it, we fhall find they
converge toward one another, the interpofed
_ mafs growing thinner and thinner, like a wedge.
_ When the latter terminates, the two former
: ‘come in contact, and have no ftratum interpo-
fed between them. Thus the roof and bafe of

the whinftone rock are contiguous. beds, that

_ appear as if they had been lifted up and bent, and

_ feparated by an interpofed mafs. Had the whole

: been an effect of fimultaneous depofition, the re-

gular ftrata muft have been abruptly terminated.

by the whin, like two courfes of different forts
f of mafonry where they meet with one another.

- 259. From this wedge-form of the whinftone
_maffes, and in general from the irregularity of
“their furfaces, another conclufion follows, fimilar

l to the preceding, and one which has been already
© mentioned. Where the furface of the interpo-

wa K

at «fed

296 ILLUSTRATIONS OF THE

fed mafs is greatly inclined to the horizon, the
ftrata which reft on this inclined plane, are ne.
verthelefs as exadtly parallel to that plane, and
to one another, as if they were really horizon-
tal. It is certain, therefore, that they were not
depofited on the fame inclined plane on which
they now reft; for, if fo, they would have been
ftill nearly horizontal, and by no means parallel

to the inclined fide of the whinftone. This fol- i

lows from the nature of aqueous depofition, as
already explained.

We have a remarkable inftance of the pheno-
menon here referred to, in the rock of Salifbury
Graig, of which mention has been fo often made,
and in which almoft every circumftance is uni-
ted, that can ferve to elucidate the natural hifto-
ry of bafaltte rocks. The north end of that
rock is in the figure of a wedge, with its in-
clined fide confiderably fteep, and covered by
ftrata of grit, perfectly regular, and parallel
to the furface on which they lie. The in-
fpection of them will convince any one, that
they were not depofited by the water, on a
bottom fo highly inclined as that on which they
now reft. They are of a ftructure very {chiftofe;
their layers very thin; fo that any inaccuracy of
their parallelifm would be readily obferved.
The appearances of the horizontal depofition of
thefe ftrata, are indeed fo clear, and fo impofli-

: ble

HUTTONIAN THEORY. 297

ple to be mifunderftood, that the followers of
LF. the Huttonian fyftem would not rifk much, if
they were to leave the whole theory of whin- —
- ftone to the decifion of this fingle fa@, and
fhould agree to abandon that theory altogether, if
the Neptunifts can fhew any phyfical or ftatical
principle, on which thé depofition now defcribed
can poflibly bave been made ; ; or will point out
he rule, by which nature has given a ftruGure
fe fo nicely ftratified to arenaceous beds depofit-
ed on a furface fo highly inclined. If no
a principle can be pointed out, though we
cannot conclude that the Huttonian Theory is
q tue, we certainly may conclude that the Nep-
-tunian is falfe.

260. Proofs of the igneous formation of whin-
Boss, ftill more direct, are derived from the
induration of the contiguous ftrata; from their
difturbance when interfeGted by veins of whin- `
ftone ; and from the charring of the coal which
happens to be in conta@ with thefe veins. Thefe
f confidered above at § 66, 67, &c.; and it
s particularly taken notice of at § 66, that pie-
“ces of fandftone are fometimes found as if floating
_in the whinftone, and, at the fame time, greatly
altered in their texture. One of the beft and
- moft unequivocal inftances of this fort which I
have feen, is to be found on the fouth fide of
; Arthurs Seat, near Edinburgh. The rock
E which

298 ILLUSTRATIONS OF THE

which compofes the upper part of the hill, op
that fide, is a whinftone breccia, fuch as we
have many examples of, and, I believe, very
much refembling what is called a lava brecciaty
by the volcanic geologifts. The ftony frag.
ments included in this compound mafs, are for
the greater part rounded; and fome of them

are of whinftone, others ‘of porphyry, ftrongly —

characterized by retangular maculz of feltfpar, _

and many feem to be of fandftone, but fo coñ-
fiderably altered, as to leave it at leaft difputa:
ble whether they really are fo or not. In one
part, however, where the face of the rock is
nearly perpendicular, a narrow ridge is feen
ftanding out from the reft, and of a different co-
lour, being more entirely covered with mofs
than the rock round about it, and, as may be
prefumed from that circumftance, lefs liable
to decompofition. On examination I found,
that this ridge does not confift of whinftone, but
of a very hard and highly confolidated fand-
fione. It appears to be the edge of a ftratum,
of the thicknefs of about nine or ten inches, and
of the height of fifteen or fixteen feet. It is not
perfectly ftraight, but flightly waved, its general
direction being nearly vertical; and it is on
both fides firmly embraced by the whinftone.
When broken, it appears that this fand-

ftone refembles in colour, and in every thing
but

put its greater confolidation, and more vitreous
‘ftru@ure, the common grit found at the bottom

of the hill, and over all the adjacent plain. |
è 261. If all thefe circumftances are put toge-
her, there appears but one conclufion that can
be drawn from them. We have here the ma-
nifeft marks of fome power which could lift up
is fragment of rock from its native place, di-
t at leaft feveral hundred yards from its pre-
fituation, place it upright on its edge, en-
compafs it with a folid rock, of a nature quite
heterogeneous to itfelf, and beftow on it, at the
fame time, a great addition of folidity and in-
a uration. If the mafs in which this ftone is
now imbedded, be fuppofed to have been once
‘in i fion, and forcibly thrown up from below,
it wading the ftrata, and carrying the fragments
ng with it, the whole phenomena now de-
ibed admit of an explanation, and all the cir-
mftances accord perfe&tly with one another ;
but, without this fuppofition, they are fo many
Aeparate prodigies, which have no connection
4 with one another, nor with any thing that is
i known. It is indeed impoflible, that the effects
of motion and heat can be more clearly expref-
fed than they are here, or the fubject in which
thefe powers refided more diftinétly pointed

HUTTONIAN THEORY. 299

300 ILLUSTRATIONS OF THE

262. The preceding fa&s being fufceptible
but of one interpretation, are on that account
extremely valuable. The phenomena of Salif.
bury Craig, near the fame place, are almot
equally free from ambiguity. The bafaltic
rock which forms that precipice, refts on are.
naceous or marly ftrata; and thefe, in their
immediate contact with the former, afford an

inftance of what is mentioned § 67, namely,
the converfion of the ftrata in fuch fitua-

tions into a kind of petrofilex, or even jafper,
‘The line which feparates the one rock from the
other, is, at the fame time, fo well defined, as,
in the eyes even of the moft determined Neptu-
nift, to exclude all idea of infenfible gradi
tion.

263. The fame rock affords fome remarkable
inftances of the difturbance of the ftrata conti-
guous to the whinftone. The beds of the for-
mer are bent upwards in feveral places; and,
at one in particular, form an arch, with its con-
vexity downward, fo as to make it evident, that
the force which produced this bending was di-
rected from below upwards.

264. It is, however, where whinftone takes
the form of veins, interfecting the ftrata, that
the induration of the latter is moft confpicuous.
The coaft of Ayrfhire, and the oppofite coaft of

Arran,

eS ee ae

” and abundance. The ftrata are, in ma-
ny inftances, fo reticulated by the veins, and
E eriad at fuch fmall diftances, that it
pe neceflary to fuppofe, that the fiffures

up. This at leaft is true, if the veins are to
‘be accounted all of the fame formation; and,
in the greateft number of inftances by far,
ere is no mark of the one being pofterior to.
‘the other.
k 265. The induration of the fides of thefe
veins, in fome cafes, has been fuch, that the fides
have become more durable than the vein itfelf ;
Bie the whinftone has been worn away by
the wafhing of the waves, and has left the fides
ftanding up, with an empty fpace, like a ditch,
between them. One of thefe I remarked on the
fouth fide of Brodick Bay, in Arran, which,
where it met the face of an abrupt cliff, was not
kef than forty or fifty feet in depth.
266. I fhall pafs over whatever argument
fonia: be drawn in favour of our fyftem, from
the flender ramifications of the veins, and the
Varieties of their fizes, from a few inches to ma-
ny fathoms in diameter, and alfo from the con-
neđion which they often appear to have with the
p E tabular maffes of bafaltes; god fhall only
e add

HUTTONIAN:THEORT. goz

Biin, exhibit thefe veins in an varie-

in them were hardly fooner made than filled

302 . ILLUSTRATIONS OF THE

add a few remarks on the charring of coal ip
the vicinity of veins or maffes of whinftone,
The connection between the charring of coal
and the prefence ‘° whinftone, was firit obferved
by Dr Hutton; and, as far: as opportunities of
verifying the obfervation have yet occurred, ap-
pears to be a fa&@ no lefs general than it is cu-
rious and interefting. In the coal-mines of Scot-

land, it certainly holds remarkably, particularly

in thofe about Saltcoats in Ayrfhire, where a
whinftone dike is known to ftretch acrofs the
whole of the coal country, and to be every where
accompanied with blind or uninflammable coal.
At Newcaftle, dikes of the fame kind are met
with, and one, in particular, in: what is called
the Walker Colliery, has proved the action of
fubterraneous fire, to the fatisfa€tion of minera-
logifts nowife prejudiced in favour of the Hut-
tonian fyfiem, :

The coal found under bafaltes, in the Ifland
of Skye, has been already mentioned, § 139.
To what was faid concerning the fibrous ftruc-
ture of the parts of that foffil in immediate con-
taét with the whin, it may be added; that it is
alfo charred in thofe parts, fo as to have hardly
any flame when it is burnt, though further down
it is of the nature of ordinary coal. Indeed, if
there be any truth in Mr Kirwan’s general re-

mark,

— E

HUTTONIAN THEORY. — 303

SENS

4 ee it muft be underftood to arife from this,
quently charred, and its fibrous ftructure, by
‘that means, rendered. more ‘vifible.

3 267. It has been objected to the e
‘of coal having its bituminous part driven off
‘by the heat of the whinftone, that this ought
F; ot, on Dr Hutton’s principles, to happen in
he mineral regions. But it may be replied,
ihas been -done above, that the local ap-
ication of heat might certainly produce this

from a hotter to a colder. part of the fame
í ratum. The bitumen has not been fo vola-
tilized and expanded as entirely to efcape
fi rom the mineral regions; but it has been ex-
pelled from fome parts of a mafs, only to be
condenfed and concentrated in others. This
fp iron coincides exactly with the appear-
inces.

1 to two varieties. The firft is the moft common,
‘in which, though the coal is perfectly charred,
itis folid, and breaks with a fmooth and fhining
Tarface. The fecond is alfo perfect charcoal, but

very porousand fpungy.. This {ubftance is much
Tarer than the other: Dr Hutton mentions an

inftance

mark, that it is common to find wood:coal under

hat the coal in contact with the bafaltes is fre-

effet, and might drive off the volatile parts

268, The native or foffil-coke which accom- `
panies whinftone, has been diftinguifhed in-

304 ILLUSTRATIONS OF THE

inftance of it at the mouth of the river Ayr,
where there is a whinftone dike *. I had the
fatisfaction of vifiting it along with him. It
was in the bed of the river, below the high-wa.
ter mark ; the fpecimens had the exac& appear.
ance of a ‘Gina.

In the banks of the fame river, fome miles
higher up, he found a piece of coal, belonging
to a regular ftratum, involved in whinftone, and

extremely incombuftible. It confumed v

flowly in the fire, and deflagrated with nitre like
plumbago. This he confidered as the fame
foffil which has been defcribed under the name
of plombagine. Near it, and conne&ed with
the fame vein of whinftone, was a real and un-
doubted plumbago.

From thefe circumftances he alfo conclu-
ded, that plumbago is the extreme of a gra-
dation, of which foffil-coal is the beginning, and
is nothing elfe than this laft reduced to per-

fect charcoal. This agrees with the chemical —

analyfis, which fhows plumbago to be compofed
of carbon; combined with iron.

In confirmation of this theory, he men-
tions a fpecimen, in his poffeflion, of fteati-
tical whinftone, from Cumberland, containing
nodules of a very perfe&t and beautiful plum-
bago; and he alfo takes notice of a mine of this

pee

til

* Theory of the Earth, vol.i. p. 611.

HUTTONIAN THEORY. 305

Dr Kennedy, who has examined it with great
are, I can ftate as being contained, or enve-
bpi: in whinftone ; and I hope the public will
foon be favoured with a particular defcription
of this very interefting {pot, by the fame inge-
nious and accurate obferver.

4 269. Thus the mineralogical and chemical
di: overies agree in reprefenting coal, blind-coal,
plombagine, plumbago, as all modifications of
he fame fubftance, and as exhibiting the fame
p Ecin, carbon, in a ftate of greater or lefs

this feries fhould be placed the diamond ; but
we are yet unacquainted with the matrix of this
curious foffil, and its geological relation to other
m inerals. When known, they will probably
gi give t to this fubftance the fame place in the geo-
logical, as in the chemical arrangement : in the
mean time, it is hardly neceflary to remark,
how well all the preceding facts agree with the
hypothefis of the igneous formation of whin-
fone, and how anomalous and unconneéted they
a ae according to every other theory.

_ 270. Notwithftanding all this accumulated
and unanfwerable evidence for the i igneous for-
tion of bafaltes, a great objection would {till

s courate and eonelufive experiments toncern-
3 U ing

combination. As the laft and higheft term of-

Jatt, in Ayrfhire, which, on the authority of `,

re main to our theory, were it not for the very

306 ILLUSTRATIONS OF THE

ing the fufion of this foffil, referred to above,
$75. A ftrong prejudice againft the produc.
tion of any thing like a real ftone by means of
- fufion, had arifen, even among thofe mineralo-
gifts, who were every day witneffes of the ftony
appearance aflumed by volcanic lava. They
ftill maintained, on the authority of their own
imperfect experiments, that nothing but glafs

ean ever be obtained by the melting of earths or
of ftones, in whatever manner they are combi. —

ned.

block of bafaltes, in which he difcovered fuch

appearences, as inclined him to admit its igne-

ous confolidation, reje&s that hypothefis, mere-

ly from the imaginary inability of fire to give i
to any fubftance a ftony character: “ Quelque —

mélange,” fays he, “ de terres que Pon fuppofe,
quelque foit le degré de feu que Pon imagine,

quelque foit le tems que Pon emploie, il eft très `

certain que l’on n’obtiendra pas, par le feul fluide

igné, ni bafakte, ni rien qui lui reffemble *.”
Sir James Hall’s experiments have complete-

ly demonftrated the contrary of what is here

atferted ; they have added much to the evidence

of the Huttonian fyftem ; and, independently of

= Journal de Phyf, tom. xlix, (1799.) p. 36-

An ingenious naturalift, after defcribing a

all

a ee hee — a AAS

HUTTONIAN THEORY... 3

Í theory, have narrowed the circle of prejudice
4 pend error.

Note xv. § 83.
On Granite.

i Granite Veins. |

a It is faid above, § 77+, that gratiite ig
>f in unftratified maffes, and in veins. In the
rmer of thefe conditions, it conftitutes entire
mountains, and forms the central ridge of many
of the greateft chains that traverfe the furface
E the earth. It is the granite of this kind that |
has been moft generally defcribed by travellers —
and mineralogifts. The veins have not been
fo much attended to, though they are of pecu-
r importance for afcertaining the relation be-
n granite and other foflils.
292. Though Dr Hutton was the firft geologitt
who explained the nature of granite veins, and
who obferved with attention the phenomena
which accompany them, he is not the firft who
mentioned them. M. Beflon found veins
this kind in the Limoges, in an argillaceous ©
iftus, and unconnected, as far as appa, with
any aa mafs of granite *.
| 2 Sauflure

4 * Journal de Phyf. tom, xxix. p. 89.

308 ILLUSTRATIONS OF THE

Sauffure met with granite veins in the Valor-
fine, but did not fee them diftinaly. ‘He afcrib.
ed them to infiltration *. The date of this ob-
fervation is in 1776: He afterwards difcovered
fimilar appearances at Lyons +.

Werner alfo, in enumerating the fubftances
of which veins are formed, reckons granite as
one of them. |

273. Veins of granite may be confidered as of

two ine: according as they are conneéted, or

not connected apparently with any large mafs of
granite. It is probable, that thefe two kinds of
veins only differ in appearance, and that both

are connected with maffes of the fame rock,

though that connection is vifible in fome inftan-

ces, and invifible in others. The diftinétion, -

however, whatever it be with refpec& to the
thing obferved, is real with refpect to the ob-
ferver ; and, as it is right, in a defcription of

facts, to avoid every thing hypothetical, I thall

{peak of thefe veins feparately.

274. Veins of granite, having no communica-
tion, fo far as can be difcovered, with any mals of
the fame rock, are found in the Weftern If-
lands of Scotland, particularly in that of Coll,

where

* Voyages aux Alpes, tom. i, § 598, 599.
t+ Lbid. § 601,

HUTTONIAN — | 309

4 plend fchiftus, which compofe the main body
of the ifland. They are fometimes feveral
q fathoms n thicknefs, obliquely interfecting the
_ planes of the ftrata juft mentioned, which are
pearly vertical. In thefe veins the feltfpar is
_ predominant ; it is very highly cryftallized, and
of a beautiful flefh colour. Many {maller veins
y e alfo to be met with in the fame place; but
no large mafs of granite is found, either in this
or the adjacent ifland of Tiree.

= 275. The Portfoy granite, of which mention
4 has been already made, § 80, alfo conftitutes a
vein or dike, traverfing a highly indurated mica-
; ceous fchiftus, about a mile to the eaftward of
_ the little town of Portfoy, and not vifibly con-
nected with any large mafs of the fame kind.
- More dikes than one of this granite have been
- obferved ear the fame fpot. —

A fimilar granite is likewife found inland,
in the neighbourhood of Huntly, about eigh-
| teen miles fouth of Portfoy ; but whether in the |
ee of a vein or a mafs, I have not been able
to learn.

276. Veins of granite are alfo frequent in
q Reornivall, where they are known by the name
_ of lodes, the fame name which is applied in that
a country to metallic veins. The granite veins fre-
E U3 quently

310 ILLUSTRATIONS OF THE

quently interfe& the metallic, and are remarkable
for producing fhifts in them, or for throwing them
out of their natural direGion. The mineral Veins,
particularly thofe that yield copper and tin, run
nearly from eaft to weft, having the rote di-
rection with the beds of the rock itfel f, which
isa very hard {chiftus. The granite lodes, as
alfo thofe of porphyry, called elvan in Cornwall,
are at right angles nearly to the former ; and

it is remarked, that they generally heave the

mineral veins, but that the mineral veins fel.
dom or never heave the crofs- -yeins, In this
country, therefore, the veins of granite and pors

phyry are pofterior in formation to the metallic _

veins. ‘Thefe veins of granite may perhaps be
connected with the great granitic mafs that rung
longitudinally through Cornwall, from Dart-
moor tothe Land’s End. This much is certain,
that their dire@tions in general are fuch, that,
if produced, they would interfe@ that mals,
nearly at right angles.

277. The granite veins in Glentilt, where Dr
Hutton made his firft obfervations on this fub-
ject, are not, I believe, vifibly conne@ed with any
large mafs of the fame rock *. The bed of the ri-
ver Tilt, in the diftance of little more than a mile,

is

deem

* Trant. Royal Society Edin. vol, iii. p. 77, KC.

ae ee

Se a

ws

HUTTONIAN THEORY. 31I

y 4 js interfected by no lefs than fix very powerful
i, _ veins of granite, all of them accompanied with
| 7 fuch marks of diforder and confufion in the ftra-
| ta, as indicate very ftrongly the violence with
_ which the granite was here introduced into its
_ place. Thefe veins very probably belong to
the great mafs of granite which is known to
form the central ridge of the Grampians further
tothe north; but they are feveral miles diftant
- from it, and the connedtion is perhaps invifible
" in the prefent ftate of the earth’s furface.

_ 278. The fecond kind of granite vein, is one
d which proceeds vifibly from a mafs of that rock,

_ and penetrates into the contiguous ftrata. The
_ importance of this clafs of veins, for afcertain-
"T ing the relation between granite and other mi-
IU neral bodies, has been pointed out, § 82.; and
i by means of them it has been fhewn, that the
i) granite, though inferior in pofition, is of more
‘ recent formation than the fchiftus incumbent on
| it; and that the latter, inftead of having been
i} quietly depofited on the former, has been, long
after its depofition and confolidation, heaved up
j from its horizontal pofition, by the liquid body
-of granite forcibly impelled againft it from be-

low. |
la It has been alleged, in order to take off the
l force of the argument derived from granite
By D4 veins,

312 ILLUSTRATIONS OF THE

veins, that thefe veins are formed by infiltra-
tion, though, to give any probability to this
fuppofition, it would be neceflary to fhew, that
water is able to diffolve the ingredients of gra.
nite; and even if this could be done, the di-
rection which the veins have, in many inftances,
rifing up from the granite, is a proof, as remark-
ed § 82., that they cannot be the effed of in-
filtration. aa
` Another objedion has been thrown out, |
namely, that the veins here referred to are
not of true granite, according to the definition
which mineralogifts have given of that fubftance,
The force of a faa, however, is not to be leffen-
ed by a change of names, or the ufe of arbitrary

definitions. The general fad is, that the gra-

nitic mafs, and the vein proceeding from it, con-
ftitute one continuous, and uninterrupted body,
without any line of feparation between them,
The geological argument turns on this circum-
ftance alone; and it is no matter whether the
rock be a fyenite, a granitelle, or a real granite.
The phenomenon fpeaks the fame language, and
leads to the fame conclufion, whatever be the
technical terms the mineralogift employs in de-
{cribing it. i |

279. it muft, however, be admitted, that a
difference of character is often to be obferved
between the granite mafs and the veins proceed-

Ing

HUTTONIAN THEORY. 313

ing from it; fometimes the fubftances in thè
latter are more highly cryftallized than in the
F former; fometimes, but more rarely, they are
r ' lefs cryftallized, and, in fome inftances, an in-
7 gredient that enters into the mafs feems entirely
l wanting in the vein. Thefe varieties, for what
_ we yet know, are not fubje&t to any general rule ;
| but they have been held out as a proof, that the
q mafles and the veins are not of the fame forma-
tion, It may be anfwered, that a perfe& fimi-
larity between fubftances that, on every hypo-
- thelis, muft have cryftallized in very different
circumftances, is not always to be looked for;
"but the moft dire anfwer is, that this jaka
: -fimilarity does fometimes occur, infomuch that,
Mm in certain inftances, no difference whatfoever
ie ‘can be difcovered between the mafs and the
i, vein, but they confift of the fame ingredients, |
i] ‘and have the fame degree of cryftallization.
a _ Some inftances of this are juft about to be re-
i marked.
280. A ftrong objection to the fuppofed c ori-
gin of granitic veins from infiltration, and in-
- deed to their formation in any way but by ig-
if © neous fufion, arifes from the number of frag-
ments of fchiftus, often contained, and complete-
y infulated in thofe veins. How thefe frag-
“ments were introduced into the fiffures of the
" fehittus, and fuftained till they were furrounded ©

Eo

q . 7 ; -py

d
La

et

314 ILLUSTRATIONS OF THE

_ by the matter depofited by water, is very hard
to be conceived ; but if they were carried in
by the melted granite, nothing is more eafily
underftood.

The following are fome of the places where
the toads of granite veins may be difting.

ly feen.

= RN The ifland OE Arran, remarkable for col-
leCting into a very {mall compafs a great number

of the moft interefting facis of geology, exhibits
many inftances of the penetration of {chiftus by E

a EEEE E TENE x ett TAA m

veins of granite. A group of granite moun- —

tains occupies the northern extremity of the

ifland, the higheft of which, Goatfield, rifes

nearly to the height of 3000 feet, and on
the fouth fide is covered with {ehiftus to the
height of 1100. From thence, the line of junc-

tion, or that at which the granite emerges from —
under the fchiftus, winds, fo far as I was able |

to obferve, round the whole group of monntains,

with many wavings and irregularities, rifing
fometimes to a greater, and defcending fome- —
times to a much lower level, than that jut

mentioned. Along this line, particularly on
the fouth, wherever the rock is laid bare,

and cut into by the torrents, innumerable veins

of granite are to be feen entering into- the

sho growing narrower as they advance into —
; and being directed, in roy many cafes, from
below

B |_‘-HUTTONIAN THEORY. 315

T a

| below upwards, they are precifely of the kind
7 which the infiltration of water could not pro-
l 3 duce, even were that fluid capable of diffolving
T the fubftances which the vein confifts of. From
_ this fouth face of the mountain, and from the =
bed of a torrent that interfeds it very deeply,
Dr Hutton brought a block of {chiftus, of feve-
| yal hundredweight, curioufly penetrated by gra-
' nite veins, including in them many infulated —
agments of the ichiftus.

_ the granite and {chiftus defcends towards the
welt fide of the mountain, and is vifible at the
- bottom of a deep glen, (Glen- -Rofa), which de-
_ taches Goatfield from the hills farther to the —
d wef, The jundtion is laid bare at feveral pla-
ces in the bed of the river which runs in the
es; of this glen ; and in all of them exhi-
p bits in a greater or lefs degree, the appearan-
ces of difturbance and violence which have ac-
E vanied the injection of the granite veins.
a ial circumftances render this {pot interefting
toa geologift, and, among others, an interfec-
tion of the granite, a little above its jun@ion
"with the {chiftus, by a dike or vein of very com-
ad whinftone.
_ The fame line of jun@ion is found on the
_ Oppofite, or north-eaft, fide of the mountain,

an
a

where

4 From this, point, the common fe@ion ofo

316 ILLUSTRATIONS OF THE |

where it is interfe@ed by another little rive,
the Sannax, which on this fide determines the `
bafe of the mountain. This jun@tion i is no lef
remarkable than the other two.
The ifland of Arran contains, I have no
doubt, many other {pots where thefe phenome.
na are to be feen; but I have had no opportu-
nity of benii them, nor do I find that Dr _
Hutton met with any others in’ his vifit to o this
ifland. ug
= 282. Another feries of granite veins is faoal i
in Galloway, which was firt difcovered by Dr
Hutton and his friend Mr Clerk, and afterwards
more fully explored by Sir James Hall and
Mr Douglas, the`prefent Earl of Selkirk. The
two laft traced the line of feparation between
a mafs of granite and the fchiftus incumbent
upon it, all round a tra@ of country, about
eleven miles by feven, extending from the
banks of Loch Ken weftward ; and in all this
tract they found, “ that wherever the junction
of the granite with the fchiftus was vifible,
veins of the former, from fifty yards, to the
tenth of an inch in width, were to be feen
running into the latter, and pervading it in all
direCtions, fo as to put it beyond all doubt, that
the granite of thefe veins, and confequently of
the

HUTTONIAN THEORY. 31)

Ni the great body itfelf, which was obferved to
form with the veins one uninterrupted mafs,
muft have flowed ina See or liquid ftate into
E its prefent pofition*.”’ I have only further to
: 1 add, that forne of thefe veins are remarkable
for containing granite, not fenfibly different, in
any refpect, from the mafs from which they
_ proceed.

283. In Invernefsfhire, between Bernera and
i Fort Auguftus, the fame phenomena occur
a ‘on the north fide of Loch Chloney, where fomeé
i granite mountains rife from under the fchiftus.
In travelling near this place, Lord Webb Sey-
mour and myfelf were advertifed of our ap-
proach to a jundtion of granite and {chiftus,
le q by finding among the loofe ftones on the road
_ many pieces of {chiftus, interfeCted with veins
ji of feltfpar and granite. We walked along this
i _ junction for more than a mile; and toward
i the eat end, where the road leaves it, we faw,
p in the bed of a ftream that runs into Loch
S many beautiful fpecimens of granitic
J Veins pervading the fchiftus, and EA out
into very minute ramifications.

| 284. The laft inftance I have to men-
f tion from my own obfervation, is at St Mi-
f chael’s

i,

ae

. Tranf, Royal Society Edin, vol, iu. p. 8.

318. ILLUSTRATIONS OF THE

chael’s Mount in Cornwall. That mount js
_ entirely of granite, thruft up from under ag
_ very hard micaceous fchiftus, which furrounds
it on all fides. At the bafe of it, on the weft
fide, a great number of veins run off from the
granite, and fpread tħemfelves like fo many
roots fixed in the fchiftus : they are feen at low
water. In the fmaller veins, the granite is of
very minute, though diftin& parts; in the lars
‘ger, it is more highly cryftallized, and is undis ai
ftinguifhable from the mafs of the hill. S
Befides the above, Cornwall probably affords.
many other inftances of the fame kind, which I
have not had an opportunity to examine. Such
inflances may in particular be looked for at the
Land’s End, where a promontory, confifting of
_ a central part of granite, and covered by mica-
ceous fchiftus on both fides of it, is cut trank- |
verfely by the fea-coaft, and the conta@ of the
granite and {chiftus of courfe twice expofed to
view. i i
285- Scotland alfo affords other examples
of granite veins, and fome of them have been
actually defcribed. ` Mr Jamiefon has taken
notice of fome which he faw in the bottom
of the river Spey, at Glen Drummond, in
Badenach, and has reprefented them in an en-
graving.

HUTTONIAN THEORY. 319

Ering *. They traverfe the ftrata in va-
rious directions, and inclofe pieces of the mi-
caceous {chiftus; and, from the great number
of loofe blocks which he found, exhibiting por- |
tions of fuch veins, it is probable,. that they
are very numerous in this quarter. The fame
mineralogift mentions fome inftances of fimilar
veins in the Shetland Ifles $. "
n Rofs-fhire, Sir George Mackenzie has wee
fe ved a great variety of granite veins, fome of
them of large fize. One of them, in particular, ;
not far from Coul, when firft difcovered, was
4 fuppofed to be a fingle mafs, rifing from under
‘the {chiftus ; but, on a more careful examina-
tion, has been found to be a part of a great
fyftem of veins, which interfects the micaceous.
{ehiftus of this tract in various directions.
_ 286. The granite veins are not the only proof |
‘that this ftone is more recent than fome other
productions of the mineral kingdom. : Speci-
“mens of granite are often found, containing —
‘round nodules of other ftones, as, for example,
of gneifs ot micaceous f{chiftus. Such is the {pe-
cimen of granite containing gneifs, which Wer-
f ner himfelf is faid to be in poffeffion of, and
a s . -to

!

® * Mineralogy of the Scottith Hes, vol. ii, p. 173.
Lt Ibid. p. 216.

320 ILLUSTRATIONS OF THE

to confider as a proof, that the fchiftus is of
greater antiquity than the granite. Such alfo
feemed to me fome pieces of granite, which I
met with in Cornwall, near the Land’s End;
and others which I faw in Ayrfhire, in loofe
blocks, on the fea-coaft between Ayr and Gir-
van. It is impoflible to deny that the contain-
ing ftone is more modern than the contained,
The Neptunifts indeed admit this to be true,
but allege, that all granite is not of the ame ]
formation ; and that, though fome granite is re- q
cent, the greater part boafts of the higheft an:
tiquity which belongs to any thing in the fof- —
fil kingdom. This diftin@ion, however, is pure-
ly hypothetical; it is a fiction contrived on
purpofe to reconcile the fact here mentioned
with the general fyftem of aqueous depofition, ©
and has no fupport from any other phenome-
non.

2. Granite of Portfoy. i

287. The granite of Portfoy is one of the
moft fingular varieties of this ftone, and is re-
markable for this circumftance, that the felt-
fpar is the fubftance which has affumed the fi-
gure of its proper cryftal, and has given its form
to “@

HUTTONIAN THEORY. 32

y to the quartz, fo that the latter is imprefled both
“with the acute and obtufe angles belonging to
‘the rhombic figure of the former. The angu-
‘Jar pieces of quartz thus moulded on the felt-
“far, and ranged by means of it in rows, give
tothis ftone the appearance of rude Bees
“writing.
- Now, Dr Hutton argued, that fubftances pre-
J cipitated from a folution, and cryftallizing at
a cannot be fuppofed to imprefs one ano-
ther in the manner here exemplified; and that
they could do fo only when the whole mafs ac-
quired folidity at the fame time, or at the fame
time nearly *. Such fimultaneous confolidation
can be produced in no way that we know of,
but by the cooling of a mafs that has been in
| fufion. |
T 288. A granite, brought from Daouria by
) M. Patrin, and defcribed by him in the Journal
de Phyfique for 1791, p. 295, under the name of
pierre graphique, feemed to Dr Hutton to have
0 great a refemblance to the granite of Portfoy,
| iat he ventured to confider them both as the
| fame ftone, and as both containing quartz
T moulded on feltfpar t. It fhould feem, how-
T ever,
1 ;

| o Theory of the Earth, vol.i. p. 104.

t Tranf, Royal Society Edin, vol, iii. p. 83.

322 ILLUSTRATIONS OF THE

ever, from further explanations, which M. Pa.
trin has fince given, that Dr Hutton was mif
taken in his conjecture, and that, in the pierre
graphique of the former mineralogift, the quartz
gives its form to the feltfpar, preferving in its
cryftals their natural angle of 120 degrees *, Jt
is impoflible, I think, to doubt of the accuracy
of this ftatement; and the graphical ftone of `
Portfoy muft therefore be admitted to differ
materially from that of Daouria. They are not,
however, without fome confiderable affinity, be.
fides that of their outward appearance; for,
though the quartz in the former is generally
moulded on the felt{par, the feltfpar is alfo oc-
cafionally impreffed .by the quartz, and fome-
times even included in it. They may be con- —
fidered as varieties of the fame fpecies of gra- ”
nite; and the pierre graphique of Corfica is
probably a third variety, different from them
both.

289. It would feem, however, that all thefe
ftones lead exactly to the fame conclufion. M. Pa-
trin deferibes his fpecimen as containing quarts
cryftals, that are for the moft part only ca/es, hâ-
ving their interior filled with feltfpar. “ Le felt-
? fpath

* Journal Britannique (of Geneva), 1798, vol. vu.
Sciences et Arts, p. 78.

HUTTONIAN THEORY. 323

fpath en maffe contient des cryfteaux quartzeux,
= qui n’ont le plus fouvent que le carcafle, et dont
€ Yinterieur eft rempli de feltfpath; fouvent il
manque à ces carcaffes quelques unes de leurs

d faces, et fouvent la fection de cette pierre dans

un fens tranfverfal aux cryftaux, prefente une
d fuite de figures qui font ‘des portions d’hexagones,
T et qui ne refemblent pas mal à des carađtères
4 Hebraiques en

A Thefe imperfect hexagonal cafes of quartz,
l filled with feltfpar, certainly indicate the cry-

™ ftallization of fubftances, which all affumed
My _ their folidity at the fame time, and, in doing fo,
á 3 conftrained the figures of one another. To
y 7 ufe the words of Dr Hutton, “ whether cry-
La - flallizing quartz inclofe a body of feltfpar, or

" concreting feltfpar determine the fhape of fluid

II quartz, particularly if we have, as is here the

E cife, two folid bodies including and included, it

| amounts to a demonftration, that thofe bodies

i have concreted from a fluid ftate of fufion, and

A q have not cryftallized, in the manner of falts, from
gi 2 folution +.”

290. The quartz in granite fo generally re-
| tives the impreflions of all the other fubftances,
X 2 particularly

* Journal Britannique, :dd.

+ Tranf, Royal Society Edin. ubi /upra, p.84.

324 ILLUSTRATIONS OF THE

particulary of the felt{par and fchorl, and appears
to be fo paflive a body, that it has been doubted
by fome mineralogifts, whether in this ftone
it ever aflumes its own figure, except where
cavities afford room for its cryftallization. But
it is certain that, befide the Daourian granite
juft mentioned, there are others, in which the
quartz is completely cryftallized. Of this fort
are fome {pecimens, found in a granite vein on
the weft fide of the hill of St Agnes, in Corn-
wall. The vein traverfes the primitive fchif-
tus, of which that hill confifts, from fouth to
north nearly: the ftone is much decompofed,
and the feltfpar in general is almoft reduced
to the ftate of clay. In this decompofed mafs,
quartz cryftals are found, having the fhape of
double hexagonal pyramids, perfeCtly regular
and complete. The fide of the hexagon,
which is the bafe of the two oppofite pyra-
mids, varies from half a tenth to a tenth of an
inch in length, and is the fame with the altitude
of each of the pyramids. In fome few fpeci-
mens, the two pyramids do not reft on the fame
bafe, but are feparated by a very fhort, though
regular, hexagonal prifm. The furfaces of thefe
eryftals are rough, and fomewhat opaque, with
flender fpiculæ of fhorl frequently traverfing
them. This roughnefs is occafioned by flight

furrows

HUTTONIAN THEORY. 325

a furrows on the furface of the cryftal, very re-
| gularly difpofed, and parallel to one another,
being without doubt impreffions from the thin
| plates of the feltfpar, which furrounded the
| cryftal, and flightly indented it. They very

’ much refemble fome impreflions, remarked by
il Dr Hutton in the granite of Portfoy, and afcri-
W bed by him alfo to a fimilar caufe. He has re-

prefented thefe in his Theory of the Earth,
i) yol. i. plate 2. fig. 4. The aéion and reaction
tik)! of two cryftallizing bodies, hardly admits of a
ftronger and more unequivocal expreffion, than
» in thefe two inftances.

Where the granite was little decompofed,

the quartz was not eafily difengaged from the
sj) mafs it was imbedded in, and often broke in pie-

q ces before it could be extricated. The cryftalli-
a zation of the quartz, therefore, would not have
T been difcovered, but for the decompofition of
| the feltfpar; and it is probable, that fimilar
» cryftallizations exift in many granites where
| they are not perceived.

291. Some mineralogifts : are inclined to think,

* thatthe regular cryftallization of quartz is to be

found only in what they call fecondary granites,
or in thofe that are of a formation fubfequent to

_ the great maffes which conftitute the granite
© mountains. It is indeed true, that in the in-

A 3 {tances

326 ILLUSTRATIONS OF THE

ftances given here, both from Cornwall and
Daouria, the granites containing quartz-cryftals
are from veins that interfe& the primary {chif.
tus, and are therefore, on every hypothefis, of a
formation fubfequent to that fchiftus. But it
does not follow from thence, that they are lef
ancient than the great mafles of unftratified gra-
nite; with thefe laft they are moft probably
coëval, nor can there be any reafon for thinking
the cryftallization of quartz a mark of more
recent formation than that of feltfpar.

3. Stratification of Granite.

292. What are the various modes in which
granite exifts, is a queftion not abfolutely de-
cided among mineralogifts. r. That it exifts as
a {chiftofe ftone of a fiffile texture, in gneifs and
veined granite, is on all hands admitted, though
in this ftate the name of granite is generally
withheld from it. 2. That it exifts often with-
out any indication of a fiffile texture, and alto-
gether unftratified, is likewife acknowledged.
3. That it is found in veins, interfecting the
firata, has been fhown above. The only mode
of its exiftence fubject to difpute, is that in
which it is faid to be ftratified in its out-

= ward

oe

HUTTONIAN THEORY. 327

‘ward configuration, but not {chiftofe’ in its
texture. On this point mineralogifts do not
_ perfectly agree: Dr Hutton did not think that
this was a ftate in which granite ever appears,

When not fchiftofe in its ftructure, he fuppofed

“it to be unftratified altogether; and he con-
{dered it as a body which, like whinftone,
"was originally in a ftate of igneous fufion, and,

in that condition, injected among the ftra-
ta The fchool of Werner, on the other hand,

F maintain, that granite, if not always, is general-
ly firatified, and difpofed in beds, fometimes ho-
yizontal, though more frequently vertical, or
highly inclined.

In forming an opinion where there are great

' authorities on oppofite fides, a man muft truft
F chiefly to his own obfervations, and ought to
T efteem himfelf fortunate if thefe lead to any

certain conclufion. Mine incline me to differ
from Dr Hutton, on the one hand, and from
the Neptunifis on the other, as they convince
me, that granite does form ftrata where it has
no character of gneifs; and, at the fame time,
induce me to fufpect, that the ftratification

afcribed by the Neptunifts to the granite moun-

tains, is, in many inftances, either an illufion,
or at leaft fomething very different from what,
in other ftones, is accounted ftratification.

X 4 293. The

328 ILLUSTRATIONS OF THE

293. The firftexampleI ever faw of granite that
was ftratified, and yet had no character of gneifs,
was at Chorley Foreft, in Leicefterfhire. The
greater part of that foreft has for its bafe a horn-
ftone fchiftus, primary and vertical; and, on its
eaftern border, particularly near Mount Sorrel,
are beds-of granite, holding the fame diređtion
with thofe of the fchiftus. The ftone isa real.gra-
nite; it has nothing in its internal ftru@ture ofa
fchiftofe or fiffile appearance; and its beds, which
it is material to remark, are no thicker than thofe
of the hornftone ftrata in the neighbourhood,
This granite is remarkable too, for being clofe
to the fecondary fandftone {trata ; I did not fee
their contaé, but traced them within a {mall
diftance of one another ; fo that I think it is not
likely that any body of rock intervenes. At
the fame time that I flate my belief of this rock
of granite being in regular ftrata, I muft acknow-
ledge, that a very intelligent mineralogift, who
viewed thefe rocks at the fame time, and whofe
eye was well practifed in geological obfervation,
remained in doubt concerning them.

294. Another inftance of a real granite, difpo-
fed in regular beds, but without any character of
gneifs, is one which I faw in Berwickthire, in
Lammermuir, near the village of Prieftlaw. The
little river of Faffnet cuts the beds acrofs,

and

HUTTONIAN THEORY. 329

‘and renders it eafy to obferve their ftructure.
The beds are not very thick; they run from

about S. S. W. to N. N. E. like the fchiftus on

either fide of them. I was in company with —

| Sir James Hall when I faw thefe rocks; we ex-

i amined them with a good deal of attention, and
_ traced them for more than a mile in the bed of

the river; and, if I miake not, our opinions
concerning them were precifely the fame.
295. What exifts in two inflances may exiftin

many, and, after thefe obfervations, I fhould be

_ guilty of great inconfiftency, in refufing to affent

to the accounts of Pallas, De Luc, Sauffure, and
many other. mineralogifts, who fo often reprefent

_ granite as formed into ftrata. In fome cafes, how-
iil eyer, it is certain, that the ftratification they de-

fcribe is extremely unlike that in the two inftan-

_ ces juft mentioned, and indeed very unlike any
_ thing that is elfewhere known by the name of ftra-
í tification. For example, the ftratification muft
_ be very ambiguous, and very ob{curely marked,
__ that was not difcovered till after a feries of ob-

fervations, continued for more than twenty

‘years, by a very fkilful and diftinguifhing mi-

neralogift. Yet fuch undoubtedly is the ftra-

_ tification of Mont Blanc, and of’ the granite

mountains in its neighbourhood, as it efcaped

‘the eyes of Sauffure, in the repeated vifits

which he made to them, during a period of

no

330 ILLUSTRATIONS OF THE

no lefs extent than has juft been mention.
ed. It was not till near the conclufion of thofe
labours, to which the geologifts of every age
will confider themfelves as highly indebted,
that, having reached the fummit of Mont
Blanc, he perceived, or thought that he per-
ceived, the ftratification of the granite moun-
tains. The Aiguilles or Needles which border
the valley of Chamouni, and even Mont Blanc
itielf, appeared to be formed of vaft tabular
mafies of granite, in pofition nearly vertical, and
fo exactly parallel, that he did not hefitate to
call them by the name of ftrata. Till this mo-
ment, thefe fame mountains, viewed from a
lower point, had been regarded by him as com-
pofed of great plates of rock, nearly vertical
indeed, but applied, as it were, round an axis,
and refembling the leaves of an artichoke*;
and the fiffures by which they are feparated
from one another, had been confidered as effects
of wafte and degradation. “ But now,” (fays he,
{peaking of the view from the top of Mont
Blanc), “ I was fully convinced, that thefe
mountains are entirely compofed of vaft plates
of granite, perpendicular to the horrzon, and
directed from N. E. to S. W. Three of thefe
plates, feparated from each other, formed thẹ

top

* Voyages aux Alpes, tom. ii, § 910, &c.

HUTTONIAN THEORY. 331

i top of the diguille du Midi, and other fimilar
j plates, decreafing gradually in height, compofe
‘iy its declivity to the fouth *.”

296, Sauffure was fo ftrongly imprefled with the

j appearances of what he accounted regular ftra-
tification, fuch as water only can produce, and
7 fuch as muft have been in the beginning hori-
T zontal, that, placed as he now was, on one of
T the higheft points of the earth’s furface, he form-
F ed the bold conception, that the faummit on
which he was ftanding had been once bu-
T ried under the furface, to the depth at leaft of
half the diameter of the mountain, and horizon-
T tally diftant from its prefent place by a line not
4 lefs than the whole height of the mountain ; ;z-thg
{i granite beds which compofe that mountain,
having been raifed by fome enormous power
from their horizontal pofition, and turned as on
i an axis, till they were brought into the vertical
f plane. In this notion, which fuits fo well
with the nature of mountains really compofed
of vertical trata, and which does credit to
the extent of Sauffure’s views, it is wonder-

ful that he did not fee the overthrow of the

| geological fyftem he had adopted, which is pro-
_ vided with no means whatfoever of explaining
f thefe great effets.

Such,

* Voyages aux Alpes, tom. iv. § 1996.

332 ILLUSTRATIONS OF THE

Such, then, were the ideas fuggefted toSauffure,
by viewing the mountains of the Alps from the
higheft of their fummits. His great experience,
his accurate knowledge of the objects before
him, and the power he had acquired of difi-
pating thofe illufions, to which, in viewing
mountainous tracts, the eye is peculiarly fub-
ject, all confpire to give great weight to his
opinion. Yet, as this opinion is oppofed by
that which he himfelf had fo long entertained,
before it can be received with perfect confi-
dence, it will require to be verified by new ob-

fervations. It feems certain, that the beds of |

rock here defcribed, differ from all ordinary
ftrata, both horizontal and vertical, in the cir-
cumftance of their vaft thicknefs, three of them
being fo large as to form the main body of a
mountain. ‘Their parallelifm cannot eafily be
afcertained; and they have at beft but a very
flight refemblance to fuch beds as water is
known to produce.

297. Their parallelifm is difficult to be afcer-
tained ; for, on account of the magnitude and in-
- aceceffibility of the objects, it is impoflible to
place the eye in any fituation, where it fhall
not be much nearer to one part of the planes
whereof the parallelifm is to be eftimated, than
to another. Indeed, one can perceive a caule

which

HUTTONIAN THEORY. 333

: q which may have rendered the parallelifm of the
: ` 4 plates of granite which compofe the aiguilles,
| more accurate in appearance than in reality,
: _when viewed from a point fo elevated as the
iy _ fammit of Mont Blanc. For, even on the fup-
| pofition that the comparifon of thofe plates to
i, leaves of artichokes was juft, and that the planes
». of their feparation converged toward one ano-
"ther, in afcending to the top, when they were
` viewed from a point more elevated than that
top, this convergency would be diminithed, and,
| by the force of the perfpective, might even be
| converted into parallelifm. We cannot at pre-
OIT fent afcertain what effec this caufe of deception
n may have actually produced.
298. The obfervations of Sauffure concerning
WE the ftratification of granite, are not, however, in
tt all inftances, liable to thefe obje&tions ; and it
ti feems to be on much lefs exceptionable grounds
WE that he pronounces the granite of St Gothard to
4 fbe ftratified. The gneifs and micaceous fchiftus
W which conftitute the lower part of that mountain,
i are fucceeded bya granite without any {chiftofe
if j appearance, but divided into large plates, exa&ly
i! i parallel to the beds of the former gneifs. Thefe
if - he regards as real ftrata. On ftudying them in
A detail, he fays, confiderable irregularities were
j tobe obferved, but not greater than in the cafe
i of

334 ILLUSTRATIONS OF THE

of limeftone or micaceous {chiftus*. It may be
inferred from this, that thefe plates of granite
are not fo thick but that they admit of compa.
rifon with beds that are known with certainty
to be of aqueous formation, and I am therefore
difpofed to believe, that the granite of St Go.
thard, in this part at leaft, is ftratified. The tran.
fition from gneifs to granite en ma/fs, is not un.
common, as Sauffure has obferved in other in-
ftances, and as we are juft about to confider

more particularly. |
299. In the mountains of our own country, fome
difficulties concerning the ftratification of gra-
nite have alfo occurred. In Arran, for inftance,
the mountain of Goatfield, which I have men-
tioned above as affording an inftance of granite
fending out many veins into the ‘fchiftus, and
rivetted, as it were, by means of them to the
fuperincumbent rock, when I vifited it, with
a view of verifying on the fpot the interefting
obfervations which Dr Hutton had there made,
appeared to me to be without any vettige of ftra-
tification in its granitic part, as did alfo the
whole group of mountains to which it belongs.
It was, therefore, not without a good deal of fur-
prife, that I lately read, in an account of that
ifland, by a very accurate and ingenious mine-
ralogift,

# Voyages aux Alpes, tom. iv. § 1830.

HUTTONIAN THEORY. 335

ralogift, that Goatfield confifts of firatified gra-
nite*. The impreflion which the appear-

ance of that mountain made on my mind, is jut

the reverfe; and though I faw large tabu-
lar mafles, fometimes nearly vertical, feparated
by fiffures, they appeared to be much too irre-

gular, too little extended in length and height,
` and vaftly too much in thicknefs, to be reckon-

ed the effects of ftratification. For all this, I

~ would by no means be underftood to fet my ob-

fervations in oppofition to thofe of Mr Jamie-
fon, In my vifit to Arran, I did not dire& my

Mf inquiries much toward this point; the general

appearance of the rocks did not fuggeft the ne-

ich Thay ceffity of doing fo, and I was not perfectly aware

| q how much the firatification of granite had been
i) infited on by fome mineralogifts; fo that I
W applied myfelf entirely to ftudy fome other of
| the interefting phenomena which this little

wa iland offers in fo great abundance. I there-

' fore carry my confidence in the appearan-

ces which feemed to indicate a want of ftra-
tification in the granite of Arran no further
than to remain {ceptical both as to Mr Jamie-
fon’s conclufions and my own, till an oppor-

tunity

itt

_ * Mineralogy of the Scottifh Ifles, vol. i. p. 35, 36.

336 ILLUSTRATIONS OF THE

tunity fhall occur of verifying the one or the
other by actual obfervation.

300. The ftratification of granite, though it
made no part of Dr Hutton’s fyftem, does
by no means embarrafs his theory with any
new difficulty. Rocks, of which the parts
are highly cryftallized, are already admitted
as belonging to the ftrata, and are. exempli-
fied in marble, gneifs, and veined granite. In
the two laft, we have not only {tratification,
but a {chiftofe, united with a cryftallized ftruc.
ture, and the effects of depofition by water, and
of fluidity by fire, are certainly nowhere more

fingularly combined. The ftratification of thefe

fubftances is therefore more extraordinary than
even that of the moft highly cryftallized gra-
nite. Neither the one nor the other can be ex-
plained but by fuppofing, that while fuch a
degree of fluidity was produced by heat, as en-
abled the body when it cooled to cryttallize,
the whole mafs was kept in its place by great
preflure acting on all fides, fo that the fhape
was preferved as originally given to it by
the fea. As we cannot, however, fuppofe, that
the intenfity of the heat, or the fufibility of the
fubftance through all the parts of a ftratum, were
precifely the fame, we may expect to find in
the fame ftratum, or in the fame body of ftrata,
that in fome parts the marks of ftratification are

| completely

Ne È
tte iy
Mey
nf Ti
thy,
teady n
Sala
“INE ea
a Eed vi, y iri,
Sà tA cylin
tf dep *Pailtion by m
BE Certainly note
The ratificat
More extraordin
the mo highly ryti
the one nor the other at

y fsppoling, that while k
ay së produced by hei
= it cooled to j
gns kept in its pleh byi
gs e fo a i

f Hence a fudden tranfition from

ae eee

HUTTONIAN THEORY. 337

Ji
completely obliterated, while in others they re-
It is thus that veined granite, or
fhould be called granitic {chiftus,
gra-

main entire.
what I think
often graduates into granite in ma/s, that is,
nite without any {fchiftofe or fiffile texture.
Sauflure fays, that to be veined or not vein-
ed, is an affection of granite, that feems, in ma-
ny cafes, accidental *; as, in the midh of rocks
of that fubftance, moft clearly fiffile
d {tratifica-

, large por»
tions appear without any veftige
tion. Of this phenomenon, which is frequent
in the Alps, inftances are alfo to be met with
in the granite rocks of Scotland, and the adja-
cent ifles; and I know that Dr Hope, in a mi-

neralogical excurfion which he lately made
among the Hebrides, obierved many interefting
and curious examples of it. Indeed, when
rocks were fo much fufed as to cryftallize,
and fo comprefled, at the fame time, as to re-
they were evidently on the

two oppofite forces were very

main ftratified,

verge of change ;
nearly balanced, and each carried as far as it
could go without entirely overcoming the other ;
fo that a {mall alteration in the conditions may

have made a great alteration in the effects.

a ftratified to
an

a Voyages aux Alpes, tom. iv. § 2143.

338 ILLUSTRATIONS OF THE

an unftratified texture, which is only found jn
rocks highly cryftallized, and fuch as have en.
dured the moft violent a@tion of the minerali-

zing powers.
301. Now, though the ftratification of granite,
or the mixture of the ftratified with the unftra-
tified rocks of that genus, is not only reconcile.
able with the principles of the Huttonian geolo-
gy, but might even have been deduced as a corol.
lary from thofe principles, before it was aćtual-
ly obferved, it may be confidered as inconfiftent
with the theory of granitic veins that has juft
been given. A ftratum, though foft or fluid,
could not invade the furrounding ftrata with
violence, nor fend out veins to penetrate into
them. It might, if ftrongly compreffed by —
another ftratum lefs fluid than itfelf, fill up
any fiffures or cracks that were in that other,
but this would hardly produce fuch large
veins, and of fuch confiderable length, as often
penetrate from the granite into the fchiftus, —
nor could it give rife to any appearance of di- _
fturbance. If, therefore, veins were found pro-
ceeding from fuch ftratified granite as that of
Chorley Foreft or Lammermuir, I fhould think,
that the explanation of them was ftill a defide-
ratum in geology. The Neptunian theory of
infiltration would indeed be as applicable to
them

though fof yi

lutroundig tray

MRS out veins to pene
ght, if roagly comp
oe bets faid chan ikli
y cach that were in tht:
Jd hardly produce id i
ble length
s into the p

; 4 arate
pikwa pr di

eins were
spect 4 grant sb

HUTTONIAN THEORY. 339
them as to any other veins; for it is but little
affected by the condition of the phenomena to
be explained. Indeed, it is very difficult to fet
any limits to the explanations which this theory
affords ; and it would certainly puzzle a Neptu-
nit, to aflign any good reafon why infiltration
has not produced veins of one ichiftus running
into another, er veins of {chiftus running into
granite, as well as of granite running into {chif-
tus. He will find it a hard tafk to reftrain the
activity of his theory, and to confine its expla-
nations to thofe things that really exif.

302. As the Huttonian fyfiem cannot boaft of
theories of equal verfatility, it would be not a
little embarraffed to account for veins of great
magnitude proceeding from a rock diftin@ly
ftratified, and accompanied with marks of ha-
ving difturbed the rocks through which they pafs.
Lam, however, inclined to believe, that this em-
barraffment will never occur ; and that the grae
nite veins do not proceed from the rocks that are
really ftratified, but from fuch as have never been
depofited by water, and where the appearances of
{tratification, if there are any, are altogether il-
lufory. This anticipation, however, requires to be
verified by future obfervation ; and it remains to
be feen, whether granitic veins ever accompany
real granitic ftrata, or are peculiar to thofe in

Y2 which

340 ILLUSTRATIONS OF THE

which the appearances of regular beds are either
ambiguous, or are entirely wanting. The de.
cifion of this queftion is an object highly wor.
thy of the attention of geologitts.

303. An argument, directed at once againft the
igneous origin and unftratified nature of all gra.
nite, is given in a work already mentioned:
“ If granite had flowed from below, how does
it happen, that, after it had burft through the
ftrata of micaceous {chiftus, &c. it did not over-
flow the neighbouring country ? If this hypo-
thefis were true, Mont Blanc could never have
exifted *.”?

A theory is never more unfairly dealt with,
than when thofe parts are feparated which were
meant to fupport one another, and each left to
ftand or fall by itfelf. This, however, is pre-
cifely what is done in the prefent. inftance ; for
Dr Hutton’s theory of granite would not de-
ferve a moment’s confideration, if it were fo in-
artificially conftructed, as to fuppofe that gra-
„nite was originally fluid, and yet to point out
no means of hindering this fluid from diffufing
itfelf over the ftrata, and fettling in a horizon-
tal plane. The truth is, that his theory, at the
fame time that it conceives this ftone to have

been

dnan *

* Mineralogy of the Scettith Ifles, vol. ii, p. 166.

4

ee te

. |
= UD Wy

ADe could ay

A aent more unfairly dei
Oh parts are fence ii
Pet one another, and eu)
betel This, hover
done in the prelent infu
theory of granite woul i
g's ouabderatio0, if it we!
ss to foppot he

gly fo, snd yet OF
this 4yid fr 4
a

HUTTONIAN THEORY. 341
been in fufion, fuppofes it to have been, in that
ftate, injected among the ftrata already confo-
lidated ; to have heaved them up, and to have

een formed in the concavity fo produced, as in
a mould. Thus Mont Blanc, fuppofing that it
is unftratified, is underftood to confilt of a mafs
that was melted by fubterraneous heat under the
ftrata, and being impelled upwards by a force,
that may ftand in fome comparifon with that
which projected the planets in their orbits,
heaved up the ftrata by which it was covered,
and in which it remained included on all fides.

304. The covering of ftrata, thus raifed up,
may have been burft afunder at the. fummit,
where the curvature and elevation were, the
ereateit; but the melted mafs underneath may
have already acquired folidity, or may have
been fuftained by the beds of fchiftus incum-
bent on its fides. This fchiftus, forming the
exterior cruft, was immediately acted on by the
caufes of wafte and decompofition, which have
long fince ftripped the granite of a great part
of its covering, and aré now exercifing their
power on the central mafs. That even Mont
Blanc itfelf, as well as other unftratified moun-
tains, was once covered with fchiftus, will ap-
pear to have in it nothing incongruous, when
we confider the height to which the fchiftus ftill
rifes on its fides, or in the adjacent mountains ;

Y3 and

342 ILLUSTRATIONS OF THE

and when we refle&, that, from the appearances
of wafte and degradation which thefe moun-
tains exhibit, it is certain, that the fchiftus muĝ
have reached much higher than it does at pre-
fent.

It is obvious, therefore, that when the cor-
re{fponding parts are brought together, and pla-
ced in their natural order, no room is left for
the reproach, that this fyftem is inconfiftent
with the exi/fence of granite mountains. I have
no pleafure in controverfial writing ; and, not-
withftanding the advantages which a weak at-
tack always gives to a defender, I cannot but
‘regret, that Dr Hutton’s adverfaries have been
fo much more eager to refute than to under.
ftand his theory. 7

EE

305. A remark which Dr Hutton has made
on the quantity of granite that appears at the
furface, compared with that of other mineral
bodies, has been warmly contefted. Having
affirmed, that the greater part of rocks bear
marks of being formed from the wafte and de-
compofition of other rocks, he alleges that gra-
nite, (a ftone which does not contain fuch
marks), does not, for as much as appears from
actual obfervation, make up a tenth, nor perhaps

even

mie iga i

Caper to refute than y u

,,
<

$ which Dr Hutton bss

that app!
df ge Fhe

HUTTONIAN THEORY. 343

even a hundredth part of the mineral kingdom *.
Mr Kirwan contends, that’ this is a very erro-
neous eftimate, and that the quantity of granite
vifible on the furface, far exceeds what is here
fuppofed}. The queftion is certainly of no mate-
rial importance to the eftablifhment of Dr Hut-
ton’s theory : it is evident, too, that an eftimation,
which varies fo much as from a tenth toa hun-
dredth part, cannot have been meant as any thing
precile ; yet it may not be quite fuperfiuous to
fhow, that the truth probably lies nearer to the leaft
than the greateft of the limits juft mentioned.

306. Though granite forms a part, generally
the central part, of all the great chains of moun-
tains, it ufually occupies a much lefs extent of
furface than the primary fchiftus. Thus in the
Alps, ifa line be drawn from Geneva to Ivrea,
it will be about eighty-five geographical miles
in length, and will meafure the breadth of this
formidable chain of mountains, at the place of
its greateft elevation. Now, from the obferva-
tions of Sauffure, who croffed the Alps exactly
in this direction, it may be collected, that lefs
than nine miles of this line, or not above a
tenth part of it, in the immediate vicinity of
Mont Blanc, is occupied by granite.

Y 4 307% In

* Theory of the Earth, vol.i. p. 211.
t Geol, Effays, p. 480.

344 ILLUSTRATIONS OF THE

307. In fome fe&tions of the Alps, no granite”
at all appears. Thus, in the rout from Cham,
bery to Turin, acrofs Mont Cenis, which mea-
{ures by the road not lefs than ninety miles, no

granite is found, at leaft of that kind which i is
diftinally i in mats, and ‘different from gneifs or
veined granite *.

308. In fome other places of the fame moun-
tains, the granite is more abundant. A line
from the lake of Thun, along the courfe of the
Aar, and over the mountains to the upper end
of Lago Maggiore, croffes a very elevated trad,
and pafles by the fources of the Rhone, the
Rhine, and the Teffino, which laft runs into the
Po. A good deal of granite is difcovered here,
in the mountains of Grimfel and St Gothard ; |
but by far the greater part of it is the va 7
granite, the granite in mafs being confined
chiefly to the north fide of the Grimfel. Both
together do not occupy more than one-third of
the line, and therefore the fatter lefs than one-
fixth.

309. The effay on the ae of the Py-
rences, by the Abbé Patasso, contains a mine-
ralogical chart of thofe mountains. From this
chart I have found, by computation, that the
granite does not occupy one- fifth of the hori-
zontal

* Voyages aux Alpes, tom, iii. § 1190, Ke.

t cal |
Me i Sof the lana
í Tha, nm Mund
Re ti
4 to the Ute

PS A VETY eleva,
' the PAIS of the i
tT Which lat ri
dea. of granite is difton
a of Grime! and SG

Pee part of it is tke
pant in mais being ct
woth Gide of the Grin }
g oop Dore than onet
gime the latter lels tw

ai spineralog! j

HUTTONIAN THEORY.

FAE
JF)

zontal furface on the north fide of the ridge,

In-
deed, many great tracts, even of the central

reckoning from one end of it to the other.

tain no granite what-
the higheft mountains

A large
deduction fhould be made from the fra¢tion +,

parts of the Pyrenees, con
foever ; and not a few of
confift entirely of calcareous {chiftus.

on account of the fubftances unknown, which,
from the conftruction of the chart, are often
confounded with the granitic trad.

310. I might add other eftimations of the
fame kind, all confeffedly rude and imper-
fe&, but ftill conveying, by means of num-
bers, a better idea of the limit to which our
knowledge approximates, than could be done
fimply by words; and, on.the whole, it would
appear, that if we ftate the proportion of gra-
nite to {chiftus to be that of one to four, we
fhall certainly do no injuftice to the extent of
the former. 3

It remains to form a rough eftimate from
maps, and from the accounts of travellers, of
what proportion of the earth’s furface confifts of
primary, and what of fecondary rocks. After
fupplying the want of accurate meafurement by
what appeared to me the moh probable fuppo-
fitions, I have found, that about —, of the fur-
face of the old continent may be conceived to
be occupied by primitive mountains; of which,

if

$
346 ILLUSTRATIONS OF THE

if we take one-fifth, we have 35 for the part
of the furface occupied by granite rocks, which
differs not greatly from the leaft of the two li-
mits afligned by Dr Hutton.

311. In eftimating the granite of Scotland,
Dr Hutton has certainly erred confiderably in
defect *, and Mr Kirwan, who always: differs
from him, is here neareft the truth ; though he
is right purely by accident, as the information
on which he proceeds is vague and erroneous,

The places in Scotland where granite is
found, are very well known; but the extent
of fome of the moft confiderable of them is
not accurately afcertained. In the fouthern
parts, except the granite of Galloway, which
is found in two pretty large infulated tracts,
there is no other of any magnitude. The gra-
nite of the north extends over a large di-
ftri&. If we fuppofe a line to be drawn, from
afew miles fouth of Aberdeen to a few miles

| fouth

* Dr Hutton in this cafe no doubt made a very loofe
eftimate. He fays, the granite does not perhaps occupy
more than a 5ocdth part of the whole furface. The
whole furface of Scotland is not much more than 23,000
geographical miles, the seodth part of which is exactly
46; and this is exceeded by the granite in Kirkeud-
brightfhire alone, as may be gathered from what iş
faid § 202.

ey wel known: byt b |

a di
Be wel condendi q i
By akertained. In ih k
Ete granite of Galowy,
imo pretty large inl
ther of any magnitude. T
worth extends over 3
| scope » line to be de

sath of Aberdeen 1

"ag
GA
ee |

yp! .
|

HUTTONIAN THEORY. 347
fouth of Fort-William, it will mark out the cen-
tral chain of the Grampians in its full extent,
pafling over the moft elevated ground, and by

F the heads of the largeft rivers, in Scotland.

Along this line there are many granite moun-

,. tains, and large tracts in which granite is the

prevailing rock. ‘There are, however, large
{paces alfo in which no granite appears, though,
if we were permitted to fpeak theoretically,
and if the queftion did not entirely relate to
a matter of obfervation, we might fuppofe,
that, in no part of this central ridge is the gra-
nite far from the furface, notwithftanding that
in fome places it may be covered by the fchif-
us.

312. A great part of the Grampian mountains
is on the fouth fide of the line juft mentioned, but
hardly any granite is found in this divifion of
them, except fuch veins as thofe of Glentilt.
On the north fide of the line, the granite extends
in various directions; and, if from Fort-Wil-
liam a line is drawn to Invernefs, the quadri-
lateral figure, bounded on two fides by thefe
lines, and on the other two by the fea, will be
found to contain much granite, and many di-
ftris confifting entirely of that ftone. This is
in faét the great granite country of Scotland:
it is a large tra, containing about 3170
{quare geographical miles, or about a feventh

part

et

348 ILLUSTRATIONS OF THE

part of the whole : but the proportion of it occy.
pied by granite cannot at prefent be afcertained
with any exactnefs, nor will, till fome minera.
logift fhall find leifure to examine the courfes
of the great rivers, the Dee, the Spey, &c. which
traverfe this country. If we call it one-fourth
of the whole furface, its extent is certainly not
under-rated, and will amount to 790 {quare miles
nearly ; to which adding 150, as a very full al-
lowance for all the other granite contained in |
Scotland, exclufive of the ifles, we fthall have
940 fquare miles, between a twenty-fourth and
twenty-fifth part of the furface of the whole,

This computation, it muft be obferved, aims
at nothing precife, but I think it.is fuch, that a
more accurate furvey would rather diminith than
increafe the proportion ailigned in it to the gra-
nite rock.

313. This refult may perhaps fall as much

fhort of Mr Kirwan’s notion, as it exceeds the —

eftimate made by Dr Hutton. If it fhall not, and
if the former has, in this inftance, come neareft
the truth, it cannot be afcribed to the accuracy
of his information, or the foundnefs of the prin-
ciples which directed his refearch. Mr Wir-
L1AMS, whom he quotes, was a miner, of great
fkill and experience in fome branches of his
profeflion, to which, if he had confined him-
felf, he might have written a book full of ufe-

3 | ful

the € ille es, |
We a
Wer A| at =
' 4 twenty- ~ion
‘ uTiace o Ot Ethe nhi

S Dat d think itis fhi

|

ey would rather dim

00 ail Tenet init tote
g tot

+ may pernp filla!

a
=s °

de Hot! ffon. If ith

okt fa Na on
di

Í jo A

p

S
4 Eiei

> R
mnf
> A Mit de oben

n tion, as 1 a

HUTTONIAN THEORY. 349

ful information. What he fays on the fubje&
of granite, is, in the main I believe juft ; but
it is far too general to author rife the conclufion
which Mr Kirwan derives fromit. Dr Asun, for
whofe judgment I have great refpect, cannot,
I think, have meant, when he ufed the expref-
fion granitic rocks, at
fo called. He fays,
Mr Kirwan, that
and Berwick, there is a

to defcribe granite ftridily
in the paffage quoted by
‘‘ from Gallow ay, Dumfries,

chain or Moul tains Dy

Now, the fact is, that the great belt ¢
rock, here alluded to,
of Scotland,

rious kinds ; but except in Galloway, and again

commonly ee eee but often alfo granitic.”
of primary

which traverfes the fouth

confifts of vertical {chiftus of va-

in Lammermuir, near Prieftlaw, it appears, as
already mentioned, to contain no granite what-
foever. If the German mineralogift quoted by
Mr Kirwan, when he fays that the Grampian
mountains confift of mica

ceous limeftone, gneuls,

D Se ee e $ ith
; and granite, aiternating wit

e^

porphyry, argillite
one another, means only to affirm that all t
ftones are found in the Grampians, he is certain-
ly in the right, and the catalogue might eafily be
enlarged ; but, if
thefe are nearly in equal abundance, or that the
granite is abies found in ftrata alternating
with other {

he either means to fay

trata, I muf fay, that thefe are pro-

ILLUSTRATIONS OF THE

pofitions quite contrary to any thing I have evet
feen or heard of thofe mountains. -But it is pro-
bable that this is not meant, and that the fault
lies in underftanding the expreffions much
too literally. Mr Kirwan accufes Dr Hutton
of not knowing where to look for the granite;
not aware of how much, notwithftanding any
error committed in the prefent eftimate, he
was {killed in the art of mineralogical obfer-
vation ; an art, which thofe who have not prac-
tifed do not always know how to appreciate,
But, however imperfe& Mr Kirwan’s know-
ledge of this fubjeét has been, he has here had
the good fortune to correct a mineralogift of
very fuperior information. The mete difpofi-
tion to oppofe is not always without its ufe:
no man i$ in every thing free from error, and,
to controvert indifcriminately all the opinions
of any individual, is an infallible fecret for being
fometimes in the right.

Nore xvi. § 100.

Rivers and Lakes.

314. Rivers are the caufes of wafte moft vi-
fible to us, and moft obvioufly capable of
producing

HUTTONIAN THEORY. 331

n | producing great effets. It is not, however, in

the greateft rivers, that the power to change
and wear the furface of the land is moft clearly

Y Ry q feen. It is at the heads of rivers, and in the
» % feeders of the larger ftreams, where they defcend

over the moft rapid flope, and are moft fubje&
to irregular or temporary increafe and diminu-
tion, that the caufes which tend to preferve, and
thofe that tend to change the form of the earth’s

My furface, are fartheft from balancing one another,

i and where, after every feafon, almoft after eve-
Ty flood, we perceive fome change produced,

Wk) for which no compenfation can be made, and

_fomething removed which is never to be replaced.
When we trace up rivers and their branches
toward their fource, we come at laft to rivulets,
that run only in time of rain, and that are dry
at other feafons. It is there, fays Dr Hutton,
that I would wifh to carry my reader, that he
may be convinced, by his own obfervation, of
this great fa, that the rivers have, in general,
hollowed out their valleys. The changes of the
valley of the main river are but flow; the plain
indeed is wafted in one place, but is repaired in
another, and we do not perceive the place from
whence the repairing matter has proceeded.
That which the fpe@ator fees here, does not
| therefore immediately fuggeft to him what has
A been the ftate of things before the valley was
j hollowed

$52 ILLUSTRATIONS OF THE

hollowed out. But it is otherwife in the valley

of the rivulet; no perfon can examine it with.
out feeing, that the rivulet carries away matter
which cannot be repaired, except by wearing
away fome part of the furface of the place upon
_which the rain that forms the ftream is gathered,
The remains of a former ftate are here vifible;
and we can, without any long chain of reafon-
ing, compare what has been with what is at the
prefent moment. It requires but little fludy to
replace the parts removed, and to fee nature at
work, refolving the moft hard and folid maffes,
by the continued influences of the fun and at-
mof{phere *. We fee the beginning of that long
journey, by which heavy bodies travel from the
fummit of the land to the bottom of the ocean,
and we remain convinced, that, on our continents,
there is no {pot on which a river may not formerly
have run +.

315. The view thus afforded of the ope-
rations, in their nafcent ftate, which have fha-
ped out and fafhioned the prefent furface of
the land, is neceflary to prepare us for fol-
lowing them to the utmoft ‘extent of their
effets. From thefe effects, the truth of the
propofition, that rivers have cut and formed, not

the

aa oneal

* Theory of the Earth, vol. ii. p. 294,

N eS

ard and fil t
wdoences of the fan

ae the bezinning oi

j Beary bodies travel ty
id to the bottom of te
fumced, that, on our cue
thich a river may nijn

ibas afforded of
feat fate,
ped e P

yy t9 prepar

{
i

f
n

refent M

)
W
g

TH

7 hich bait

i to the Danube.

HUTTONIAN THEORY. 353
the beds only, but the whole of the valleys, or
rather fyftem of valleys, through which they
flow, is demonftrated on a principle which has
a clofe affinity to tl

ufually calculated, § go.
tightly the courfe of a great river, and the com-
munication fubfifting between the main trunk
and its remoteft branches, let us take the in-
tance of the Danube, and cat our eyes on
one of the maps conftructed by Marsicut, fox
illuftrating the natural hiftory of that great ri-
ver*, When it is confidered, that over all the
valt and uneven furface, which reaches from the
Alps to the Euxine, and from the mountains of
Crapack to thofe of Hæmus, a regular commu-

at on which chances are

In order to’ conceive

nication is kept up between every point and

the line of greateft depreffion, in which the ri-
ver flows, no one can hefitate to acknowledge,

“that it is the agency of the waters alone which

has opened them a free paflage through all the
intricacies of this amazing labyrinth. In effeĝ,
fuppofe this communication to be interrupted,

“fand that fome fudden operation of nature were
to erect a barrier of mountains to oppofe the

Theife or the Drave, as they rolled their waters
From this what could poflibly
refult, but the damming up of thofe rivers till

L their

ie

* Hiftoire du Danube, tom. i. tab. 34.

354 ILLUSTRATIONS OF THE

their waters were deep, or high enough to find
a vent, either under the bafes or over the tops of
the oppofing ridge. ‘Thus there would be form.
ed immenfe lakes and immenfe cataracts, which,
by filling up what was too low, and cutting
down what was too high, would in time reftore
fuch a uniform declivity of furface as had before
prevailed. Juft fo in the times that are paft,
whatever may have been the irregularities of the
furface at its firt emerging from the fea, or
whatever irregularities may have been produced

in it by fubfequent convulfions, the flow ac-

tion of the ftreams would not fail in time to
create or renew a fyftem of valleys commu-
nicating with one another, like that which we
at prefent behold. Water, in all circumftan-
ces, would find its way to the loweft point;
though, where the furface was quite irregu-

lar, it would not do fo till after being dammed _

up in a thoufand lakes, or dafhed in cataracts
over a thoufand precipices. Where neither of
thefe is the cafe ; and where the lake and the ca-
taract are comparatively rare phenomena ; there
we perceive that conftitution of a furface, which
water alone, of all phyfical agents, has a tenden-
cy to produce; and we muft conclude, that the
probability of fuch a conftitution having. arifen
from another caufe, is, to the probability of its

having

se

ee ee ee E ENE

E oa a

a ee ee a ee

oe ae Oe

HUTTONIAN THEORY. 555

having arifen from the running of water, in fuch

E, proportion as unity bears to a number infinite-

E dy great.
_ 316. The courfes of many rivers retain marks

_™ that they once confifted of a feries of lakes,
W which have been converted into dry ground, by

‘the twofold operation of filling up the bottoms,
" and deepening the outlets. This happens, efpe-

by cially, when fucceffive terraces of gravelly and
di Aat land are found on the banks of a river, § 100.

q Such platforms, or haughs as they are called in

i i this country, are always proofs of the wafte and
li t 1 detritus produced by the river, and of the dif-

but they

wh J fometimes lead us farther, and ake it cer-
alc tain, that the great mafs of grav el which forms

the fucceflive terraces on each fide of the ri-

me | ver, was depofited in the bafon of a lake. If,

“from the level of the higheft terrace, down

ssf to the prefent bed of the river, all is alluvial,

and formed of fand and gravel, it is then evi-
dent, that the {pace as low as the river now runs
l muĝ have been once occupied by water; at the
i fame time, it is clear, that water muft have ftood,

i ; or flowed as high at leaft, as the uppermoft fur-

7 face of the meadow. Itis impoflible to recon-

L j cile thefe two facts, which are both undeniable,

: | but by fuppofing a lake, or body of ftagnant wa-
E ter, to have here occupied a great hollow,

AF 3 (which by us muft be held as one of the origi-

2 nal

336. ILLUSTRATIONS OF THE

nal inequalities of the globe, becaufe we can
trace it no farther back), and that this hollow,
in the courfe of ages, has been filled up by the
gravel and alluvial earth brought down by the
river, which is now cutting its channel through
materials of its own depofiting. There is no
great river that does not afford inftances of this,
both in the hilly part of its. courfe, and where
it defcends firft from thence into the plain.
Were there room here for the minuter details
of topographical defcription, this might be il-
luftrated by innumerable examples.

317. It is faid above, that the water muft
have run or ftood, in former times, as low as the
prefent bottom of the river; but there ts often
clear evidence, that it has run or ftood much
lower, becaufe the alluvial land reaches far be-
low the prefent level of the river. This is known
to hold in very many inftances, where it has
happened that pits have been funk to confider-
able depths on the banks of large rivers. By
that means, the depth of the alluvial ground,
under the prefent bed of the river, has been dif-
covered to be great; and from this arifes the
difficulty, fo generally experienced, of finding
good foundations for bridges that are built ovet
rivers in large vallies, or open plain, the ground
being compofed of travelled materials to an un-
known depth, without any thing like the native

or

HUTTONIAN THEORY. 357

or {olid flrata. In fuch cafes, it is evident, that

| q formerly the water muft have been much low-

er, as well as much higher, than its prefent level,
and this is only confiftent with the notion, that

Í the place was once occupied by a deep lake.

= 318. If, following the light derived from thefe
- indications, we go back to the time when the
"river ran above the higheft of thofe levels at
` which it has left any traces of its operations, we
fhall fee it compofed of a feries of lakes and ca-

1 taracts, from which, by the filling up of the one,

_ and the wearing down of the other, the waters

j have at length worked out to themfelves a quiet

, and uninterrupted paffage to the ocean. We
wl may, indeed, on good evidence, go back fill
wi farther than the fucceffion of fuch meadows or
ii} terraces, as are above mentioned, will carry us,

and may confider the whole valley, or trough of

iti), the river, as produced by its own operations.

_ The original inequalities of the furface, and the

: m - difpofition of the ftrata, muft no doubt have de-

termined the water-courfes at firt; but this
does not hinder us from confidering the rivers as

i 4 l having modified and changed thofe inequalities,

and as the proximate caufes of the fhape and con-
_ figuration which the furface has now affumed.
319. From this gradual change of lakes into

# Tivers, it follows, that a lake is but a temporary

= and accidental condition of a river, which is
L 3 every

359 ILLUSTRATIONS OF THE

-every day approaching to its termination; and
the truth of this is attefted, not only by the lakes
that have exited, but alfo by thofe that conti:
nue to exiit. “Where any confiderable ftream
enters a lake, a flat meadow is ufually obferved
increafing from year to year. The foil of this
meadow is difpofed in horizontal ftrata: the
meadow is terminated by a marth ; which marth
is acquiring folidity, and is foon to be converted
into a meadow, as the meadow will be into an
arable field. All this while the fediment of the
river makes its way flowly into the lake, forming
a mound or bank under the furface of the wa-
ter, with a pretty rapid flope toward the lake. .
This mound increafes by the addition of new
earth, fand, and gravel, poured in over the flope;
and thus the progrefs of filling up continually
advances. )

320. In {mall lakes, this progrefs may eafily be
traced ; and will be found fingularly confpicuous
in that beautiful affemblage of lakes, which fo
highly adorns the mountain fcenery of Weft-
moreland and Cumberland. Among thefe a
great number of inftances appear, in which lakes
are either partially filled up, or have entirely
difappeared. In the Lake of Kefwick, we not
only difcover the marks of filling up at the up-
per end, which extend far into Borrowdale, from
which valley a {mall river flows into the lake ; but
we have the cleareft proof, that this lake was once

united

i lar ; Be

¥ is Inn, 4

R | M to be COs
i -wk lii
T the fedir ma
M bow! I mt

to Maly els ake fp

= rhace of I Ii

nmi ne toward th,
taies Oy the addition

BPC, poured in overt

peas Of nuog up cont

res. | this prog pe of th

n .
phani ue

m it

HUTTONIAN THEORY. 359

united to that of Baffenthwa'te, and occupied
the whole valley from Borrowdale to Oufe-
Bridge. Thefe two lakes are at prefent joined
only by a ftream, which runs from the former
into the latter, and their continuity is inter-
rupted by a confiderable piece of alluvial land,
compofed of beds of earth and gravel, without
rock, or any appearance of the native ftrata.
This feparation, herefore, feems no other than
a bar, formed by the influx of two

rivers,

that enter the valley here from oppofite fides,

the Greata from the eaft, and Newland’s Wa-
from the weft. ‘The furface of this mea-
dow is at prefent twelve or fifteen feet at leaft
above the level of either lake ; and a quantity of
water of that depth muft therefore have been
drawn off by the deepening of the iffue at
Oufe-Bridge, through which the water of both
lakes paffes, in its way to the ocean.
Many more examples, fimilar to this, may be
collected from the fame are In-
deed few places from which, in

lakes 3 there
this branch of
geology, more information may be collected.
321. The larger lakes e: se ogee the fame pro-
erefs. Where the Rhone enters the Lake of Ge-
neva, the beach has been obferved to receive an
annual increafe; andthe Portus Valefiz, now Pre-
vallais, which is at pretent half a league from the
lake, was formerly clofe upon its bank. Indeed,
the fediments of the Rhone uppear clearly to

Z A. have

è

g60 . ILLUSTRATIONS OF THE

have formed the valley through which it runs,

to a diftance of about three leagues at leaft from
the place where the river now difcharges itfelf
into the lake, The ground there is perfectly ho.
rizontal, compofed of fand and mud, little raifed
above the level of the river, and full of marfhes,
The depofition made by the Rhone after it en-
ters the lake, is vifible to the eye; and may be
feen falling down in clouds to the bottom.

The great lakes of North America ate under-
going the fame changes, and, it would feem, even
with more rapidity. As the rivers, however,
which fupply thefe vaft refervoirs, are none of
them very great, the filling up is much lefs re-
markable than the draining off of the water, by the
deepening of the outlet. An intelligent travel-
ler has remarked, that in Lake Superior itfelf
the diminution of the waters is apparent, and
that marks can be difcovered on the rocks, of the
furface having been fix feet higher than it is at
prefent. In the fmaller lakes this diminution is
fill more evident *. In fome of thofe far inland,
the ground all round ea gaps to the fame tra-
wie to be the depofite from the rivers, of which
the lakes ea Aes may be confidered as
mere expanfion +.

et
pasadi

322. Tn

* Mackenzie’s Voyages through the Continent. of

North America to the Frozen and Pacific Oceans,
pe xlii, and xxxvi. t lb:d. p. 122.

A

> Ming up 1S much

hers
raur uz BU {
pi

fof the Water, i
Kiet. An intelligent m

oh ub Lidl

ikat in Lake Superi

be Waters 15 appari:
0 prened on the rock

ix i bet higher th nit

ler | this sa
ame gi we
pct tot we

7 t 1c rivers, a”
p” ‘ La confit’
py”

tf

cataracts are entirely obliterated ;

rT Tr AT TINE TISLAYQY XF ria
À Bia e Y ahr
HU LT T ON TI AD Ae H AG, Nie 20 s

322. In order to uniform

the rivers, the lakes

r Jay ritip :
give ceciivities to
7

muft not only be filled up or

y

k ~ 3 S & S d ye $ A 3 A
drained, but the cataract, wherever there is one,

t,
The latter is an operation
The ftream, as it precipi-
tates itfelf over the rocks, hurries along with it,
not only fand and gravel, but occafionally large
ftones, which grind and wear down the rock
with a force proportioned to their magnitude
and acceleration. The fmooth furface of the
waterfalls, their rounded furface,
and curious excavations, are the moft fatisfac-
tory proofs of the conftant attrition which they
endure; and, where the

muft be worn away.
in all cafes vifible.

rocks in all

rocks are deeply in-
terfeted, thefe marks often reach to a great
height above tl on which the water now
flows. The phenomena, in fuch inftances, are

am ong

1e level

the arguments beft calculated to remove
all redali ty refpećđting the wafte which ri-
vers have produced, and
produce. They fuffer no doubt to remain,
that the height and afperity of every waterfall
are continually diminifhing ; that innumerable
that thofe
which remain are verging toward the fame end,
and me the Falls of Montmorenci and Niagara
muft ultimately difappear
523. Eck thane can be no doubt of the juft-
nefs of the precedin

or
wAAA LS
oO

are continuing to

conciuiions,

when ay pplied
to

362 ILLUSTRATIONS OF THE

to lakes in general, fome apparent exceptions
occur, in which the progrefs of draining and
filling up feems to have been fufpended, or even
to have gone in a contrary direction. Thete
exceptions confift of the lakes which appear to
have received a greater quantity of materials
than was fufficient to have filled them up. Such,
for example, is the Lake of Geneva, which re-
ceives the Rhone defcending from the Vallais,
one of the deepeft and longeft vallies on the fur-
face of the earth. Now, if this valley, or even
a large proportion of it, had been excavated by
the Rhone itfelf, as our theory leads us to fup-
pofe, the lake ought to have been entirely fill-
ed up, becaufe the materials brought down by
the river feem to be much greater than the lake,
on any reafonable fuppofition concerning its ori-
ginal magnitude, can poflibly have received.
What, then, it may be faid, has become of all
that the Rhone has brought down and depofit-
ed in it? The lake, at this moment retains,
in fome places, the depth of more than 1000
feet; and yet, of all that the Rhone carries in-
to it, nothing but the pure water iflues. Ks
it has been continuing to diminifh, both in
fuperficial extent and in depth, from the time
when the Rhone began to run into it, what mut
have been its original dimenfions °.

[

HUTTONIAN THEORY. 363

I cannot pretend to remove entirely the dif-
culty which is here ftated; yet I think the
following remarks may go fome length in doing
fo.

324. It is certain, that from the prefent ftate
of the lake of Geneva, and of the ground
round it, we can hardly draw any inference
as to its original dimenfions. Sauflure has
traced, with his ufual fkill, the marks of the
courfe of the Rhone, on a level greatly above
the prefent ; and, by obfervations on the fide of
Mount Saleve, has found proofs of the running
of water, at leaft 200 toifes above the prefent
fuperficies of the lake. But, if ever the fuper-
ficies of the lake ftood at this height, or at this
height nearly, though we can conjecture but

™ little concerning the ftate of the adjacent coun-
™ try, which no doubt was alfo on a higher level,

the lake may very well be fuppofed to have been

pwn ate of far greater dimenfions than it is now. It may

have occupied the whole fpace from Jura to Sa-
leve, and included the Lake of Neufchatel; fo
that it may have been of magnitude fufficient
to receive the {poils of the Valais, which, as the

f furface of its waters lowered, may have been

| wafhed away and carried down to the fea. Thus
= it may have afforded a temporary receptacle for

| the debris of the Alps, and may have ferved for

an entrepot, as it were, where thole debris were
A depofited,

364 ILLUSTRATIONS OF THE

depofited, before they were carried to the place

of their ultimate deftination. :

325. But the great depth which the lake hag
at prefent, {till remains to be explained, becaufe
no mud or gravel could be carried beyond the
gulf, of a thoufand feet deep, which was here
ready to receive it. The reality of this difi-
culty muft be acknowledged ; and fome caufe
feems to act, if not in the generation, yet cer-
tainly in the prefervation of lakes, with which
we are but little acquainted. We can indeed
imagine fome caufes of that kind to occur in
the courfe of the degradation of the land, which
may produce new lakes, or increafe the di-
mentions of the old. The wearing away of a

ratum, or body of ftrata, may lay bare, and
render acceffible to the water, fome beds of mi-
neral fubftances foluble in that fluid. The di-
ftrict, for inftance, in Chefhire, which contains
rock-falt, extends over a tract of fourteen or fif-
teen miles, and is covered by a thick ftratum
of clay, more or lefs indurated, which defends the
íalt from the water at the furface, and preferves
the whole mafs in a ftate of drynefs. Should
this covering be broke open by any natural con-
vulfion, or fhould it be worn away, as it muft
be in the progrefs of the general detritus, the
water would gain admiffion to the faline ftrata,
would

a E ENES NA

HUTTONIAN THEORY. 365

would gradually diffolve them, and form of
courfe a very deep and extenfive lake, where all
was before dry land. This event is not only
poflible, but it fhould feem, that in the courfe
of things it muft neceffarily happen.

326. Something of this kind may have taken
place in the track of the Rhone, and may have
_ produced the Leman Lake. It is not impoflible,
that, at a very remote period, the Rhone de-
feended from the Alps without forming any
lake, or at leaft any lake of which the remains
are now exifting ; and this fuppofition, which is
_ more probable than that of § 324, we fhall foon
find to be conformable to appearances of another
kind. The river may have wore away the fecon-
dary limeftone ftrata over which it took its
eourfe after it left the {chiftus of the mountains ;
and, in doing fo, may have reached fome ftra-
tum of a faline nature, and this being wafhed
out, may have left behind it a lake, which is but
modern compared with many of the revolutions
that have happened on the furface of thé earth *.

This explanation is no doubt hypothetical ;
but it is propofed in one of thofe cafes, in

which

* There are falt fprings at Bex, near Aigle, about
ten miles from the head of the lake: faline ftrata, there-
fore, are probably at no great diftance.

366 ILLUSTRATIONS OF THE

which hypothetical reafonings are warranted by
the ftricteft rules of philofophical inveftigation,
It is propofed in a cafe, where the caufes vifi-
ble to man feem inadequate to the effeé, and
where we muft therefore have recourfe to an
agent that is invifible. If the operations aferi-
bed to this agent are conformable to the analo- i
gy of nature, it is all that can in rekin be re-
quired.

327. Another circumftance may alfo influence
the generation and prefervation of lakes ; but it
is allo one with which we are but little ac.
quainted. The ftrata, and indeed the whole
body of mineral fubftances which forms the
bafis of our land, have been raifed up from the
bottom of the fea, by a progrefs that fhould feem
in general to have been gradual and flow. Ap-
pearances, however, are not wanting, which
fhew, that this progrefs is not uniform; and
that both rifing and finking in the furface
of the land, or in the rocks which are the
bale of it, have happened within a period of
time, which is by no means of great extent.
In this progrefs, the elevations and depreffions
may not be the fame for every fpot. They may
be partial, and one part of a ftratum, or body
of ftrata, may rife to a greater height, or be
more depreffed, than another. It is not impof-
fible, that this procefs may affed the depth of

lakes,

HUTTONIAN THEORY. 367

“fakes, and change the relative level of their
Fides and bottom.
328. All lakes, however, do not involve the
difficulty which the preceding conjectures are in«
tended to remove. The great lakes of North

F America do not, for inftance, receive their fup-

i ply from very large rivers. Of courfe, it is not

from a tract great in comparifon of themfelves,

| that the wafte and detritus is brought down

l into them; and it feems not at all wonderful,

in that, without being filled up, they have been

f able to receive it. The fame, in a degree at
~ leaft, is true of many other lakes.
It fhould alfo be contidered, that we may

im) err greatly in the eftimate we make of the ma-

f terials actually carried down and depofited in
i! any lake. To judge of their entire amount, we
@ © thould know the original form of the inequali-
Pan 7 ties on the earth’s furface ; of the quantity of de-

_ preffion which exifted, independently of the ri-

1m vers; and though, in general, thefe original ine-

qualities may be overlooked, and the prefent
_ confidered as made by the running of water,

4 yet, in particular inftances,.this may be far from
4 true. The Vallais, for example, which we con-

fider as the work of the Rhone, may, when the
‘Alps rofe out of the fea, have included many

(| depreflions of the furface, which the river join-

ed together, and, from being a feries of lakes,
_. formed into one great valley.
329. The

368 ILLUSTRATIONS OF THE

< 329. The mouths by which rivers on bold
rocky coafts difcharge their waters into the fea,
afford a very ftriking confirmation of the con.
clufions concerning the general fyftem of wafte
and degradation which have been drawn above,
At thefe mouths we ufually fee, not only the
bed of the river, but frequently a confiderable
valley, cut out of the folid rock, while that rock
perlerves its elevation, and its precipitous afped,

wherever it is not interfected. by a run of water.
No convulfion that can have torn afunder the ©
rocks; no breach that can have been madein

them, antecedent to the running of the waters,
will account for the circumftance of every ri-
ver finding a correfponding opening, by which
it makes its way to the fea; for that opening

being fo nearly proportional to the magnitude —

of the river, and for fuch breaches never oc-
curring but where ftreams of water are found.
330. The actual furvey of any bold and rocky
coaft, will make this clearer than any general
ftatement can poffibly do. Let us take, for an
example, the coaft of the Britifh Channel, from
Torbay to the Land’s End, which is faced by @
continued rampart of high cliffs, formed of
much indurated and primeval rock. If we con-
fider the breaches in this rampart, at the mouths
Q

EAER E Te

y a ron gy!
fnk
M hiat can have benng
tto the ranning of then,

the circumttance of m `

ponein: opening, bi
to the fa; for thtye
‘opal to the oat
for foch breaches m
of water at?
ant

HUTTONIAN THEORY. 369
of the Dart, of the Plym and Tamer, of the ri-
yer at Fowey, of the Fal, the Hel, &c. it will ap-
pear perfedtly clear, that they have been produ-
ced by their refpective ftreams. Where there
js no ftream, there is no breach in the rock, no
foftening in the bold and ftern afpe& which
this fhore every where prefents to the ocean.
If we look at the {maller ftreams, we find them
working their way through the cliffs at the pre-
fent moment; and we fee the fteps by which
the larger valleys of the Dart and the Tamer
have been cut down to the level of the fea. If
we would have {till clearer evidence, that no
breaches made antecedently to the running of
the rivers have opened a way for them, we need
only look to the oppofite fide, or northern fhore,
of the fame promontory, where we alfo find a
feries of outlets, all originating in the ridges of
the country, and becoming deeper as they ap-
proach the fea, but altogether unconnect: d with
the openings on the fouth fide ; and this could
hardly have been the cafe, had they been the
effects of previous concuffions, or of any pecu-

liarity in the original ftruCture of the rocks.
331. In contemplating fuch coafts as thefe,
When we go back to the time when the rivers ran
upon a level as high as the higheft of the cliffs
on the fea-fhore, we muft fuppofe, that the land
then extended many miles farther into what is
Aa now

370 ILLUSTRATIONS OF THE

now occupied by the fea. When at Plymou
for inftance, the Tamer and the Plym flowed
the level of Mount Edgecombe or of Sta
Heights, if the rivers ran with a moder
declivity into the fea, the coat muft hi
advanced many miles beyond its prefent li
Thus the land, when higher, was alfo more |
tended, and the limits of our ifland in that ;
cient ftate, were doubtlefs very different fr
thefe by which it is at prefent circumf
bed. :

If with the fame views we confider any
ther of the bold coafts which the map of -
world prefents us with, we fhall quickly rema
that wherever a deep interfection of the fea
made into the land, as on the weftern fhores
our own ifland, or on thofe of Norway, a ri
runs in at the head of it, and points out by wl
means fuch inlets are formed, viz. by the uni
powers of the fea and of the land, the waters
the latter having opened the way by wh
thofe of the former have penetrated fo far i
the country. Ae

332. It is not meant affuredly to deny i
irregularities of the fea-coaft, as it may hi
originally exifted ; thefe irregularities no dot
determined the initial operations of that we
and decay, by which, in procefs of time, th
were themfelves entirely effaced. The line

c

HUTTONIAN THEORY. 39%

Ny, 3 our coafts may be compared to one of thofe
‘i. curves, which are fometimes treated of in the
A higher geometry, where the ordinates are func-

: tions, not only of their abfciffee, but alfo of the

. Dr $ time elapfed fince a certain epocha. The form of
i ; the curve at that epocha, or when the time began
R = to flow, correfponds to the original form of the

i Í fea-coaft, on its emerging from the ocean, and

_ | before the powers of wafting and decay had be-

` gun to act upon it. To fpeak ftri@ly, the ori-

| ginal figure, in both cafes, influences all the fub-

À ; fequent; but the farther removed from it} in
"VE point of time, the lefs is that influence; fo that,

+ * in phyfical queftions, and for the purpofe of fuch
Mii approximations as fuit the imperfeGtion of our
‘en knowledge, the confideration of ihe original

Nomi’ figure may be wholly left out.

Note xvi. § 105.

Remains of Decompofed Rocks.

Ps 33. Tue plain of Crau was the Campus La-

im i _pideus of the ancients; and, as mythology al-

_ ways feeks to connect itfelf with the extraordi-

y J Mary faéts in natural hiftory, it was faid to be
es? y| the {pot where Hercules, fighting with the fons

Aa2 of

3472 ILLUSTRATIONS OF THE

of Neptune, and being in want of weapons, was
fupplied from heaven by a fhower of ftones:
hence it was called Campus Herculeus.

This plain is on the eaft fide of the Rhone,
between Salon and Arles: it is of a triangu-
lar form, about twenty fquare leagues in ex.
tent, and is covered almoft entirely with quart.
zy gravel. ‘This immenfe collection of gra-
vel has been fuppofed by fome to have been
brought down by the Durance from the Alps
of Dauphiny; by others it has been afcribed
to the Rhone; and by many to the fea, as
being a work too great for any river. The
explanation mentioned above, 4 105, namely,
that the loofe gravel on the plain arifes from
the decompofition of a great ftratum of pudding-

ftone, which is the bafis of the whole, is the —

opinion of Sauffure, and is founded on his own
obfervations *.

334. The theories that have been contrived for
explaining the phenomena of the plain of Crau,
afford an inftance of the neceflity of generaliz-
ing our obfervations before we can explain a par-
ticular appearance: in other words, they prove

the

* See Voyages aux Alpes, tom. iii. § 1592, et 1597:
See alfo on this fabje@ a Memoir by Lamanon, Journal
de Phyfique, tom. xxii. p. 477; and another by M. De
Servieres, zbzd. p. 270.

be h
meat for any im,
Mi above, 4 10, m
pared on the plain xiki
p ofa great ratono pi
the babs of the wh!
pre, aad is founded cal

nf

se that have been .
3 of the pat
peeli #
Ia!

fore we can ep

: a” wots
„jp 0 l

HUTTONIAN THEORY. 373
the truth of Lord Bacon’s maxim, That the ex-
planation of a phenomenon fhould not be fought
for from the ftudy of that phenomenon alone, but
from the comparifon of it with others. One of
the theories of this plain is, that the breccia,
which’ is the bafe of it, is formed from the con-
folidation of the loofe gravel of the plain, by
water percolating through it, and carrying fome
cementing fubftance along with it, or fome Za-
pidific juice, as it is called. And indeed, whe-
ther the gravel is formed from the breccia, or
the breccia from the gravel, is a queftion which
probably could never be refolved by the mere
examination of the plain itfelf. But the que-
ftion is very foon decided, when we compare
what is obferved here with other appearances
in the natural hiftory of the earth’s furface, and
confider how much more frequent the decom-
pofition of folids is, than their reconfolidation,
in any place above the level of the fea.

335. The argument for the decompofition of
ftony fubftances which is afforded by the ftate of
this fingular plain, may be confirmed by the ap-
pearances obferved in many extenfive traéts of
land all over the world, and efpecially in fome
parts of Great Britain. The road to Exeter from
Taunton Dean, between the latter and Honiton,
paffes over a large heath or down, confiderably

elevated above the plain of Taunton. The rock

> which

374. ILLUSTRATIONS OF THE

which is the bafe of this heath, as far as can be
difcovered, is limeftone, and over the furface
of it large flints, in the form of gravel, are
very thickly fpread. There is no higher ground
in the neighbourhood from which this gravel
can be fuppofed to have come, nor any ftream
that can have carried it, fo that no explanation
of it remains, but that it is formed of the flints
contained in beds of limeftone, which are now
worn away. ‘The flints on the heath are pre-
cifely of the kind found in limeftone; ma-
ny of them are not much worn, and cannot
have travelled far from the rock in which
they were originally contained. It feems cer-
tain, therefore, that they are the debris of lime-
ftone ftrata, now entirely decompofed, that once
lay above the ftrata which at prefent form
the bafe of this elevated plain, and proba-
bly covered them to a confiderable height.
This explanation carries the greater probability
with it, that any other way of accounting for
the fac in queftion, as the travelling of the gra-
vel from higher grounds, or the immerfion of
the furface under the fea, will imply changes
in the face of the country, incomparably greater
than are here fuppofed. Our hypothefis feems
to give the minimum of all the kinds of change
that can pofiibly account for the phenomenon.
330. The

HUTTONIAN THEORY. 375

TA d © 336. The fame remarks may be made on the
f° high plain of Blackdown, which the road paffes
hy, _ over in going from Exeter to the weftward. The
thy.’ flints there are diffeminated over the furface as
? À thickly as in the other inftance, and can be ex-

an 4 plained only on the fame fuppofition.

, 4 — Again, in the interior of England, beginning
MAU from about Worcelter and Birmingham, and
iy _ proceeding north-eaft through Warwickhhire,

AN a ] Leicefterfhire, Nottinghamfhire, as far as the

Miglin fouth of Yorkthire, a particular {pecies of high-
ly ly indurated gravel, formed of granulated

quartz, is found every where in great abun-
| dance. This fame gravel extends to the weft
nf 3 and north-weft, as far as Afhburn im Der-

“iy. bythire, and perhaps {till farther to the north.

»| The quantity of it about Birmingham is very

yj. Temarkable, as well as in many other pla-
wy fes; and the phenomenon is the more fur-
< a prifing, that no rock of the fame fort is. feen in

14, its native place. It is fuch gravel as might be
| i expected in a mountainous country, in Scotland,
A] for inftance, or in Switzerland, but not at all in

m® the fertile and fecondary plains of England.

"| This enigma is explained, however, when it
‘| is obferved, that the bafis of the whole tra@
juft defcribed is a red fandftone, often contain-
ing in it a hard quartzy gravel, perfe@ly fimilar
to that which has juft been mentioned. From
i Aag the

370 ILLUSTRATIONS OF THE

the diffolution of beds.of this fandftone, which -

formerly covered the prefent, there can be no
doubt that this gravel is derived. But, as the
gravel is in general thinly difperfed through
the fandftone, and abounds only in fome of its
layers, it fhould therefore feem, that a vaft bo.
dy of {trata muft have been worn away and de-
compoted, before fuch quantities of gravel as

now exift in the foil could have been let loofe,
337. I have faid, that a rock capable of afford:
ing fuch gravel as this, is not to be found in the
tract of country juft mentioned. This, however,
is not ftri@ly true; for in Worcefterthire, be-
tween Bromefgrove and Birmingham, about
feven miles from the latter, a rock is found
confifting of indurated ftrata, greatly eleva-
ted, and without doubt primitive, from the
detritus of which fuch gravel as we are now
{peaking of might be produced. Thefe ftrata
feem to rife up from under the fecondary, where
they are: interfected by the road; and, for as
much as appears, are not of great thicknefs, fo
that they cannot have afforded the materials of
this gravel dire@ly, though they may have donë
fo indirectly, or through the medium of the red
fandftone ; that is to fay, a primary rock of
which they are the remains, may have afforded
materials for the gravel in the .andftone ; and this
fandftone may in its turn have afforded the ma-
terials

HUTTONIAN THEORY. 377

l 4 4 terials of the prefent foil, and particularly the
) gravel contained in it.

338. Pudding-ftones being very liable to de-
compofition, have probably, in moft countries,

af afforded a large proportion of the loofe gra-

yel now found in the foil. The mountains,
or at leaft hills, of this rock, which are found in
many places, prove the great extent of fuch de-
compofition. Mount Rigi, for inftance, on the
fide of the Lake of Lucerne, is entirely of pud-
ding-ftone, and is 742 toifes in height, meafured

— i from the level of the lake. By the defcriptions
_ it given of it, as well as of other hills of the fame

kind in Switzerland, we may, without due at-

‘Mk ; tention, be led to fuppofe that they are entirely

1 formed of loofe gravel. Even M. Sauflure’s de~-

| feription is chargeable with this fault, though,

when attended to, it will be found to contain
a fufficient proof, that this hill is compofed of
real pudding-ftone*. The nature of the thing

‘i i alfo, would be fufficient to convince us, that a

hill, more than 4000 feet in height, could not

- eonfift of loofe and unconfolidated materials.
“If, then, we regard Mount Rigi as the re-
ains of a body of pudding-ftone firata, we mutt
conclude, that thefe {trata were originally more
extenfive, and the adjacent valleys and plains will
; ferve,

* Voyages aux Alpes, tom, iv. § 1941s

378 ILLUSTRATIONS OF THE

ferve, in fome degree, to meafure the quantity
of them which time has deftroyed.

339. If the theory of unftratified mountains,
namely thofe of whinftone, porphyry, and gra.
nite, be admitted as laid down above, it will
furnifh a meafure of the deftru€tion which has
taken place in the ftratified rocks, and of the
vaft depredations which have been made upon
them fince they were raifed up from the bottom
of the fea. - Like every other meafure, however,
of wafting, by a thing that is itfelf fubje@ to
wate, it. can only give a minimum, or a limit
which the quantity wafted muft neceflarily ex-
ceed.

The abrupt face of a whinftone rock muft be
underftood as an evidence, that fome body of
ftrata which fupported it when fluid, remain-
ed in contact with it, when it was become fo-
lid; and if this part of the mould in which
the whinftone was caft, has difappeared, it
muft generally be afcribed to the operation
of wafte and decompofition. Such a face,
for inftance, as that which Salifbury Craig pre-
fents tothe weft, viz. a perpendicular wall ef whin-
ftone, about ninety feet high, raifed on a body of
fandftone ftrata of the height of about 300 feet,
can have been produced only by having been abut-
ted againft fome ftratified rock, equally abrupt,

and

~HUTTONIAN THEORY. 379

and of the fame elevation with itfelf. Of this
rock no part remains. :

The bafaltic rock of Edinburgh Caftle is near-
ly in the fame ftate. Its perpendicular fides on
the fouth, weft, and north, are now difengaged
from the ftrata by which they were once en-
compafied.

340. The granite mountains alfo, where they
are quite unftratified, give rife to the fame con-
clufion. Thofe central chains which we find in
fo many inftances towering above the {chiftus
which cover their fides, have probably been
once completely enveloped by the latter , and, on
this fuppofition, an eftimate may fometimes be
formed of the original height of fuch mountains.

_ In thefe eftimations, however, fome uncer-

tainty muft arife, from our being unable to di-
ftinguifh between the effects which are to be
aferibed to the fracture and diflocation that
took place when the compound body of ftrati-
fied and unftratified rocks was raifed up from
the bottom of the fea, and the effects produced
by the fubfequent wafte and decompofition at the
furface.- In this, as in many other inftances,
we are not always able to feparate between the
original inequalities of the furface, and thofe
which wearing has produced.

341. It would be important to afcertain the rate

_. atwhichthe elevation of mountains decreafes, and

this

386 ILLUSTRATIONS OF THE

this is what we may perhaps expect to be aga
complithed, by the progrefs of geological {cience,
and the multiplying of accurate obfervations,
It has been fuppofed, that the Pyrenees dimi.
nifh about ten inches ina century ; but what
confidence is to be put in this eftimate, I am
unable to determine *,

A very unequivocal mark of the degradation
of mountains is often to be met with in the
heaps of loofe ftones found on their tops. Thefe
ftones, it is obvious, cannot have come from any
other place by natural means, and they are ac-
cordingly always fharp and angular, and have
none of the charaéters of tranfported rocks;
They are faid fometimes to have been brought
by men’s hands ; but this is highly improbable,
their quantity is often fo confiderable, and the dif.
ficulty of tranfportation fo great. Where any pur-
pofe was to be ferved by heaping them together,
men have availed themfelves of the ftones that
they found ready prepared on the fummit, and
have conftru@ted from them cairns, which have
ferved as fignals, ufeful in their paftoral, and
fometimes in their military occupations.

Note

* Effai fur le Mineralogie des Pyrenées, p. 87.

-HUTTONIAN THEORY.

Nore XVIIL § 112.

Tranfportation of Stones, Se.

342. Nature fupplies the means of tracing
with confiderable certainty the migration of fof-
fil bodies on the furface of the earth, as only the
more indurated ftones, and thofe moft ftrongly
characterifed, can endure the accidents that muft
befal them in travelling to a diftance from their
native place. |

wl -Itis a fa@ very generally obferved, that

where the valleys among primitive mountains
open into large plains, the gravel of thofe plains
confifts of ftones, evidently derived from the
mountains. The nearer that any fpot is to the
mountains, the larger are the gravel ftones, and
the lefs rounded is their figure ; and, as the di-
ftance increafes, this gravel, which often forms
a ftratum nearly level, is covered with a thick-
er bed of earth or vegetable foil. This pro-
greffion has particularly been obferved in the
valleys of Piedmont and the plains of Lombardy,
where a bed of gravel forms the bafis of the foil,
from the foot of the Alps to the fhores of the
Hadriatic,

382 ILLUSTRATIONS OF THE

Hadriatic *. We may colleé& from GUETTARD,
that a fimilar gradation is found in the gravel
and earth which cover the great plain of Poland,
from Mount Krapack to the Baltic +. The rea.
fon of this gradation is evident ; the farther the
ftones have travelled, and the more rubbing
they have endured, the fmaller they grow, the
more regular is the figure they affume, and the
greater the quantity of that finer detritus which
conititutes the foil. The wathing of the rains
and rivers is here obvious; and each of the
three quantities jat mentioned, if not diredtly
proportional to the diftance which the ftones
have migrated from their native place, may be
faid, in the language of geometry, to be at leaft
proportional to a certain function of that diftance,
343. The immenfe quantity of cailloux roulés,
or rounded gravel, collected in the immediate vi-
cinity of mountainous tracts, has led fome geo-
logifts to fuppofe the exiftence of ancient cur-
rents, which defcended from the mountains, in
a quantity, and with a momentum, of which there
is no example in the prefent. ftate of the world.
Thus Sauffure imagines, that the hill of Su-
pergue, near Turin, which is formed of gravel,
can only be explained by fuppofing fuch cur-
rents

* Voyages aux Alpes, tom. iii. § 1315.

+ Mém. Acad. des Sciences, 1762, p. 234; 293, &c-

HUTTONIAN THEORY. 383

yents as are juft mentioned, or what he terms a
debacle, to have taken place at fome former pe-
riod *. If, however, we afcribe to the moun-
tains a magnitude and elevation vaftly greater
than that which they now poffefs ; if we regard
the vallies between them as cut out by the ri-
yers and torrents from an immenfe rampart of
folid rock, neither materials fufficiently great,
nor agents fufficiently powerful, will appear to

I be wanting, for collecting bodies of gravel and

other loofe materials, equal to any that are found
onthe furface of the earth. The necefflity of

W introducing a debacle, or any other unknown

agent, to account for the tran{portation of foffils,
feems to arife from under-rating the effects of

of that dit _ action long continued, and not limited by fuch

j

fhort periods as circumfcribe the works, and

f even the obfervations, of men.

344. The fupply of gravel and cailloux roulés,
for the plains extended at the feet of primitive
mountains, is doubtlefs in many cafes much in-
creafed by the pudding-ftone, interpofed between
the fecondary and the primary ftrata. The beds of
pudding-ftone contain gravel already formed on
the fhores of continents, that ceafed to exift before.
the prefent were produced; and the cement of

this

D

¥ Voyages aux Alpes, tom, iii. § 1303.

384 ILLUSTRATIONS OF THE

this gravel, yielding eafily to the weather, al,
lows the ftones included in it to be wafhed down
by the torrents, and fcattered over the plains,
I know not if the hill of Supergue, above men.
tioned, is not in reality a mafs of the pudding.
ftone which forms the border of the Alps, and
of which the materials have fuffered no tranf.
portation fince the time of their laft confolida.
tion. This at leaft is certain, that Sauffure, not.
withftanding his accuracy, has fometimes con-
founded the loofe gravel on the furface with
that which is confolidated into rock ; an inace
curacy which is to be charged, as I have elfe.
where obierved, rather againft his fyftem than
himfelf.

345. The loofe ftones found on the fides of
hills, and the bottoms of valleys, when tra-
ced back to their original place, point out
with demonftrative evidence the great chan-
ges which have happened fince the com-
mencement of their journey; and in particular
ferve to fhow, that many valleys which now
deeply interfect the furface, had not begun to
be cut out when thefe ftones were firft detached
from their native rocks. We know, for inftance,
that ftones under the influence of fuch forces
as we are now confidering, cannot have firft de-
{cended from one ridge, and then afcended on .
the fide of an oppofite ridge. But the me

ol

HUTTONIAN THEORY. 385

of Mont Blanc has been found, as mentioned
above, on the fides of Jura, and even on the fide
of it fartheft from the Alps. Now, in the pre-
fent ftate of the earth’s furface, between the
central chain of the Alps, from which thefe
pieces of granite muft have come, and the ridge
_ of Mont Jura, befides many fmaller valleys, there
is the great valley of the Rhone, from the bot-
tom of which, to the place where they now lie,
isa height of not lefs than 3000 feet. Stones
F could not, by any force that we know of, be
U made to afcend over this height. We mut

_ therefore fuppofe, that when they travelled from

Mont Blanc to Jura, this deep valley did not
= f exif, but that fuch a uniform declivity, as water
i) can run on with rapidity, extended from the
ff one fummit to the other. This fuppofition ac-

_ cords well with what has been already faid con-

i) © cerning the recent formation of the Leman Lake,

@ and of the prefent valley of the Rhone.
i 346. We can derive, in a matter of this fort,
but little aid from calculation; yet we may

Tai - difcover by it, whether our hypothefis tranf-
À ull greffes materially againft the laws of probabi-
ag) lty, and is inconfiftent with phyfical principles
d already eftablifhed. The horizontal diftance

f _ from Mont Jura to the granite mountains, at the

f head of the Arve, may be accounted fifty geo-

bb graphic

386 ILLUSTRATIONS OF THE |

graphic miles. Though we fuppofe Mont Blane,
and the ref of thofe mountains, to have been ori-
ginally much higher than they are at prefent, the
ridge of Jura muft have been fo likewHfe; and
though probably not by an equal quantity, yet
it is the fairefk way to fuppofe the difference of
their height to have been nearly the fame in for-
mer ages that it is at prefent, and it may there-
fore be taken at 10,000 feet. The declivity of
a plane from the top of Mont Jura to the top of
Mont Blanc, would therefore be about one mile
and three quarters in fifty, or one foot in thirty;
an inclination much greater than is neceffary for
water to run on, even with extreme rapidity,
and more than fufficient to enable a river ora
torrent to carry with it ftones or fragments of
rock, almoft to any diftance.

Sauffure, in relating the fa& that pieces of
granite are found among the high paffes near
the fummits of Mont Jura, alleges, that they
are only found in fpots from which the central
chain of the Alps may be feen. But it fhould
feem that this coincidence is accidental, be-
caufe, from whatever caufe the tranfportation
of thefe blocks has proceeded, the form of the
mountains, efpecially of Mont Jura, muft be too
much changed to admit of the fuppofition, that
the places of it from which Mont Blanc is now

vifible,

HUTTONIAN THEORY. 387

vifible, are the fame from which that mountain
was vifible when thefe ftones were tran{ported hi-
ther. It may be, however, that the paffes which
now exift in Mont Jura are the remains of val-
leys or beds of torrents, which once flowed weft-
ward from the Alps; and itis atural, that the
fragments from the latt r m untains fhou d be
found in the neighbourhood of thofe ancient
water-tracks. :
347. Sauffure obferved in another part of
the Alps, that where the Drance defcends
from the fides of Mont Velan and the Great St
Bernard, to join the Rhone in the Vallais, the
valley it runs in lies between mountains of pri-
mary {chiftus, in which no granite appears, and
yet that the bottom of this valley, toward its
lower extremity, is for a confiderable way co-
vered with loofe blocks of granite *. His fa-
miliar acquaintance with all the rocks of thofe
mountains, led him immediately to fulpect, that
thefe ftones came from the granite chain of
Mont Blanc, which is weftward of the Drance,
and confiderably higher than the intervening
mountains. ‘his conjecture was verified by the
obfervations of one of his friends, who found
the ftones in queftion to agree exactly with a
Bb2 rock

iaa

* Voyages aux Alpes, tom. il. § 1042.

388 ILLUSTRATIONS OF THE

rock at the point of Ornex, the neareft part of
the granite chain.

In the prefent ftate of the furface, however,
the valley of Orfiere lies between the rocks of
Ornex and the valley of the Drance, and would
certainly have intercepted the granite blocks in
their way from the one of thefe points to the
other, if it had exifted at the time when they
were pafling over that tra. The valley of Or-
fiere, therefore, was not formed, when the tor-
rents, or the glaciers tranfported thefe fragments
from their native place.

Mountainous countries, when carefully ex-
amined, afford fo many fats fimilar to the pre-
ceding, that we fhould never have done were
we to enumerate all the inftances in which they
occur. ‘They lead to conclufions of great ufe,
if we would compare the machinery which na-
ture actually employs in the tranfportation of
rocks, with the largeft fragments of rock which
appear to have been removed, ‘at fome former
period, from their native place.

348: For the moving of large maffes of rock,
the moft powerful engines without doubt which
nature employs are the glaciers, thofe lakes or —
rivers of ice which are formed in the higheft
valleys of the Alps, and other mountains of the
firft order. Thefe great maffes are in perpetual

motion,

wt, : HUTTONIAN THEORY, 369

the lug 3 = motion, undermined by the influx of heat from
i bety t, hn, the earth, and impelled down the declivities on
ia teng _ which they reft by their own enormous weight,
s S together with that of the innumerable fragments
of rae of rock with which they are loaded. I hefe
ak ty fragments they gradually tran{port to their ut-
* tea moft boundaries, where a formidable wall alcer-
e valey tains the magnitude, and attefts the Ore; of the
great engine by which it waserected. ‘The im-
ported thet fy menfe quantity and fize of the rocks thus tranf-
w ported, have been remarked with aftonifhment
by every obferver *, and explain fufficiently how
fragments of rock may be put in motion, even
where there is but little declivity, and where the
actual furface of the ground is confiderably un-
even. In this manner, before the valleys were cut
out in the form they noware, and when the moun-
tains were {till more elevated, huge fragments of
rock may have been carried toa great diftance; and
it is not wonderful, if thefe fame maffes, greatly
diminifhed in fize, and reduced to gravel or fand,
have reached the fhores, or even the bottom, of
the ocean.

349. Next in force to the glaciers, the torrents
are the moft powerful inftruments employed in
Bb 3 the

* The ftones collected on the Glacter de Miage, when
Sauflure vifited it, were in fuch quantity as to conceal

the ice entirely. Voyages aux Alpes, tom. ii, § 554.

390 ILLUSTRATIONS OF THE

the tranfportation of ftones. Thefe, when they
defcend from the fides of mountains, and even
where the declivity of their courfe is not very
great, produce effes which nothing but dire@
experience could render credible. The frag-
ments of rock which oppofe the torrent, are ren-
dered fpecifically lighter by the fluid in which
they are immerfed, and lofe by that means at
leaft a third part of their weight: they are, at
the fame time, impelled by a force proportional
to the fquare of the velocity with which the
water rufhes againft them, and proportional alfo
to the quantity of gravel and ftones which it
has already put in motion. Perhaps, after ta-
king all thefe circumftances into computation,
in the midft of a fcene perfe@ly quiet and undi-
fturbed, a philofopher might remain in doubt as
to the power of torrents to move the enormous
bodies of rock which are feen in the bottom of
the narrow valleys or deep glens of a mountain-
ous country ; but his incredulity, fays an expe-
rienced traveller, will ceafe altogether, if he has
been furprifed by a ftorm in the midft of fome
Alpine region; if he has feen the number and
impetuofity of the cataracts which rufhed down
the fides of the mountains, and beheld the ruin
which accompanied them ; and if, when the tem-
peft was paffed, he has viewed thofe meadows,

which

HUTTONIAN THEORY. 391

which a few hours before were covered with
verdure, now buried under heaps of ftones, or
overwhelmed by maffes of liquid mud, and
the fides of the mountains cut by deep ravines,
where the track of the fmalleft rivulet was not
before to be difcovered *.

It is but rarely, however, even on occafions
like thefe, that fuch vaft maffes of rock can be
feen actually in motion, as are often found on
the furface, apparently removed to a great di-
ftance from their native place. The magnitude
of thefe is fo great, in many inftances, that their
tran{portation cannot be explained without fup-
pofing, that the furface was very different when
thefe tranfportations took place from what it is
at prefent ; that the elevation of the mountains
was greater, and the ground {moother and more
uniform, at leaft in fome directions. If thefe
fuppofitions are admitted, and they are counte-
nanced, as we have already feen, by almoft every
phenomenon in geology, the difficulties which
prefent themfelves here will not appear infur-
mountable. |

350. One of the largeft blocks of granite that
we know of, is on the eaft fide of the lake of

Bb4 Geneva,

* See an account of a thunder ftorm near Bareges, in

the Effai fur la Mineralogie des Pyrenées, p. 134.

392 ILLUSTRATIONS OF THE

Geneva, called Pierre de Gouté, about ten feet
in height, with a horizontal feétion of fifteen by
twenty *. Another block not far from it, and
nearly of the fame fize, has fome remains of
{chiftus attached to it. Thefe ftones very much
refemble thofe which have fallen from the
Aiguilles, in the valley of Chamouny. The di-
ftance from their prefent fituation to thofe 4i-
guilles is about thirty Englith miles, with many
mountains and valleys at prefent interpofed.
By whatever means, therefore, thefe blocks were
tran{ported, their motion muft have been over a
furface of much more uniform declivity than the
prefent. If the furface was without great ine-
qualities, and its general declivity about one
foot in thirty, as already computed, the gla-
ciers, in the firft place, and the torrents after-
wards, may have ferved for the tranfportation
even of thefe rocks. |
351. Again, in the narrow vale or glen which
feparates the Great from the Little Saleve, the ftra-
ta are all calcareous, but a great number of loofe
blocks of granite and primary {chiftus are {catter-
ed over the furface. A block of the former, near
the lower end of the valley, is about the fize of
1200 cubic feet. Two other large blocks of the
fame kind of ftone reft on a bafe of horizontal

limeftone,

/* Voyages aux Alpes, tom. i. § 308.

HUTTONIAN THEORY. 303

limeftone, elevated two or three feet above the
ret of the furface. This elevation arifes no
doubt from the protection which the ftones have
afforded to the calcareous beds on which they
lie, fo that thefe beds do not wear away fo
faft as thofe which are fully expofed to the
weather. But it is furely to take a very limited
view of the operations on the furface, to fup-
pofe, with Saufflure, that the parts of the cal-
careous rock under thefe ftones has fuffered
no wafte whatfoever, fo that the ftones remain
now in the identical fpot where they were pla-
ced by the great debacle which brought them
down from the high Alps *. For my part, I have
no doubt that the Arve, which is ftill at no great
= diftance, when it ran on a higher level, and in
_ a line different from the prefent, aided by the

i) glaciers and fuperior elevation of the mountains,

was an engine fufficiently powerful for effe&ing
the tranfportation of thefe ftones.

352. Thefe phenomena are not peculiar to the
Alps, but prevail, in a greater or lefs degree, in
the vicinity of all primary or granite mountains.
In the ifland of Arran, a fragment of the fame
kind with that which conftitutes the upper part
of Goatfield, is found on the fea-fhore, at leaft
three miles from the neareft granite rock, and

with

Mee

* Ibid. § 227.

394 ILLUSTRATIONS OF THE

with a bay of the fea intervening. Its dimen:
fions are not far from thofe of the pierre de
gouté. In fome former ftate of the granitic
mountains in that ifland, the declivity from the
top of Goatfield may have been very uniform,
and more rapid than it is at prefent.

333. Befides glaciers and torrents, which have
no doubt been the principal inftruments in produ-
cing thefe changes, other caufes may have oc-
cafionally operated. Large ftones, when once
detached, and refting on an inclined plane, from
the effects of wafte and decompofition, may ad-
vance horizontally, at the fame time that they
defcend perpendicularly, and this will happen
though they be not urged by any torrent, or any
thing but their own weight ; for the furface of
the ground, as it waftes, remains higher un-
der the ftone, and for a little way round it,
than at a greater diftance, on account of the
protection which it receives from the ftone,
as in the inftances at Saleve, juft mention-
ed. The ftone itfelf alfo becomes rounded at
the bottom; and thus the furface in contact
with the ground is diminifhed in extent, and
the two furfaces rendered convex towards
one another. It muft therefore happen, that

the fupport, continually weakening, will at

length give way, and the ftone incline or roll
toward the lower fide, and may even roll con-
fiderably,

pk er

HUTTONIAN THEORY. 395

fiderably, if its centre of gravity has been high
above its point of fupport, and if its furface has
had much convexity: Thus the horizontal may
very far exceed the perpendicular motion; and,
in the courfe of ages, the ftone may travel to a
great diftance. A ftone, however, which tra-
yels in this manner, muit diminifh as it pro-
ceeds, and muft have been much greater in the
beginning than it is at prefent.

354. This kind of motion may be aided by
particular circumftances. W hen a ftone refts on
an inclined plane, fo as to be in a ftate not very
remote from equilibrium, if a part be taken
away from the upper fide, the equilibrium will
be loft, and the ftone will thereby be put in mo-
tion. That ftones which lie on other ftones,
may, by wearing, be brought very near an equi-
librium, is proved by what are called rocking-
flones, or in Cornwall Logan /tones, which have
fometimes been miftaken for works of art; but
that are certainly nothing elfe than ftones,
which have been fubjected to the univerfal law
of wafting and decay, in fuch peculiar circum-
= ftances, as nearly to bring about an equilibrium

_ Of that ftable kind, which, when flightly difturb-
ed, re-eftablifhes itfelf*. The logan ftone at
the

* I do not prefume fo far as to fay, that all rocking.
ftones are produced by natural means: I have not fufli-
cient

396 ILLUSTRATIONS OF THE

the Land’s End, is a mafs of granite, weighing
more than fixty tons, refting on a rock of gra.
nite, of confiderable height, and clofe on the
fea-fhore. The two {tones touch but in a fmall
fpot, their furfaces being confiderably convex
towards one another. The uppermott is fo near-
ly in an equilibrium, that it can be made to vi.
brate by the ftrength of a man, though to over.
fet it entirely would require a valt force. This
arifes from the centre of gravity of the ftone
being fomewhat lower than the centre of cur-
vature of that part of it on which it has a ten-
dency to roll; the confequence of which is, that
any motion impreffed on the ftone, forces its
centre of gravity to rife, (though not very con-
fiderably), by which means it returns whenever |
the force is removed, and vibrates backward and
forward, till it is reduced to reft. Were it re-
quired to remove the ftone from its place, it
might

cient information to juftify that affertion ; but the great
fize of that at the Land’s End, its elevated pofition, and the
approaches toward fomething of the fame kind which
are to be feen in other parts of that fhore, prove
that it is no work of art. They who afcribe it to
the Druids, do not confider the rapidity with which
the Cornifh granite waftes, nor think how improbable
it is, that the conditions neceflary to a rocking-ftone,
whether produced by nature or art, fhould have remain-
ed the fame for fixteen or feventeen hundred years.

HUTTONIAN THEORY. 307

might be moft eafily done, by cutting off a part
from one fide, or blowing it away by gun-
powder ; the ftone would then lofe its balance,
would tumble from its pedeftal, and might roll
to a confiderable diftance. Now, what art is
here f{uppofed to perform, nature herfelf in time
will probably effet. If the wafte on one fide
of this great mafs fhall exceed that on the op-
pofite in more than a certain proportion, and it
is not likely that that proportion will be always
maintained, the equilibrium of the Logan ftone

` will be fubverted, never to return. Thus we

perceive how motion may be produced by the
combined action of the decompofition and gra~
vitation of large maffes of rock.

355. Befides the gradual wafte to which ftones
expofed to the atmo/phere are neceflarily fubje&,
thofe of a great fize appear to be liable to fplit-
ting, and dividing into large portions, no doubt
from their weight. This may be obferved in
almoft all ftones that happen to be in fuch cir-
cumftances as we are now confidering ; and from
this caufe the fubverfion of their balance may
be more fudden, and of greater amount, than
could be expected from their gradual decay.

Thus, if to the wafting of a {tone at the bot-
tom, we add the accidents that may befal it in
the wafting of its fides, we fee at leaft the phy-
fical poffibility of detached ftones being put in
motion,

398 ILLUSTRATIONS OF THE

motion, merely by their own weight. It is in,
deed remarkable, that fome of the largeft of thefe
ftones reft on very narrow bafes. Thofe at the
foot of Saleve touch the ground only in a few
points: The Boulder-ftone of Borrowdale is
fupported on a narrow ridge like the keel of a
fhip, and is prevented from tumbling by a ftone
or two, that ferve as a kind of fhores to prop it
up. Very unexpected accidents fometimes hap-
pen to difturb the reft of fuch fragments of
rock as have once migrated from their own
place. Sauflure mentions a great mafs of Zapis
gllaris *, that lies detached on the fide of a de-
clivity in the valley of Urferen, in the canton of
Uri. The people ufe this ftone as a quarry, and -
are working it away on the upper fide, in
confequence of which it will probably be foon
overfet, and will roll to the bottom of the val-
ley.

356. In many inftances it cannot be doubted,
that ftones of the kind here referred to are
the remains of maffes or veins of whinftone or
granite, now worn away, and that they have
travelled but a very fhort way, or perhaps not
at all, from their original place. Many of the
large blocks of whinftone which we find in this
country, fometimes fingle, and fometimes fcat-

tered

ee al

* Voyages aux Alpes, tom, iv. § 1851.

HUTTONIAN THEORY. 399

tered in confiderable abundance over a particu-
lar fpot, are certainly to be referred to this
caufe. But the moft remarkable examples of
this fort are the ftones found at the Cape of
Good Hope, on the hill called Paarlberg, which
takes its name from a chain of large round ftones,
like the pearls of a necklace, that paffes over the
fummit. Two of thefe, placed near the higheft
point, are called the Pearl and the Diamond,
and were mentioned feveral years ago in the Phi-
lofophical Tranfactions *. From a more recent
account, thefe ftones appear to be a fpecies of
granite, though the hill on which they lie is
compofed of fandftone ftrata}. The Pearl isa
naked rock, that rifes to the height of 400 feet
above the fummit of the hill; the Diamond is
higher, but its bafe is lefs, and it is more inac-
ceffible.

From the above ftones forming a regular
chain, as well as from the immenfe fize. of the
two largeft, it is impoflible to fuppofe that they
have been moved ; and it is infinitely more pro-

bable, that they are parts of a granite vein,

which runs acrofs the fandftone ftrata, and of
which fome parts have refitted the action of the
weather, while the reft have yielded to it. The

whole

* Vol. Ixvill. p. 102.

+ Barrow’s Travels into Southern Africa, p. 60.

4oo ILLUSTRATIONS OF THE

whole geological hiftory of this part of Africa
feems highly interefting, fince, as far as can be
collected from the accounts of the ingenious
traveller juft mentioned, it confifts of horizontal
beds of fandftone or limeftone, refting immediate-
ly on granite, or on primary fchiftus. Loofe
blocks of granite are feen in great abundance at
the foot of the Table Mountain, and along the
fea-fhore.

ee ea

357. The fyflem which accounts for fuch
phenomena as have been confidered in this and
fome of the preceding notes, by the operation of
a great deluge, or debacle as it is called, has
been already mentioned. In Dr Hutton’s theo-
ry, nothing whatever is afcribed to fuch acci-
dental and unknown caufes; and, though their
exiftence is not abfolutely denied, their effects,
whatever they may have been, are alleged to
be entirely obliterated, fo that they can be re-
ferred to no other clafs but that of mere pofi- _
bilities. A minute difcuffion, however, of the
queftion, Whether there are, on the furface of
the earth, any effects that require the interpo-
fition of an extraordinary caufe, would lead in-
to a longer digreffion than is fuited to this place.
I fhiall briefly fate what appear to be the prin-

cipal

In Dr Hotot
alcribed to fc iff
fes; and, thought
y denied, ther ;
been, ae alef

HUTTONIAN THEORY. AOL

cipal objections to all fuch explanations of the
phenomena of geology.

358. The general ftructure of valve among
mountains, is highly unfavourable to the notion
that they were produced by any fingle great tor-
rent, which {wept over the furface of the earth.
In fome inflances, valleys diverge, as it were
from a centre, in all directions. In others, they
originate from a ridge, and proceed with equal
depth and extent on both fides of it, plainly in-
dicating, that the force which produced them
was nothing, or evanefcent at the fummit of
that ridge, and increafed on both fides, as the
diftance from the ridge increafed. The work-
ing of water collected from the rains and the
fnows, and feeking its way from a higher to a
lower level, is the only caufe we know of, which
is fubje& to this law.

359. Again, if we confider a valley as a fpace,
which perhaps with many windings and irre-
gularities, has been hollowed out of the folid
rock, it is plain, that no force of water, fud-

‘denly applied, could loofen and remove the
great mafs of ftone which has actually difap-

peared. The greateft column of water that
could be brought to act againft fuch a mals,
whatever be the velocity we aferibe to it, could
not break afunder and difplace beds of rock
Many leagues in length, and in continuity with

Ce the

402 ILLUSTRATIONS OF THE

the rock on either fide of them. The flow work.
ing of water, on the other hand, or the powers
that we fee every day in aćłion, are quite fuff-
cient for this effect, if time only is allowed them.
360. Some valleys are fo particularly con-
ftructed, as to carry with them a ftill ftronger
refutation of the exiftence of a debacle. Thefe
are the longitudinal valleys, which have the
openings by which the water is difcharged,
not at one extremity, but at the broadfide,
Such is that on the eaft fide of Mont Blanc,
deeply excavated on the confines of the granite
and {chiftus rock, and extending parallel to the
beds of the latter, from the Col de la Segne to
the Col de Ferret ; its opening is nearly in the
middle, from which the Dorea iffues, and takes
its courfe through a great valley, nearly at right
angles to the chain of the Alps, and to the
valley jut mentioned. From the ftruéture of
thefe valleys, Sauffure has argued very juftly
againft Buffon’s hypothefis, concerning the for-
‘mation of valleys by currents at the bottom of the
fea*. It affords indeed a complete refutation of
that hypothefis ; and it affords one no lefs com-
plete of the fyftem which Sauffure himfelf feems
on fome occafions fo much inclined to fupport.
For if it be faid; that this valley was cut out by the
current

* Voyages aux Alpes, tom. il. § 920.

Eo

HUTTONIAN THEORY. 403

eurrent of a debacle, that current muft either
have run in the direction of the valley of Ferret,
orin that of the Dorea, which iffues from it. Ifit
had the direction of the firft, it could not cut out
the fecond ; and if it had the diretion of the fe-
cond, it could not cut out the firft. Befides, the
force which excavated this valley muft have been
nothing at the two extreme points, viz. at the Col
de Segne and the Col de Ferret, and muft have
increafed with the diftance from each. It can
have been produced, therefore, only by the run-
ning of two ftreams in oppofite directions, on a
furface that was but flightly uneven, thefe

"| ftreams at meeting taking a new dire@ion, near-

ly at right angles to the former. A clearer

) proof could hardly be required than is afforded
# inthis cafe, that what is now a deep valley was
"formerly folid rock, which the running of the
} waters has. gradually worn away; and that
p | the waters, when they began to run, were on
) alevelas high, at leaft, as the tops of thofe moun-
_ tains by which the valley is bounded toward
the lower fide.

361. Longitudinal valleys, with the water
burfting out tranfverfely from their fides, like the
preceding, are by no means confined to moun-
tains of the firft order. We have a very good
example, though on a fmall fcale, of a val-
ley of this fort, within a few’miles of Edin-

Cc2 burgh,

404 ILLUSTRATIONS OF THE

burgh. The Pentland Hills form a double ridge,
feparated by a {mall longitudinal valley, that
runs from N. E. to S. W., the water of which
iffues from an opening almoft in the middle,
and directed towards the fouth. This, there-
fore, is not the work of any great torrent, which
overwhelmed the country; for no one direc.
tion, which it is poflible to afflign to fuch a tor-
rent, will afford an explanation, both of the
valley and its outlet *. | |

362. They

* In Scotland there is one valley, of a kind that I be-
lieve is extremely rare in any part of the world, in ac-
counting for which, the hypothefis of a torrent or debacle
might, if any where, be employed to advantage. This is
the valley which extends acrofs the ifland, from Invernefs
to Fort-William, or from fea to fea, being open at both
ends, and very little elevated in the middle. It is nearly
ftraight,andofa veryuniform breadth,except that towards
each end it widens confiderably. The bottom, reckon- `
ing tranfverfely, is flat, without any gradual flope from
the fides towards the middle. From the fides the moun-
tains rife immediately, and form two continued ridges
of great height, like ramparts or embankments on each
fide of a large foflé. A great part of the bottom of this
fingular valley is occupied by lakes, namely, Loch
Nefs, Loch Oich, and Loch Lochy. Its length is about
fixty-two miles, and the point of partition from which
the waters run different ways, viz. north-eaft to the

German

aii

=

ee

HUTTONIAN THEORY. 405

362. They who maintain the exiftence of the
debacle, will no doubt allege, that though thele
i Ces valleys

German Ocean, and fouth-weft to the Atlantic, is be-
tween Loch Oich and Loch Lochy; and, by the eftima-
tion of the eye, I fhould hardly think that it is elevated
more than ten or fifteen feet above the furface of either
lake. The country on both fides is rugged and moun-
tainous, and the ftreams which defcend from thence
into the valley, either fall direétly into the lakes, or
turn off almoft at right angles when they enter the val-
ley. Though the bottom of this valley, therefore, is
every where alluvial, with the exception, perhaps, of a
few rocks which appear at the furface, it is certainly
not excavated by the rivers which now flow init. The
direction of the valley, it is to be obferved, is the fame
with that of the vertical ftrata which compofe the moun-
tains on either fide.

Here, then, we have a valley, not cut out by the

f working of any ftreams which now appear; and we

may therefore make trial of the hypothefis of a de-
bacle. This, however, will afford us no affiftance; be-
caufe, if we fuppofe what is now hollow to have been

once occupied by the fame kind of rock which is on

either fide, no force of torrents can have fuddenly loofen-
ed and removed from its place a body of fuch vaft mag-
nitude. A greater column of water, than one having
for its bafe a tranfverfe fection of the valley, could
hot act againft it, and this would have to overcome

the

406 ILLUSTRATIONS OF THE

valleys were not cut out by means of it, yet
others may. But it muft be recolleGed, that if
fome

the cohefion and inertia of a column of rock of the
fame fection, and of the length of fixty-two miles,
It is not hazarding much to affirm, that no velocity
which could be communicated to water, not even that
which it could acquire by falling from an infinite height,
could give to it a force in any degree adequate to this
great effect.

The explanation of this valley, which appears to me
the moft probable, is the following. It will be hewn
hereafter, that there is good reafon to fuppofe, that, in
moft parts of our ifland, the relative level of the fea and
land has been in paft ages confiderably higher than it is
at prefent. In fuch circumftances, this valley may have
been under the, furface of the fea, the higheft part of it
being fcarcely 100 feet above that level at prefent,
It may have been a kind of found, therefore, or ftrait,
which conneéed the German Sea with the Atlantic; and
the ftrong currents, which, on account of the different
times of high water in thefe two feas, muft have run al-
ternately up and down this ftrait, may have produced
that flatnefs of the bottom, and firaightnefs of the fides,
and that widening at the extremities, which are men-
tioned above. In this way, too, fome difficulties are re-
moved relative to Loch Nefs, which is fo deep as hard-
ly to be confiftent with the indefinite length of the
period of wafte that mutt be afcribed to the mountains
on each fide of it. Its depth is faid, where greateft, not

te

HUTTONIAN THEORY. 407

fome of the greateft and deepeft valleys on the
face of the earth, fuch as that juft mentioned,
on the eaft fide of Mont Blanc, are thus fhewn
to be the work of the daily wafting of the fur-
face, what other inequalities can be great enough
to require the interpofition of a more powerful
caufe? If a dignus vindice nodus does not exift
here, in what part of the natural hiftory of the
earth is it likely to be found?

363. The large maffes of rock fo often met with
at a diftance from their original place, are one of
the arguments ufed for the debacle. It has, how-
ever, been fhewn, that, fuppofing a form of the
earth’s furface confiderably different from the
prefent, efpecially, fuppofing the abfence of the
valleys which the rivers have gradually cut out,
the tranfportation of fuch ftones is not impoffi-

ble, even by fuch powers as nature employs at

prefent. Now, without the fuppofition that the
furface was more continuous, and that its pre-
fent inequalities did not exift, no force of tor-
rents, whatever their velocity and magnitude
may have been, could have produced this tranf-
portation. No force of water could raife a ftone
like the pierre de goutté from the bottom of a

Cc4 valley,

to be lefs than 18c fathoms. According to this hypo-
thefis, it may, at no very diftant period, have been a
part of the bottom of the fea.

408 ILLUSTRATIONS OF THE

valley, to the top of a fteep hill. Indeed,
if we fuppofe a great fragment of rock to
be hurried along on a horizontal or an inclined
plane, by the force of water, the moment it
comes to a deep valley, and has to rife up over
an afcent of a certain fteepnefs, it will remain at
reft ; the water itfelf will lofe its velocity, and the
heavy bodies which it carried with it will pro-
ceed no farther. Thus, therefore, we have the
following dilemma. If the furface is not fup-
pofed to have had a certain degree of uniformi-
ty in paft times, a debacle is infufficient for the
tran{portation of ftones : If it is fuppofed to have

had that uniformity, a debacle is unneceflary.
364. Another faé&, which has been fuppofed
favourable to the opinion of the action of great
torrents at fome former period, is, that in coun-
tries like that round Edinburgh, where whin-
ftone hills rife up from among fecondary ftrata,
a remarkable uniformity is obferved in the di-
reion of their abrupt faces. ‘Thus, in the
country juft mentioned, the fteep faces general-
ly front the weft, while, in the oppofite direction,
the flope is gentle, and the hills decline gradual-
ly into the plain. Hence it is fuppofed, that a
torrent, fweeping from weft to eaft, has carried
off the ftrata from the weft fide of thefe hills,
but, being obftruéted by the whinftone rock,
has

HUTTONIAN THEORY. 409

has left the ftrata on the eaft fide in their natu-

ral place.
But, befides that no force which can ever be

17 afcribed to a torrent could have removed at

once bodies of ftrata 300 or 400 feet, nay even
869 or 1000 in thicknefs, which muft have been

th. “tthe cafe if this were the true explanation of the

fact, there is a circumftance which may perhaps

enable us to explain thefe phenomena without

the afliftance of any extraordinary caufe. - The
fecondary ftrata in which the whinftone hills
are found in this part of Scotland, are not hori-
zontal, but rife or bead towards the weft, dip-
ping towards the eaft. The fide, therefore, of

i) the whinftone hills which is precipitous, is the

- fame with that towards which the ftrata rife.

imp Now, from the manner in which thefe hills are

fuppofed to have been elevated, the {trata are

te likely to have been moft broken and fhattered
aie towards that fide, while, on the oppofite, they
go) had the fupport of the whinftone rock. They
a) would become a prey, therefore, more eafily to

the common caufes of erofion and wafte on the
upper fide than onthe lower. The ftreams that
flowed from the higher grounds would wear
_ them on the former moft readily ; and the action
of thefe ftreams would be refifted by the fupe-
tior hardnefs of the whinftone, juft as the great
torrent of the debacle is {uppofed to have been,
It

410 ILLUSTRATIONS OF THE

It fhould alfo be obferved, that this fa& of
the uniform direCtion of the abrupt faces of
mountains, is often too haftily generalized. In
primitive countries, it is no farther obferved than
by the fteep faces of the mountains being moft
frequently turned toward the central chain. Ip
Scotland, as foon as you leave the flat country,
and enter the Highlands, the {carps of the hills
face indifcriminately all the points of the com-
pafs, and are directed as often to the eaft as to
the weft.

365, Where the ftrata are nearly horizontal,
they afford the moft diflin@ information concern-
ing the direction and progrefs of the wafting of the
land. The inclined pofition of the ftrata, which
in all other cafes muft enter for fo much into
our eftimate of the caufes which have produced
the prefent inequality of the earth’s furface, dif-
appears there entirely ; and the whole of that
inequality is to be afcribed to the operations at
the furface, whether they have been fudden or ©
gradual. A very important fact from a coun:
try of this fort, is related by Barrow, in his
Travels into Southern Africa, The moun-
tains about the Cape of Good Hope, and as far
to the north as that ingenious traveller profecu-
ted his journey, are chiefly of horizontal ftrata
of fandftone and limeftone, exhibiting the ap-
pearance, on their abrupt fides, of regular layers
of mafonry, of towers, fortifications, &c. Now,

among

HUTTONIAN THEORY. 41

among all thefe mountains, he obferved, that
the high or fteep fides look conftantly down
the rivers, while the floping or inclined fides
have juft the oppofite dire@tion. When, in tra-
yelling northward, he paffed the line of parti-
tion, where the waters from running fouth take
their direction to the north, he found, that the
gradual flope, which had hitherto been turned
to the north, was now turned to the fouth: The
abrupt afpect of the mountains, in like manner,
from facing the fouth, was directed to the north 5
fo that, in both cafes, the hills turned their backs
on the line of greateft elevation *.

It is evident, therefore, that the form of this
land has been determined by the flow working
of the ftreams. The caufes which produced the
effets here defcribed, began their action from
‘the line of greateft elevation, and extended it
from thence on both fides, in oppofite directions.
This is the moft precife character that can mark
the alluvial operations, and diftinguifh them from
the overwhelming power of a great debacle.

306. Laftly, If there were any where a hill, or
any large mafs compofed of broken and fhapelefs
ftones, thrown together like rubbifh, and neither
worked into gravel nor difpofed with any regu-
larity, we muft afcribe it to fome other caufe

than

e
* Barrow’s Travels into Southern Africa, p. 245.
s P245

412 ILLUSTRATIONS OF THE

than the ordinary detritus and wafting of the
land. This, however, has never yet occurred ;
and it feems beft to wait till the phenome-
non is obferved, before we feek for the explana-
tion of it.

367. Vhefe arguments appear to me conclufive
again{t the neceflity of fuppofing ‘the a&tion of
fudden and irregular caufes on the furface of the
earth. In this, however, I am perhaps deceived :
neither Pallas, nor Sauflure, nor Dolomieu, nor
any other author who has efpoufed the hypothefis
of {uch caufes, has explained his notions with any
precifion ; on the contrary, they have all fpoken
with fuch referve and myftery, as feemed to
betray the weaknefs, but may have concealed
the ftrength of their caufe. I have therefore
been combating an enemy, that was in fome re-
{pects unknown; and I may have fuppofed
him diflodged, only becaufe I could not pene-
trate to his ftrong-holds. The queftion, how-
ever, is likely foon to affume a more determinate
form. A zealous friend of Dr Hutton’s theory,
has lately * declared his approbation of the hy-
pothelis which has here been reprefented as fo
adverfe to that theory; and, from his ability and
vigour of refearch, it is likely to receive every
improvement of which it is fufceptible.

OTE

* Tranf, Royal Society Edin. vol. v. p. 68.

HUTTONIAN THEORY. 413

NOTE xix. § 117.

Tranfportation of Materials by the Sea.

368. Tue exiftence of the great and exten-
five operations, by which the {poils of the land
are carried all over the ocean, and fpread out
on the bottom of it, may be fuppofed to requiré
{fome further elucidation. We muf attend,
therefore, to the following circumftances.

When the detritus of the land is delivered
by the rivers into the fea, the heavieft parts are
depofited firft, and the lighter are carried to a
greater diftance from the fhore.. The accumu-
lation of matter which would be made in this
manner on the coaft, is prevented by the farther
operation of the tides and currents, in confe-
quence of which the fubftances depofited con-
tinue to be worn away, and are gradually re-
moved further from the land. The reality of
this operation is certain ; for otherwife we fhould
have on the fea-fhore a conftant and unlimited
accumulation of fand and gravel, which, being
perpetually brought down from the land, would
continually increafe on the fhore, if nature did
not employ fome machinery for removing the

advanced.

414 ILLUSTRATIONS OF THE

advanced part into the fea, in proportion to the
fupply from behind.

The conftant agitation of the waters, and the
declivity of the bottom, are no doubt the caufes
of this gradual and widely-extended depofition,
A foft mafs of alluvial depofite, having its pores
filled with water, and being fubje& to the vi-
brations of a fuperincumbent fluid, will yield
to the preffure of that fluid on the fide of the
leaft refiftance, that is, on the fide toward the
fea, and thus will be gradually extended more
and more over the bottom. This will happen
not only to the finer parts of the detritus, but
even to the groffer, fuch as fand and gravel. For
fuppofe that a body of gravel refts on a plane
fomewhat inclined, at the fame time that it is
covered with water to a confiderable depth, that
water being fubje& not only to moderate re-
ciprocations, but alfo to fuch violent agitation
as we fee occafionally communicated to the wa-
ters of the ocean; the gravel, being rendered
lighter by its immerfion in the water, and on
that account more moveable, will, when the un-
dulations are confiderable, be alternately heaved
up and let down again. Now, at each time that
it is heaved up, however fmall the {pace may
be, it muft be fomewhat accelerated in its de-
{cent, and will hardly fettle on the fame point
where it refted before. Thus it will gain a lit-

tle

HUTTONIAN THEORY. 415

tle ground at each undulation, and will flowly
make its way towards the depths of the ocean,

or to the loweft fituation it can reach. ‘This, as

far as we may prefume to follow a progrefs which
is not the fubject of immediate obfervation, is
one of the great means by which loofe materials
of every kind are tranfported to a great dift
and fpread out in beds at the bottom of the
ocean.

369. The lighter parts are more eafily carried
to great diftances, being actually fufpended in the
water, by which they are very gradually and
flowly depofited. A remarkable proof of this is
furnifhed from an obfervation made by Lord
Mulgrave, in his voyage to the North Pole. In
the latitude of 65° nearly, and about 250 miles
diftant from the neareft land, which was the
coaft of Norway, he founded with a line of 683
fathoms, or 4098 feet; and the lead, when it
ftruck the ground, funk in a foft blue clay to the
depth of 10 feet*, The tenuity and finenefs
of the mud, which allowed the lead to fink fo
deep into it, muft have refulted from a depofi-
tion of the lighter kinds of earth, which being
fufpended in the water, had been carried toa

ance,

great diftance, and were now without doubt

forming

* Phipps’s Voyage, p. 74, 141.

416 ILLUSTRATIONS OF THE

forming a regular ftratum at the bottom of the

fea, o<
370. The quantity of detritus brought down
by the rivers, and diftributed in this manner over
the bottom of the fea, is fo great, that feveral
narrow feas have been thereby rendered fenfi-
bly fhallower. The Baltic has been computed to
decreafe in depth at the rate of forty inches in a
hundred years. The Yellow Sea, which is a large
gulf contained between the coaft of China and the
peninfula of Corea, receives fo much mud from
the great rivers that run into it, that it takes its
colour, as well as its name, from that circum-
fiance; and the European mariners, who have
lately navigated it, obferved, that the mud was
drawn up by the fhips, fo as to be vifible in
their wake to a confiderable diftance *, Com-
putations have been made of the time that it
will require to fill up this gulf, and to with-
draw it entirely from the dominion of the ocean:
but the data are not fufficiently exact to afford
any precife refult, and are no doubt particular-
ly defective from this caufe, that much of the
earth carried into the gulf. by the rivers, muĝ
be carried out of it by the currents and tides,
and the finer parts wafted probably to great di-
flances

* Staunton’s Account of the Embafly to China, vol. i
P. 448.

HUTTONIAN THEORY: 419

fiancés in the Pacific Ocean*. The mere at-

tempt, however, towards fuch a computation,

fhews how evident the progrefs of filling up is
to every attentive obferver ; and, though it may
not afcertain the meafure, it fufficiently declares
the reality of the operations, by which the wafte
of the prefent continents is made fubfervient to
the formation of new land.

- 371. Sand-banks, fuch as abound in the Ger-
man Ocean, to whatever they owe their origin,
are certainly modified, and their form determi-
hed, by the tides and currents. Without the ope-
ration of thefe laft, banks of loofe fand and mud
could hardly preferve their form, and remain
interfected by many narrow channels. The for-
mation of the banks on the coaft of Holland,
and even of the Dogger Bank itfelf, has been
afcribed to the meeting of tides, by which a ftate
of tranquillity is produced in the waters, and of
confequence a more copious depofition of their
mud. Even the great bank of Newfoundland

feems to be determined in its extent by the

action

* Peroufe, in failing along the coaft of China, from
Formofa to the ftrait between Corea and Japan, though
generally fifty or fixty leagues from the land, had found.
ings at the depth of forty-five fathoms, and fometimes
at that of twenty-two. Atlas du Voyage de la Peroufe,
No, 43.

418 ILLUSTRATIONS OF THE

action of the gulf-ftream. In the North Sea,
the current which fets out of the Baltic, has evi-
dently determined the fhape of the fand-banks
oppofite to the coaft of Norway, and produced
a circular {weep in them, of which it is impofli-
ble to miftake the caufe.

In proof of the adion here afcribed to the
waters of the fea, in tranfporting materials to an
unlimited extent, we may add the well-known
obfervation, that the ftones brought up by the
lead from the bottom of the fea, are generally
round and polifhed, hardly ever fharp and an-
gular. This could never happen to ftones that
were not fubje& to perpetual attrition.

372. Currents are no doubt the great agents in
. diffufing the detritus of the land over the bottom
of the fea. ‘Thefe have been long known to ex-
ift; but it is only fince the later improvements
in navigation, that they have been underftood to
conftitute a fyftem of great permanence, regu-
larity and extent, connected with the trade-
winds, and ether circumftances in the natural
hiftory of the globe. The gulf-ftream was ma-
ny years fince obferved to tranfport the water,
and the temperature of the tropical regions into
the climates of the north; and we are indebted to
the refearches of Major RENNEL, for the know-
ledge ofa great fyftem of currents, of which it is
only a part. That geographer, who is fo eminent

for

a

aid as

HUTTIONIAN THEORY. 419

for enriching the details of his:fcience with the
moft interefting facts in hiftory or in phyfics, has
fhewn, that along the eaftern coaft of Africa,
from about the mouth of the Red Sea, a current
fifty leagues in breadth fets continually towards
the fouth-weft *. It doublesthe Cape of Good
Hope, runs from thence north-weft, preferving
on the whole the direction of the coatt, but
reaching fo far into the ocean, that, about the
parallel of St Helena, its breadth exceeds 1009
miles. From thence, as it approaches the line,
its direction is more nearly eaft , and meeting in
the parallel of 3° north, with a current which
has come along the weftern coaft of Africa from
the north, the two united ftretch acrofs the At-
lantic, in a line fomewhat fouth of weft, and in
a very wide and rapid ftream. This ftream
meets the American land at Cape St Roque,
where it is joined by another coming up along
the eaftern fhore of that continent, and direét-
ed towards the north. They proceed north-
ward together till they enter the Gulf of Flo-
rida, from which being as it were reflected, they
form the Gulf-ftream, pafling along the coaft
of North America, and ftretching acrofs the At-
lantic to the Britifh Ifles. From thence the cur-
rent turns to the fouth, and, proceeding down

Dea. | the

* Geography of Herodotus, p.672,

420 ILLUSTRATIONS OF THE

the coaft of Spain and Africa, meets the ftream
afcending from the fouth, as already defcribed,
and thus continues in perpetual circulation,
The velocity of thefe currents is not lefs remark-
able than their extent. At the Cape of Good
Hope, the rate is thirty nautical miles in twenty-
four hours ; in fome places forty-five; and un-
der the line feventy-feven. When the Gulf-ftream
iffues from the Straits of Bahama, it runs at the
rate of four miles an hour, and proceeds to the
diftance of 1800 miles, before its velocity is re-
duced to half that quantity. In the parallel of
38°, near 1000 miles from the above ftrait, the
water of the ftream has been found ten degrees
warmer than the air.

373. The courfe of the Gulf-ftream is fo fixed
and regular, that nuts and plants from the Weft
Indies are annually thrown afhore on the Weft-
ern Iflands of Scotland. The maft of a man
of war, burnt at Jamaica, was driven feveral
months afterwards on the Hebrides *, after per-
forming a voyage of more than 4000 miles, un-
der the direction of a current, which, in the
midft of the ocean, maintains its courfe as ftea-

dily as a river does upon the land.
The great fyftem of currents thus traced
through the Atlantic, has no doubt phenomena
correfponding

:* Pennant’s Arctic Zoology, Introd. p. 70:

rown ashore on tele

among the foffils of another.
™ volutions of the globe, the economy of nature
it" has been uniform, in this refpe&, as well as in
f fomany others, and her laws are the only thing

_ that have refifted the general movement. —

HUTTONIAN THEORY. 421
correfponding to it in the Indian and Pacific
Oceans, which the induftry of future navigators
may difcover. The whole appears to be con-
nected with the trade-winds, the figure of our
continents, the temperature of the feas them-
felves, and perhaps with fome inequalities in the
ftructure of the globe. The difturbance pro-
duced by thefe caufes in the equilibrium of the
fea, probably reaches to the very bottom of it,
and gives rife to thofe counter currents, which
have fometimes been difcovered at great depths
under the furface *.

The great tran{portation of materials that
muft refult from the action of thefe combi-
ned currents is obvious, and ferves not a little

_ to diminifh our wonder, at finding the produc-

jaod plants from lee

tions of one climate fo frequently included
Amid all the re-

The

rivers and the rocks, the feas and the continents,

have been changed in all their parts; but the
_ laws which dire& thofe changes, and.the rules

Dd 3 to

* Hiftoire Naturelle de Buffon, fupplément, tom. ix.
P 479. 8vo,

422 ILLUSTRATIONS OF THE

to which they are fubjé€t, have rémained inva-
riably the fame.

374. Objections have been made to that tranfla-
tion of materials by the waters of the ocean
which is fuppofed in this theory, particularly by
Mr Kirwan, in his Geological Effays; and, though —
I might perhaps content myfelf with the remark
already made, that-the Neptunian fyftem inə
volves fuppofitions concerning the tranfportation
of folid bodies by the fea, in the early ages of
the world, as wonderful as thofe which, accord-
ing to our theory, are common to all ages, I am
unwilling to remain fatisfied with a mere ar-
gumentum ad hominem, where the fallacy of the
reafoning is fo eafily detected.

375. One of Mr Kirwan’s objections to the dé-
pofition of materials at the bottom of the fea, is
thus fated: “ Frist has remarked, in his ma-
thematical difcourfes, that if any confiderable
mafs of matter were accumulateéd in the interior
of the ocean, the diurnal motion of the globe
would be difturbed, and confequently it would
be perceptible; a phenomenon, however, of
which no hiftory or tradition gives any ac-
count *.”’

The. appeal made here to Frifi is fingularly
unfortunate, as that philofopher has demonftra-

ted

* Geol. Effays, p. 441.

HUTTONIAN THEORY. 423

ted the very contrary of Mr Kirwan’s pofi-
tion, and has proved, that the difturbance gi-
yen to the diurnal motion by the caufes here
referred to may be real, but cannot be percepti-
ble. Having inveftigated a formula exprefling
the law which all fuch difturbances muft ne-
ceflarily obferve, he concludes, “ Hac autem
formula manifeftum fiet, ex iis omnibus varia-
tionibus que in terreftri fuperficie obfervari fo-
lent, montium et collium abrafione, dilapfu cor-
porum ponderofiorum in inferiores telluris finus,
nullam oriri poffe variationem /enfibilem diurni
motûs. Nam fi ftatuamus data aliqua annorum
periodo terreftrem fuperficiem ad duos ufque
pedes abradi undique, eam vero materiæ quan-
titatem ad profunditatem pedum roco dilabi ;
erit omne quod inde orietur incrementum velo-
$5090 a I MET
(19638051)* ~ 12855068184 `

Here, it is evident, that Frifi admits thofe
very changes on the furface which we are con-
tending for, and fhews, that their tendency is to
accelerate the earth’s diurnal motion, but, by a
quantity fo fmall, that, in a fpace of time amount-
ing at leaft to 200 years, the increafe of the diur-
nal motion would only be fuch a part of the
Dd4 whole

citatis diurni motis

* Frifi Opera, tom. ili, p. 269.

424 ILLUSTRATIONS OF THE

whole as the preceding fra&tion is of unis
ty *.

376. The

* The time requifite for taking away by wafte and
erofion two feet from the furface of all our continents,
and depofiting it at the bottom of the fea, cannot be rec-
koned lefs than 200 years. The fraction vsyrrosrron
reduced to parts of a day, is yz,-;_ of a fecond; fo
that it would require 200 years to fhorten the length of
the day, by the above fraction of a fecond; and there-
fore it would require 148554 times 200 years, or
29710800 years, to diminifh it an entire fecond. The
accumulated effect, however, of all the diminutions du-
ring that period, would amount to much more: and if
we had any perfectly uniform ftandard to compare the
motion of the earth with, its difference from that ftand-
ard would increafe as the fquares of the time, and the
total acceleration would amount to one fecond in
“4080 years. Whatever relation this bears to the
age of the globe itfelf, it exceeds more than ten times
the age of any hiftorical record.

Though Frifius concludes, as is ftated here, that the
acceleration produced in the diurnal motion of the
earth, is far too inconfiderable to become the objet of
aftronomical obfervation, he makes a fuppofition diffi-
cult to be reconciled with this conclufion. namely, that
the acceleration has had a fenfible effect on the figure of
the earth, or rather of the fea, having increafed the cen-
: trifugal force, and thereby accumulated the waters un-
der the equator, in the prefent, more than in former
ages. Such an accumulation, he thinks agreeable to

certain

HUTTONIAN THEORY. 425

376. The inftance juft given may ferve as one of
many, to fhew what confidence is to be placed
jn that indigefted mafs of facts and quotations
which Mr Kirwan, without difcrimination, and
without difcuffion, has brought together from
all quarters. He has no intention, I believe, to
deceive his readers; but we may judge, from
this fpecimen, of the precautions he has taken
againft beins `. ceived himfelf.

In fome refpects, the refult of Frifi’s invefti-
gation muft be confidered as imperfect. If there
were no relative motion in the parts of our globe,
but that by which things defcend from a high-
er toa lower level, a continual acceleration of
its rotation, though extremely flow, would take
place, as above computed. But as, in the in-

terior of the earth, there are undoubtedly mo-

tions of a tendency oppofite to thofe on the fur-
face, and directed from the centre towards the

circumference,

certain appearances that have been obferved ref{pecting
the ancient level of the fea. Thefe appearances will
be afterwards confidered : it is fufficient to remark here,
that though the fraction, exprefling the increment of the
centrifugal force, muft be double that which expreffes

the acceleration, it muft be too fmall to have any per-
ceptible effect in elevating the fea, except after an im-

- menfe interval of time; and the compenfations which

arife from other caufes, probably muft prevent it from
becoming fenfible in any length of time whatfoever,

426 ILLUSTRATIONS OF THE

circumference, they muft produce a retardation
in the diurnal revolution; and from this muft
arife an inequality, not uniformly progreffive in
the fame direction, but periodical, and confined
within certain limits, as the caufes are by which
it is produced *.

377. Mr

* Even in the defcent of bodies from a higher to a
lower level at the furface of the earth, the whole ten-
dency is not to increafe the velocity of the earths rota-
tion, and many compenfations take place, which, when
the matter is confidered only in general, are neceflarily
overlooked. This will appear evident, if we refled;
that it is not fimply the approach of a body towards the
centre of the earth, or its removal from that centre,
which tends to difturb the rotation of the earth; but its
approach to the axis of the earth, or its removal from
that axis. The velocity with which a particle of mat-
ter revolves, whether on the furface, or in the interior
ef the globe, is proportional to its diftance from the
axis of rotation; 'and therefore, when a body comes
nearer to the axis, it lofes a part of the motion which it
had before; which part, of confequence, is communica-
ted to the whole mafs of the earth, and therefore tends
to increafe the velocity with which it revolves, ‘The
contrary happens when a body recedes from the axis;
for it then receives an addition to its velocity, which,
of courfe, is taken away from the rotatory motion of the
earth.

Hence, bodies moving in a horizontal plane, may in-
creafe or diminifh the fwiftnefs of the diurnal motion;

according

HUTTONIAN THEORY. 427

377. Mr Kirwan’s fecond objection is founded
pn the mifapprehenfion of a well-known fact in
the

according as they move towards the poles or towards the

equator; and thofe which defcend from a higher toa
lower level, difturb the earth’s rotation, much more in
confequence of their horizontal, than of their perpendi-
cular motion. The Ganges, for inftance, though its
fource is probably elevated no lefs than 7000 feet above
the level of the fea, tends to retard the earth’s rotation,
by bringing its waters, and the mud contained in them,
from the parallel of 31° to that of 22°, and fo increa-
fing their diftance from the earth’s axis by more than
yzth part. “Had the Ganges flowed towards the north,
as the Nile does, its effect would have been juft the con.
trary.

In the fame manner, a ftone defcending from the top
of a mountain, may accelerate or retard the earth’s rota-
tion, according to the direCtion in which it defcends. If
it defcend on the fide of the elevated pole, it will then
produce acceleration, becaufe its diftance from the axis
will be diminifhed ; but if it defcend on the fide of the
feprefled pole, and if the diretion in which it is mo-
ved, be over a line lefs inclined, than a line drawn from
the fame point to the deprefled pole, it will then pro-
duce a retardation, becaufe its diftance from the axis
will be increafed.

Let us fuppofe, for example, that the top of Mount

` Blanc is in latitude 45° 49%, and that its height is 2450

toifes above the level of the fea. The point at which
@ line drawn from the top of this mountain, parallel to
the

428 ILLUSTRATIONS OF THE

the natural hiftory of the earth. “ Rivers,” fays
this author, “ do not carry into the fea the fpoils
which they bring from the land, but employ them
in the formation of deltas of low alluvial land at
their mouths, according to what Major Rennell
has proved.” The fat of the formation of del.
tas from the fpoils which the rivers carry from

the

the earth’s axis, will meet the fuperficies of the fea,
(fuppofing that fuperficies continued inland from the
Mediterranean), muft be about 2382 toifes in horizontal
diftance, or about 24 minutes fouth of the fummit} that
is, in the parallel of 45° 46%’; and if this parallel be
continued all round the globe, the points of the earth’s
furface between it and the equator, are all more diftant
from the earth’s axis than the top of Mount Blanc is;
whereas all the points to the north of it are nearer to
that axis. A ftone, therefore, from the top of Mount
Blanc, if carried any where to the fouth of the above
parallel, will retard the earth’s diurnal motion; but if
carried any where to the north of the fame line, will ac-
celerate that motion. ?

The fame quantity of matter, however, carried an
equal diffance toward the pole, and toward the equator,
from any point, will lofe more velocity in the former
cafe than it will gain in the latter, as eafily follows
from the nature of circle. ‘Therefore, fuppofing an
équal difperfion of the detritus of a mountain in all di-
rections, the parts that go toward the pole will moft di-
{turb the diurnal motion; and hence a balance on their
fide, or in favour of acceleration, as already obferved.

ea, aia
i the tp of Mork)

of it we ap

HUTTONIAN THEORY. 429

the higher grounds, is perfectly afcertained ; and
the detail into which Major Rennel has entered
in the paffage referred to by Mr Kirwan, does
credit to the acutenefs and accuracy of that ex-

cellent geographer. But it is not there afferted,
that rivers employ all the materials which they
carry with them, in the formation of thofe del-
tas, and deliver none of them into the fea. On
the contrary, they carry from the delta itfelf
mud and earth, which they can depofite nowhere
but in the fea; and it is this circumftance
chiefly that limits the increafe of thofe alluvial
lands, and makes them either ceafe to increafe,
or makes them increafe very flowly after a cer-
tain period, though the fupply of earth from
the higher grounds remains nearly the fame.
To make Mr Kirwan’s argument conclufive, it
would be neceflary to prove, that aX the mud
carried down by the Nile or the Ganges, was
depofited on the low lands before thefe rivers
enter the fea; a thing fo obvioufly abfurd, that
nothing but his hafte to obtain a conclufion un-
favourable to the Plutonic fyftem, could have
prevented him from perceiving it *.

378. A

* The inftance mentioned in the Geological Effays,
from the travels of the Abbé Fortis, concerning urns
thrown into the Adriatic, upwards of 1400 years ago,

and

430 ILLUSTRATIONS OF THE

378. A remark which Major Rennell has made
concerning the mouths of rivers, in his Geogra-
phy of Herodotus, deferves Mr Kirwan’s atten-
tion, though perhaps he may not be able to put
on it an interpretation quite fo favourable to his
fyftem. The remark is, that the mouths of
great rivers are often formed on principles quite
oppofite to one another, fo that fome of them
have a real delta or triangle of flat land at their
mouths, while others have an eftuary, or what
may, not improperly be called a negative delta.
Of the latter kind are fome of the greateft rivers
in the world, the Plata, the Oroonoko and the
Maranon, and by far the greateft number of our
European rivers. Nobody can doubt, that the
three rivers juft named carry with them as much
earth as the Nile, or the Euphrates, or any other
river in the world. All this they have depofi-
ted in the fea, and committed to the currents,
which {weep along the fhore of the American
continent, and by thefe they have been fpread
out over the unlimited tracts of the ocean.

Indeed,

and not yet covered with mud, muft be explained from
peculiar circumftances, or local caufes, with which we
are unacquainted, as it makes againft the depofition of
earth near the fhore, and in narrow feas; a general fact,

which, I think, every body admits.

ore of the ol
p Bore of the
ia bees
Asoftieor |
mise f

HUTTONIAN THEORY. 431

Indeed, nothing can be more juft than Dr
Hutton’s obfervation, that where low land is
formed at the mouths of rivers, there the rivers
bring down more than the fea is able to carry
away; but that where fuch land is not formed,
it is becaufe the fea is able to carry off imme-
diately all the depofite which it receives.

379. Mr Kirwan has denied on another princi-
ple the power of the fea to carry to adiftance the
materials delivered into it: “ Notwithftanding,”’
fays he, “ many particles of earth are by rivers.
conducted to, the fea, yet none are conveyed to
any difiance, but are either depofited at their
mouths, or rejected by currents or by tides;
and the reafon is, becaufe the tide of flood is
always more impetuous and forcible than the
tide of ebb, the advancing waves being prefled
forward by the countlefs number behind them,

whereas the retreating are prefled backward by
afar {maller number, as muft be evident to an
attentive fpectator ; and hence it is that all float-

ing things caft into the fea, are at laft thrown
on fhore, and not.conveyed into the mid regions
of the fea, as they fhould be if the reciprocal
undulations of the tides were equally power-
ful *.”?

380. But

* Kirwan’s Geol. Effays, P- 439-

432 ILLUSTRATIONS OF THE

380. But if the attentive fpectator, inftead of
trufting to a vague impreflion, or liftening to
fome crude theory of undulations, refle&s on
one of the moft fimple facts refpecting the ebb-
ing and flowing of the tides, he will be very
little difpofed to acquiefce in the above conclu-
fion. He has only to confider, that the flowing
of the tide requires juft fix hours, and the ebb-
ing of it likewife fix hours; fo that the fame
body of water flows in upon the fhore, and re.
treats from it, in the fame time. The quantity
of matter moved, therefore, and the velocity
with which it is moved, are in both cafes the
fame; and it remains for Mr Kirwan to thew
in what the difference of their force can pofli-
bly confift.

The force with which the waves ufal break
upon our fhores, does not arife from the velo-
city of the tide being greater in one direction
than in another. In the main ocean, the waves
have no progreflive motion, and the columns of
water alternately rife and fall, without any other
than a reciprocating motion: a kind of equilibri-
um takes place among the undulations, and each
wave being equally acted upon by thofe on op-
pofite fides, remains fixed in its place. Near
the fhore this cannot happen; the water on the —
land fide from its fhallownefs being incapable

of

ofall, without!
is:
be pla

HUTTONIAN THEORY. 433

of rifing to the height neceffary to balance the
great undulations which are without. The wa-

ter runs, therefore, as it were, from a higher to

a lower level, fpreading itfelf towards the land
fide. ‘This produces the breakers on our fhores,
and the furf of the tropical feas. A rock ora

fand-bank coming within a certain diftance of

the furface, is fufficient, in any part of the ocean,
to obftruct the natural fucceflion of undulations ;
and, by deftroying the mutual reaction of the
waves, to give them a progreflive inftead of a
reciprocating motion.

381. It is, however, but from a {mall diftance,
that the waves are impelled againft the fhore
with a progreflive motion. The border of break-

F ers that furrounds any coaft is narrow, compa-
F xed with the diftance to which the detritus from

the land is confeffedly carried ; the water, while
it advances at the furface, flows back at the bot-

tom; and thefe contrary motions are fo nearly

equal, that it is but a very momentary accumu-
lation of the water that is ever produced on any
fhore.

If it were otherwife, and if it were true that
the fea throws out every thing, and carries away

nothing, we fhould have a conftant accumula-

tion of earth and fand along all fhores whatfo-
ever, at leaft wherever a ftream ran into the fea.
Ee This,

434 ILLUSTRATIONS OF THE

This, as is abundantly evident, is quite contra-
ry to the fad.

So, alfo, the bars formed at the mouths of ri-
vers, after having attained a certain magnitude,
increafe no farther, not becaufe they ceafe to
receive augmentations from the land, but be-
caufe their diminution from the fea, increafing
with their magnitude, becomes at length fo
great, as completely to balance thofe augmen-
tations. When properly examined, therefore,
the phenomena, which have been propofed as
moft inconfiftent with the indefinite tran{porta-
tion of ftony bodies, afford very fatisfactory
proofs of that operation.

382. It is true, that bodies which float in the wa-
ter, when carried along on the tops of the waves
towards a fhelving beach, having acquired a cer-
tain velocity, are thrown farther in upon the land
than the diftance they would have floated to, if
they had been fimply fuftained by the water.
The depth of water, therefore, at the place
where they take the ground, is not likely to be
fuch as to float them again, and to carry them
out towards the fea. They are, therefore, left
behind; and this produces an appearance of a
- force impelling floating bodies towards the land,

much greater and more general than really takes
place. 7

Thefg

would pro
tom did n

The fać
vigation v
had very {

| that they

But from
hitly ded

| tom of th

but little

Dut even

tlon from

lead broy

Siege

š SA ;

HUTTONIAN THEORY. 435

Thefe obfervations may ferve to fhow, how
unfound the principles are from which Mr Kir-
wan’s conclufions are deduced: they are per-
haps more than is neceflary for that purpofe : it
might have been fufficient to obferve, that the in-
creafe of land on the fea-fhore is limited, though
the augmentation from the land is certainly in-
definite, a proof that the diminution from the
fea is conftant and equal to the increafe.

383. “Mariners,” fays Mr Kirwan, “ were accu-
ftomed, for fome centuries back, to difcover their
fituation, by the kind of earth or fand brought
up by their founding plummets ; a method which
would prove fallacious, if.the furface of the bot-
tom did not continue invariably the fame *.”’

The fact here ftated, that mariners, when na-
vigation was more imperfect than it is now,
had very frequent recourfe to this method, and
that they ftill ufe it occafionally, is very true.
But from this, the only inference that can be
fairly deduced is, that the changes at the bot-
tom of the fea are very flow, and the variation
but little; not merely from one year to another,
but even from one century to another. The
rules by which the mariner judged of his pofi-
tion from the quality of the earth which the
lead brought up, and which were deduced no

Ecs doubt

* Geol. Effays, p. 440.

430 ILLUSTRATIONS OF THE

doubt from obfervations made at no very great
diftance of time, might be fufficient for his pur-
pole, though a flow change had been all the
while going forward. Such obfervations could

at beft have little accuracy, and could not be `

affected by {mall variations. Itis the flownefs of
the change, that makes the experience of one
age applicable, in this, as in innumerable other
inftances, to the obfervations of the next. Ifa
long interval is taken, we will look in vain for
the fame uniformity of refults. A pilot, who
would at prefent judge of his pofition in the
German Ocean, by comparing his foundings with
thofe taken by Pyrueas, (f{uppofing them known)

in his navigation of that fea, more than 2000 |

years ago, could hardly be expected to deter-
mine his latitude and longitude with great ex-
acinefs; and I know not if the moft zealous
advocate for the immutability of the earth’s
furface, would be willing to truft his fafety in
a fhip that was guided by fuch antiquated
rules. ‘

Nore

Es

qn

ios, W
“gence
fers t
apra
je pel
‘pe prii

- emati
- tations
“te con
1 faltei

dits of

pot if the mot wy

gutability of the
to rule his

cd by fuch w

Di

a

a

wo

HUTTONIAN THEORY. 4

Note xx. § 118.
Inequalities in the Planetary Motions.

334. The affertion that, in the planetary mo-
tions, we difcover no mark, either of the com-
mencement or termination of the prefent order,
refers to the late difcoveries of La Grancz and

~ La Prace, which have contributed fo much to

the perfection of phyfical aftronomy. From

the principle of univerfal gravitation, thefe ma-

thematicians have demonftrated, that all the va-
riations in our fyftem are periodical ,; that they
are confined within certain limits; and confift
of alternate diminution and increafe. The or-
bits of the planets change not only their po-
fition, but even their magnitude and their form :
the longer axis of each has a flow angular mo-
tion; nd, though its length remains fixed, the
fhorter axis increafes and diminifhes, fo that the
form of the orbit approaches to that of a circle,
and recedes from it by turns. Inthe fame man-
ner, the obliquity of the ecliptic, and the incli-
Nation of the planetary orbits, are fubject to
change ; but the changes are fmall, and, being
firft in one direction, and then in the oppofite,

Eeg

F
they

438 ILLUSTRATIONS OF THE

they can never accumulate fo as to produce a per-
manent or a progreffive alteration. Thus, in the
celeftial motions, no room is left for the introduc-
tion of diforder ; no irregularity or difturbance,
arifing from the mutual action of the planets, is
permitted to increafe beyond certain limits, but
each of them, in time, affords a correction for it-
felf. The general order is conftant, in the midft
of the variation of the parts; and, in the lan-
guage of La Place, there is a certain mean con-
dition, about which our fyftem perpetually o/c7/-
lates, performing {mall vibrations on each fide
of it, and never receding from it far*. The
fyftem is thus endowed with a ftability, which
can refift the lapfe of unlimited duration; it
can only perifh by an external caufe, and by the
introduction of laws, of which at prefent no vef-
tige is to be traced.

385. The fame calculus to which we are indebt-
ed for thefe fublime conclufions, informs us of
two circumftances, which mark the law here
treated of as an effect of wife defign, to thé entire
exclufion both of neceflity and chance. One of
thefe circumftances confifts in the planetary
motions being all in the fame direction, or all
in confequentia, as it is called by the aftrono-

| mers.

* Expofition du Syftéme du Monde, par La Place,
Livre iv. chap. 6. p. 199. 2d edit.

cul

that 1

is th)
soils P girl d
A by wi
; wi
y”

i Ga

HUTTONIAN THEORY. 439

mers. This is effential to the compenfation and
ftability above mentioned * : had one planet
circulated round the fun in a direction from eaft
to weft, and another in a direction from weft
to eaft, the difturbances they would have produ-
ced on one another’s motion would not necet-
farily have been periodical ; their irregularities
might have continually increaled, and they
might have deviated in the courfe of ages from
their original condition, beyond any limits that.
can be affigned. |

The other circumftance, on which the ftability
of our fyftem depends, is the fmall eccentricity
of the planetary orbits, or their near approach
to circles. Were their orbits very eccentric, an

opening would be given to progreflive change,

that might fo far increafe, as to prove the de-
ftruction of the whole. But neither the move-
ment of all the planets in the fame direction, nor
the {mall eccentricity of their orbits, can be
afcribed to accident, fince that either of thefe
fhould happen by chance, in as many inftances
as there are planets, both primary and fecondary,
is almoft infinitely improbable. Again, that
any neceflity in the nature of things fhould have
either determined the direction of the planetary

` motions, or proportioned the quantity of them

Beg to

* La Place, zdid.

440 ILLUSTRATIONS OF THE

to the intenfity of the central force, cannot be
admitted, as thefe are things unavoidably concei-
ved to be quite independent of one another. It
remains, therefore, that we confider the laws,
which make the difturbances in our fyftem cor-
rect themfelves, and by that means give firm-
nefs and permanence to it, as a proof of the con-
fummate wifdom with which the whole is con-
ftructed.

386. The geological fyftem of Dr Hutton, re-

fembles, in many refpects, that which appears to
prefide over the heavenly motions. In both, we

perceive continual viciffitude and change, but
confined within certain limits, and never depart-

ing far from a certain mean condition, which -

is fuch, that, in the lapfe of time, the deviations
from it on the one fide, muft become juft equal
to the deviations from it on the other. In both,
a provifion is made for duration of unlimited

extent, and the lapfe of time has no effet to

wear out or deftroy a machine, conftru@ed with
fo much wifdom. Where the movements are
all fo perfect, their beginning and end muft be
alike invifible.

Nore

HUTTONIAN THEORY. 44t

Norte xx; § 122.
Changes in the apparent Level of the Sea.

387. In {peaking of the natural epochas mark-
ed out by the phenomena of the mineral king-
dom, we have fuppofed a greater fimplicity, and
feparation of effects from one another, than pro-
bably takes place in nature. We have, for in-
ftance, abftracted, in {peaking of the wafte and
degradation of the land, from that elevation
which may have been carried on at the fame
time. This appeared neceflary to be done, in
order to fimplify as much as poflible the view
that was to be given of the whole; but there
can be no doubt, that, while the land has
been gradually worn down by the operations
on its furface, it has been raifed up by the ex-
panfive forces acting from below. There is
even reafon to think, that the elevation has not
been uniform, but has been fubject to a kind
of ofcillation, infomuch, that the continents have
both afcended and defcended, or have had their
level alternately raifed and deprefled, inde-
_ pendently of all action at the furface, and this

| : within

442 ILLUSTRATIONS OF THE

within a period comparativel¥ of no great ex-
tent.

It will be eafily underftood, that the fads we
are going to ftate, each taken fingly, prove no-
thing more than a change of the line in which
the furface of the fea interfects the furface of
the land, leaving it uncertain to which of the
two the change ought really to be afcribed. Ta-
ken in combination, however, thefe fas may
determine what each of them feparately cannot
afcertain. I fhall firft, therefore, mention fome
of the principal obfervations relative to the
change above mentioned, and fhall then com-
pare them, in order to difcover whether it is moft
probable that this change has been produced by
the motion of the land or of the fea.

388. If we begin with examining the coafts of
our own ifland, we fhall find clear evidence every
where, that the fea once reached higher up up-
on the land than it does at prefent. The marks
of an ancient fea-beach are to be feen beyond the
prefent limits of the tide, and beds of fea-fhells,
not mineralized, are found in the loofe earth or
foil, fometimes as high as thirty feet above the
prefent level of the fea. Some of thefe on the
fhores of the Frith of Forth are very well
known, and have been often mentioned. Fn-
deed, on the fhores of that frith, many monu-
ments appear, which would feem to carry the

difference |

HUTTONIAN THEORY. 443

difference between the prefent and the ancient
level of the fea, to more than forty feet. The

É ground on:which the Botanic Garden of Edin-

burgh is fituated, after a thin covering of foil
is removed, confifts entirely of fea-fand, very
regularly ftratified, with layers of a black car-
bonaceous matter, in thin lamellz, interpofed
between them. Shells I believe are but rarely
found in it, but it has every other appearance of
a fea-beach. The height of this ground above
the prefent level of the fea is certainly not lefs
than 40 feet. z

389. Onalmoft every part of the coaft where the
= rocks do not rife quite abrupt and precipitous
_ from the fea, fimilar marks of the lowering of
the fea, or the rifing of the land, may be obfer-
ved. On the fhores oppofite to ours, the fame
appearances are remarked. The author of the
Lettre Critique to M. de Buffon, tells us, that

, i _ he had found the bottom of a bafon at Dunkirk,

which he had reafon to think was dug about
950 years ago, ten feet and a half above the
prefent low-water mark, though it muft have
been originally under it. The bottom of this
bafon is in the native chalk. From this, the
fame author concludes, that the fea at Dunkirk
lowers its level at the rate of an inch nearly m
feven years. The obfervation was made in
| 1702,

444 ILLUSTRATIONS OF THE

1762, (Lettre a M. le Comte de Buffon, &c:
pr) feo

390. The fhores of the Low Countries, and of
Holland, have been often inftanced in proof of
the fame kind of changes, and it has been fup-
pofed, that, independently of thofe artificial bar-
riers which at prefent exclude the waters of
the ocean from overflowing a great part of
this tract, nature herfelf has brought it near-
er to the furface than it had formerly been. It
is indeed certain, that thofe countries, to a ve-

ry great extent inland, have either been un-

der the fea at fome period, by no means re-
mote if compared with the great revolutions
of the globe, or that they are entirely alluvial,
and of the fame fort with the Deltas formed at
the mouths of rivers. The relative changes,
however, of the fea and land on this tract, have
been differently reprefented, and I am unwilling,

on

* In the county of Suffolk, near Wood Bridge, at the
diftance of feven or eight miles from the fea, are the
Crag-pits, in which prodigious quantities of fea-fhells
are difcovered, many of them perfe& and quite folid,
(Pennant’s Aréctic Zoology, Introd. p. 6.). Lincoln-
fhire affords various proofs of the fame kind; but fome
other circumftances in the appearance of that coaft, juft
about to be taken notice of, indicate changes of a more

complicated nature.

d graver

HUTTONIAN THEORY. 445

on that account, to found any argument on
them.

391. If we proceed farther to the north, tothe
fhores of the Baltic for inftance, we have un-
doubted evidence of a change of level in the
fame direction as on our own fhores. The le-
vel of this fea has been reprefented as lowering
at fo great a rate as 4o inches in a century.
Celfius obferved, that feveral rocks which are
now above water, were not long ago funken
rocks, and dangerous to navigators ; and he par-

ticularly took notice of one, which, in the year

1680, was on the furface of the water, and in

—) the year 1731 was 204 Swedith inches above it.

From an infcription near Afpô, in the lake Me-
lar, which communicates with the Baltic, en-
graved, as is fuppofed, about five centuries ago,
the level of the fea appears to have funk in that
time no lefs than 13 Swedifh feet *. All thefe
facts, with many more which it is unneceflary
to enumerate, make the gradual depreffion, not
only of the Baltic, but of the whole northern

ocean, a matter of certainty.

392. Suppoting thefe changes of level between
the fea and land to be {ufficiently aicertained, the
fuppofition which at firft occurs is, that the mo-

tion

* Friii Opera, tom. ili. p. 274.

446 ILLUSTRATIONS OF THE

tion has been in the fea rather than in the land,
and that the former has actually defcended to a
lower level. The imagination naturally feels
lefs difficulty in conceiving, that an unftable
fluid like the fea, which changes its level twice
every day, has undergone a permanent depref-
fion in its furface, than that the land, the terra
firma itfelf, has admi‘ted of an equal elevation.
in all this, however, we are guided much more
by fancy than reafon; for, in order to deprefs
or elevate the abfolute level of the fea, by a gi-
ven quantity, in any one place, we muft deprefs
or elevate it by the fame quantity over the
whole furface of the earth; whereas no fuch
neceflity exifts with refpe& to the elevation or
depreffion of the land. To make the fea fubfide
30 feet all round the coaft of Great Britain, it
is neceflary to difplace a body of water 30 feet
deep over the whole furface of the ocean. The
quantity of matter to be moved in that way is
incomparably greater than if the land itfelf were
to be elevated; for though it is nearly three
times lefs in fpecific gravity, it is as much great-

er in bulk, as the furface of the ocean is greater —
than that of this ifland.

393. Befides, the fea cannot change its level,
without a proportional change in the folid bottom
on which it refts. Though there be reafon to fup-

pofe

alt of Great Bash
a body of wate pth

fice of the oct |

EIIE

HUTTONIAN THEORY. 447

pofe that fuch changes in the bottom do adual-
ly take place, yet they are probably much flower
and more imperceptible than thofe which we
are here confidering. It is evident, therefore,
that the fimpleft hypothefis for explaining thofe
changes of level, is, that they proceed from the
motion, upwards or downwards, of the land it-
felf, and not from that of the fea. As no ele-
vation or depreflion of the fea can take place,
but over the whole, its level cannot be affected
by local caufes, and is probably as little fubje@
to variation as any thing to be met with on the

f furface of the globe.

394. Other dobfervations, however, made on dif-
ferent fhores from the preceding, give greater
certainty to this conclufion, and make it clear,
that the motion or change which we are now
treating of is not to be afcribed to the fea itfelf.

The obfervations juft mentioned prove, that
the level of the North Sea is lower now than it
was heretofore ; but it appears, that in the Me-
diterranean, the oppofite takes place. Very ac-
curate obfervations made by ManFrepI, render
it certain, that the fuperficies of the Hadriatic
was higher about the middle of the laft century,
than toward the beginning of the Chriftian æra.

Some repairs that were carrying on in the ca-
thedral church of Ravenna, in the year 1731,

afforded

448 ILLUSTRATIONS OF THE

afforded him an opportunity of obferving, that
the ancient, and probably original, pavement,
was four feet and a half below the prefent, and
nearly a foot under the level of the fea at high
water *. Now, when the church was built,
this cannot have been the pofition of the pave-
ment, relatively to the level of the fea, for it
would have fubje@ted the floor to be under wa-
ter twice in twenty-four hours, and muft have
done fo the more unavoidably, becaufe at that
time (the beginning of the 5th century) the
walls of Ravenna were wafhed by the fea. The
fact that this pavement is under the high-water
mark, by the quantity juit mentioned, was afcer-
tained by actual levelling. This refult was con-
firmed by fimilar faéts, obferved by LENDRINŞ
at Venice. |
395- Manfredi himfelf attributes all this to the
elevation of the furface of the fea, and has enter-
ed into a long calculation to afcertain at what
rate that furface may be fuppofed to rife, on ac-
count of the earth and fand brought down by
the rivers, and fpread out over the bottom of
the fea. But as the fad of the rife of the level
of

* Commentarii Academie Bononienfis, tom. ii.
ars ima, D. 2 &c. and pars 2da, p. 1. &c-
? ? ?

ibfide

HUTTONIAN THEORY. 449

of the fea is not general, and as the contrary is
obferved in the north feas, as already proved,

| this hypothefis will not explain the apparent rife

in the level of the Hadriatic.
396. Though a local fubfidence, or fettling of
the ground, could hardly account for this change,

_ the pavement being perfect in its level, and the

walls of the cathedral without any fhake, yet a

| fubfidence that has extended to a great tract, as

tothe whole of Italy, if the mafs moved has
continued parallel to itfelf, and changed its place

flowly, will agree very well with the appearances. _
The facts here ftated are alfo the more defer-
ving of attention, that about Ravenna, the land,

"| atthe fame time that it has funk in its level,
"| has extended its furface, and has encroached on
H the fea. Since the time of Aucustus, the line of
iti) the coaft has been carried farther out by about
i i three miles *.

This laft is the undoubted effect
of the degradation of the land by the rivers;
and here we have very clear evidence of the
forces, both under and above the furface, pro-
ducing their refpective effects at the fame time,
fo that while the furface is raifed by earth
brought down by the rivers, every given point in
Ff the

P ‘

* Manfredi, zbid:

450 ILLUSTRATIONS OF THE

the ground is depreffed and let down to a lower
level *.

397. On the fouthern coaft of Italy fimilar faĉts
have been obferved. BrerrsLAac, in his Topo-
grapbia Fifica della Campania di Roma +, from
certain appearances in the gulfs of Bajia and
Naples, concludes, that at the beginning of the
Chriftian æra, the level of the fea was lower on
that part of the coaft than it is now. The facts
which he mentions are the following: 1mo, The
remains of an ancient road are now to be feen
in the Gulf of Bajia at a confiderable diftance
from the land. 2do, Some ancient buildings be-
longing to Porto Julio are at prefent covered by

the fea. 3ti0, Ten columns of granite at the foot 7

of Monte Nuovo, which appear to have belong-
ed to the Temple of the Nymphs, are alfo near-
ly covered by the fea. 4to, The pavement of
the Temple of Serapis is now fomewhat lower
than the high-water mark, though it cannot be
fuppofed that this edifice when built was expo-

fed to the inconvenience of having its floor fre- —

quently under water. 50, The ruins ofa palace,
built

% On the coaft of Dalmatia alfo, the rifing of the le«
vel of the fea has been remarked, particularly at the —
ruins of Diocletian’s palace of Spalatro.

+ Cap. vi. p. 300-

r y m
a EN ai

Soe

Áa
J

HUTTONIAN THEORY. 451

built by Tiberius in the ifland of Caprea, are
now entirely covered by the fea.

Thus, it appears that the level of the fea is
finking in the more northern latitudes, and ri-
fing in the Mediterranean, and it is evident
that this cannot happen by the motion of the
fea itfelf. The parts of the ocean all com-
municating with one another, cannot rife in
one place and fall in another; but, in order to

maintain a level furface, muft rife equally or fall

equally over the whole of its extent. If, there-
fore, we place any confidence in the preceding

= obfervations, and they are certainly liable to no
objection, either from their own nature or the
character of the obfervers, we muft confider it

as demonftrated, that the relative change of le-
vel has proceeded from the elevation or depref-
fion of the land itfelf. This agrees well with
the preceding theory, which holds, that our

© continents are fubject to be acted upon by the

expanfive forces of the mineral regions; that
by thefe forces they have been actually raifed
up, and are fuftained by them in their prefent
fituation.

398. According to fome other facts ftated by
the fame ingenious author, it appears, that on
the coaft of Italy the progrefs of the fea in
afcending, or of the land in defcending, has not

Efso been

452 ILLUSTRATIONS OF THE '

been uniform during the period above mentioti-
ed, but that different ofcillations have taken
place; fo that, from about the beginning of the
Chriftian æra, till fome time in the middle ages,
the fea rofe to be fixteen feet higher than at pre-
fent, from which height it has defcended till it
= became lower than it is now, and from that ftate
_of depreffion it is now rifing again. Breiflac in-
fers this from two facts, which he combines ve-
ry ingenioufly with the preceding, viz. the re-
mains of fome ancient buildings, at the foot of
Monte Nuovo, five or fix feet above the prefent
level of the fea, in which are found the fhells of
fome of thofe little marine animals that eat into
ftone: And again, the marble columns of the
temple of Serapis, which are alfo perforated by

pholades, to the height of fixteen feet above

the ground. All thefe changes Breiflac afcribes
to the motion of the fea itfelf; a fuppofition
which, as we have feen, cannot poflibly be ad-
mitted, fince nothing can permanently affect the
level of the fea in one place, which does not af-
fect it in all places whatfoever.

399. Appearances, which indicate fuch alterna-
tions as have juft been mentioned in the level of
the fea, are to be met with on fome other coafts.
In England, on the coaft of Lincolnfhire, the re-

mains of a foreft have been oblerved, which are `

now

oa Yh, tf
eet a

Tiia

HUTTONIAN THEORY. 453

now entirely covered by the fea*. The fub-
marine ftratum which contains the remains of
this foreft, can be traced into the country to a

_ great diftance, and is found throughout all the

fens of Lincolnfhire. The ftratum itfelf is a-
bout four feet thick; it is covered in fome pla-
ces by a bed of clay fixteen feet thick, and un-
der it for twenty feet more is a bed of foft mud,
like the {courings of a ditch, mixed with fhells
and filt. l
Here then we have a ftratum which muft
have been once uppermoft on the furface of the
dry land, though one part of it is now immerfed
under the fea, and another covered with earth,
to the depth of fixteen feet. A change of level
in the fea itfelf will not explain thefe appearan-
ces: they can only be explained by fuppofing
the whole tract of land to have fubfided, which
is the hypothefis adopted by the author of the
defcription in the Tranfactions, M. Corria DE
SERRA; the fubfidence, however, is not here

_underftood to arife from the mere yielding of

fome of the ftrata immediately underneath, but
is conceived to be a part of that geological fy-
ftem of alternate depreffion and elevation of the
furface, which probably extends to the whole
mineral kingdom. ‘To reconcile all the differ-

<3 ent

* Phil, Tranf. 1799. p. 145.

454 ILLUSTRATIONS OF THE

ent facts, I fhould be tempted to think, that

the foret which once covered Lincolnfhire, was _

immerfed under the fea by the fubfidence of
the land to a great depth, and at a period con-
fiderably remote ; that when fo immerfed, it was
covered over with the bed of clay which now
lies on it, by depofition from the fea, and the
wafhing down of earth from the land; that it
has emerged from this great depth till a part of
it has became dry land; but that it is now fink-

ing again, if the tradition of the country de- “

ferves any credit, that the part of it in the fea
is deeper under water at prefent than it was a
few years ago. This might alfo ferve to recon-
cile, in fome meafure, the phenomena of this fub-
marine foret with the appearances which indi-
cate an extenfion of the land on the coaft of
Lincolnfhire. Indeed the extenfion of the land
is no dire&t proof, either of its own elevation, or
of the depreffion of the fea, as we may conclude
from the inftance of Ravenna already mention-
ed.

400. We have concluded from the facts {lated
above, that the level of the fea rifes in the
Mediterranean, and finks in the more northern
latitudes ; and thence fome have fufpected, that
the level of the fea had in general a tenden-
cy to rife towards the equator, and to fink to-

wards

b
i

|

’

HUTTONIAN THEORY. 455

wards the poles. This is the notion of Frifi, as
has been already remarked, and he fuggetts,
that this rife of the fea may be owing to a flight
acceleration in the earth’s diurnal motion. . But
there are facts which fhew, that between the tro-
pics the relative level of the fea and land has
funk, and is lower at prefent than it was at
fome former period, probably not extremely re-
mote. The opinion of Frifi, therefore, is un-
fupported by obfervation, and, as has been al-
ready fhewn, cannot be juftified from theory.
Between the tropics, iflands are formed from
the mere accumulation of coral; and it is the
peculiarity of thofe regions, to produce rocks that
have not pafled through the ufual procefs of
mineral confolidation *. The iflots, however,
which are thus formed, muft have their bafes
laid on a folid rock, though perhaps at a great
depth; and it is not probable, that after they

are once raifed above the furface of the fea,

they can ftill rife farther, except by fome eleva-
tion of the rock which ferves as their founda-
Ff4 tion.

* Dr Fofter, in his Voyage round the World, (vol. ii.
p.146.) gives an inftance in the South Sea Iflands, where
the furface of the ifland, though entirely a coral rock,
was raifed forty feet above the level of the fea,

456 ILLUSTRATIONS OF THE

tion*, Now, at Palmerfton ifland, which com-
prehends nine or ten low iflots, that may be
reckoned the heads of a great reef of coral
rock, Captain Cook informs us of his having
feen, “ far beyond the reach of the fea, e-
ven in the moft violent ftorms, elevated co-
ral rocks, which, on ination, appeared to
have been perforated in the fame manner that
the rocks are that now compofe the outer edge
of the reef. This evidently fhews,’’ he adds,
‘‘ that the fea had formerly reached fo far; and
{ome of thefe perforated rocks were almoft in
the centre of the ifland 4.2" ,

The fame excellent navigator, giving an ac-
count of the peninfula at Cape Denbigh, re-
marks: “ It appeared to me, that this peninfula

muf have been an ifland in remote times; for —

there were marks of the fea having flowed over
the ifthmus.”’ :

401. Weare here touching on one of thofe fub-
jects, where we feel much the want of accurate
and ancient obfervations, and where it is not from
the infancy, but the maturity of fcience that any
thing approaching to certainty can be looked
fore Lhe utmoft that we can expedt at prefent,

is

o * A very curious account of the formation of fuch

iflands is given by A. Dalrymple Efq; in the Philofo-

phical Tranfaétions, vol. lvii. p. 394. |
+ Cook’s Third Voyage, vol. i. p. 221.

HUTTONIAN THEORY. 457

js an anticipation, which future ages muft cer-
tainly modify, and corre. The beft thing,
in the mean time, that can be done for the
advancement of this branch of geological know-
ledge, is to afcertain with exactnefs the re-
lative level of the fea, and of fuch points upon
the land as can be diftinétly marked, and point-
ed out to fucceeding ages. ‘This is not fo eafy
as it may at firt appear. Where every obje&t
changes, it is difficult to find a meafure of
change, or a fixed point from which the compu-
tation may begin. The aftronomers already feel
this inconvenience, and when they would refer
their obfervations to an immoveable plane, that —
fhall preferve its pofition the fame in all ages,

_ they meet with difficulties, which cannot be re-
moved but by a profound mathematical invetfti-

gation. ,
In geology, we cannot hope to be delivered

_ from this embarraffment in the fame manner ;

and we have no refource but to multiply ob-
fervations of the difference of level; to make
them as exact as poflible, and to fele& points of
comparifon that have a chance of being long
diftinguifhed. The improvements in barome-
trical meafurements, which give fuch facility to
the determination of heights, along with fo con- —
fiderable a degree of accuracy, will furnifh an
accumulation of faéts that muft one day be of
great value to the geologift.

à NoTE

458 ILLUSTRATIONS OF THE

NOTE XXII. § 123.

Foffil Bones.

402. The remains of organifed bodies, at pre-
fent included: in the folid parts of the globe, may
be divided into three claffes. The firft confifts
of the fhells, corals, and even bodies of fih, and
amphibious animals, which are now converted
into ftone, and make integrant parts of the folid
rock. All thefe are parts of animals that exift-

ed before the formation of the prefent land, or .

even of the rocks whereof it confifts. Thefe re-
mains have been already treated of, and the evi-
dence which they furnifh muft ever be regarded
as of the utmoft importance in the theory of the

earth. The fecond clafs confifts of remains, —

which, by the help of ftalactitical concretions, are
converted into ftone. Thefe are the exuvie of
animals, which exifted on the very fame conti-
nents on which we now dwell, and are no doubt
the moft ancient among their inhabitants, of
which any monument is preferved. In compa-

rifon of the firft clafs, they muft, neverthelefs, be -

confidered as of very modern origin.

403. The third clafs confifts of the bones of
animals found in the loofe earth or foil; thefe
have not acqiiired a ftony character, and their na-

| ture

Thel

HUTTONIAN THEORY. 459

ture appears to be but little changed, except by the
progrefs of decompofition and of mouldering in-
to earth. No decided line can be drawn between
the antiquity of this and the preceding clafs, as
there may be between the preceding and the
firt. In fome inftances, the objects of this third
clafs may be coeval with thofe of the fecond ;
in general, they muft be accounted of later ori-
gin, as they are certainly not preferved ina man-
ner fo well fitted for long continuance.

404. The animal remains of the fecond clafs, are
generally found in the neighbourhood of lime-
ftone ftrata, and are either enveloped or penetra-
ted by calcareous, or fometimes ferruginous
matter. Of this fort are the bones found in the

! rock of Gibraltar, and on the coaft of Dalmatia.

The latter are peculiarly marked for their num-
ber, and the extent of the country over which they
are fcattered, leaving it doubtful whether they
are the work of fucceffive ages, or of fome fudden
eataftrophe that has affembled in one place, and
overwhelmed with immediate deftruction, a vaft

multitude of the inhabitants of the globe. Thefe

remains are found in greateft abundance in the
iflands of Cherfo and Ofero; and always in what
the Abbé Fortis calls an ocreo-ftalattitic earth.
The bones are often in the ftate of mere fplin-
ters, the broken and confufed relics of various
animals, concreted with fragments of marble

and

460 ILLUSTRATIONS OF THE

and lime, in clefts and chafms of the ftrata *,
Sometimes human bones are faid to be found in
thefe confufed maffes.

405. A very remarkable collection of bones in
this {tate is found in the caves of Bayreuth in Fran-
conia. Many of thefe belong, as is inferred with
great certainty from the ftruCture of their teeth,
to a carnivorous animal of vaft fize, and having
very little affinity to any of thofe that are now
known. The bones are found in different ftates,
{fome being without any ftalactitical concretion,
and having the calcareous earth ftill united to
the phofphoric acid, fo that they belong to the
third, rather than the fecond, of the preceding di-
vifions. In others, the phofphoric acid has wholly
difappeared, and given place to the carbonic.

The number of thefe bones, accumulated in ~

the fame place, is matter of aftonifhment, when
it is confidered, that the animals to which they
belonged were carnivorous, fo that more than
two can never have lived in the fame cavern at
the fame time. The caves of Bayreuth feem to

have been the den and the tomb of a whole dy-

nafty of unknown montfiers, that iffued from this
central fpot to devour the feebler inhabitants of
the woods, during a long fucceffion of ages, be-

. fore

* Travels into Dalmatia, P. 449.

the

ee,

E

HUTTONIAN THEORY. 46

fore man had fubdued the earth, and freed it
from all domination but his own.

406. The foffil bones of the fecond and third
clafs, but chiefly of the third, have now afford-
ed matter of conjecture and difcuffion for more
than a century. The facts with refpect to them
are very numerous and interefting, but can be
confidered here only very generally.

The remains of this kind, confift of the bones
only of large animals, fo that they have gene-
rally been compared with thofe of the elephant,

the rhinoceros, the hippopotamus, or other ani-

mals of great fize. The bones of {maller animals
have alfo been found, but much more rarely than
the other. It is ufually remarked, that the bones

_ thus difcovered in the earth are larger than thofe
of the fimilar living animals. |

Another general fact concerning thefe remains,

js, that they are found in all countries whatfo-
ever, but always in the loofe or travelled earth,
and never in the genuine ftrata.

Since the year
1696, when the attention of the curious was
called to this fubje&, by the fkeleton of an e-
lephant dug up in Thuringia, and defcribed
by Tentzelius*, there is hardly a country in
Europe which has not afforded inftances of
the

* Phil. Tranf. vol. xix. p. 757.

462 ILLUSTRATIONS OF THE

the fame kind. Foffil bones, particularly grind-
ers and tufks of elephants, have been found
in other places of Germany, in Póland, France,

Italy, Britain, Ireland, and even Iceland *. -

Two countries, however, afford them in greater
abundance by far than any other part of the
known world; namely, the plains of Siberia in
the old continent, and the flat grounds onthe
banks of the Ohio in the new +}. |

407. When the bones in Siberia were firft dif-
covered, they were fuppofed to belong to an ani-
mal that lived under ground, to which they gave
the name of the mammouth , and the credit be-
ftowed on this abfurd fiction, is a proof of the
ftrong defire which all men feel of reconciling ex-
traordinary appearances with the regular courfe
of nature. Much {kill, however, in natural hi-
ftory was not required to difcover that many of
the bones in queftion refembled thofe of the ele-
phant, particularly the grinders and the tuiks of
that animal. Others refembled the bones of the

rhinoceros; and a head of that kind, having the -

hide

* A grinder of an elephant found in Iceland, is de-
feribed by Bartholinus, Actor. Hafniens. vol. i. p. 383.

+ The foflil bones on the Ohio are defcribed in two
papers by Mr P. Collinfon, Phil. Tranf. vol. lvii. p. 404.
and 468.

a,

HUTTONIAN THEORY. 463

hide preferved upon it, was found in Siberia, and
is till in the imperial cabinet at Peterfburgh.

Pallas has defcribed the foffil bones which he
found in the mufeum at Peterfburgh, on his be-
ing appointed to the fuperintendence of it, and
enumerates, not only bones that belong, in his
opinion, to the elephant and rhinoceros, but
others that belong to a kind of buffalo, very dif-
ferent from any now known, and of a fize
vaftly greater *. He has alfo defcribed, in ano-
ther very curious memoir, the bones of the fame
kind that he met with in histravels through the
north-eaft parts of Afia.

The foffil bones found on the banks of the
Ohio, refemble in many things thofe of Siberia ;
like them they are contained in the foil or allu-
vial earth, and never in the folid ftrata; like
them too they are no otherwife changed from
their natural ftate, than by being fometimes
flightly calcined at the furface , they are alfo of

4 great fize, and in great numbers, being’ proba-

bly the remains of feveral different {pecies.

408. Two inquiries concerning thefe bones
have excited the curiofity of naturalifts ; firft, to
difcover among the living tribes at prefent inha-

biting

* Novi Comment. Petrop. tom. xiii. (1768) p. 436»
and tom. xvii. p. 576, &c.

464. ILLUSTRATIONS OF THE

biting the earth, thofe to which the foi res
mains may with the greateft probability be re-
ferred; and, fecondly, to find out the caufe
why thefe remains exift in fuch quantities, in
countries where the animals to which they be-
long, whatever they be, are at prefent unknown.
The folution of the firft of thefe queftions, is
much more within our reach than the fecond,
and at any rate muft be firft fought for.

On the authority of fo eminent a naturalift as
Pallas, the bones from Siberia may fafely be re-
ferred to the elephant, the rhinoceros, and buf-
falo, as mentioned above, though perhaps tova-
rieties of them with which we are not now ac-
quainted. With refpec to the bones of North
America, the queftion is more doubtful, for,they

have this particular circumftance attending them,

viz. that along with the thigh-bones, tufks, &c.
which might be fuppofed to belong to the ele-
phant, grinders are always found ofa ftruĉture and
form entirely different from the grinders of that a-
nimal *. Some naturalifts, particularly M. D’ Av-
BENTON, referred thefe grinders to the hippopota-
mus; but Dr W. Hunrer appears to have proved,
in a very fatisfactory manner, that they cannot
have

* See Mr Collinfon’s papers. above referred to, Phil.
Tranf, vol. lvii.

tuk

thigh bones,
J to belong to ted
fundatam”

othe snders tt

yD

alae an

HUTTONIAN THEORY. 465
have belonged to either of the animals juft men-
tioned, but to a carnivorous animal of enormous
fize, the race of which, fortunately for the prefent
inhabitants of the earth, feems now to be entire-
ly extinct *. The foundation of Dr Hunter’s
opinion is, that in thefe grinders the enamel is
merely an external covering; whereas, in the
elephant, and other animals deftined to live on
vegetable food, the enamel is intermixed with
the fubftance of the tooth +.

409. Though this argument appears to be of
confiderable weight, yet CAMPER, who was great-
ly {killed in comparative anatomy, and who had
ftudied this fubje&t with particular attention, was
of opinion, that thefe grinders belong to a fpecies
of elephant. This opinion he ftates in a let-
ter to Pallas, who had found grinders and o-
ther bones of this fame animal, on the weftern

Gg declivity

oO

* Phil. Tranf. vol. lviii. p. 3, &c.

+ A foffil grinder in the colle&tion of Joun Maccow-
AN, Efq; of Edinburgh, anfwers nearly to Mr Collinfon’s
defcription, and -is very well reprefented by the figure
which accompanies it. This grinder weighs four pounds
one-fourth avoirdupois ; the circumference of the corona
is eighteen inches; the coat of enamel is one-fourth of
an inch thick ; there are five double teeth; in Mr Col-

linfon’s {pecimen thete are only four.

466 ILLUSTRATIONS OF THE

declivity of the Oural mountains *. Camper
denies that the animal is carnivorous, becaufe
the incifores, or canine teeth, are wanting; and
he argues farther, from the weight of the head,
which may be inferred from the weight of the
grinders, that the neck muft have been fhort,
and the animal muft have been furnifhed witha
probofcis. He afterwards abandoned the latter
hypothefis, and gave it as his opinion, that the
incognitum was neither carnivorous, nor a fpecies
of the elephant +.

410. Neverthelefs, Cuvier, in a mémoire read
before the National Inftitute of Paris, maintains,
that the foffil bones of the new continent, as well as
moft of thofe of the old, belong to certain {pecies of
the elephant; of which, at leaft, two do notnow
exift, and are only known from remains preferved
in the ground. He diftinguifhes them thus f:

Elephas mammonteus,—maxilld obtufiore, lamel-

lis molarium tenuibus, rectis.

Elepbas Americanus,—molaribus multicufpidi-

bus, lamellis poft detritionem quadri-lobatis.

The latter fpecies, which is meant to include
the animal incognitum, is faid to have lived, not

only

* A&a Acad. Petrop. tom. i. (1777) pars pofterior,

p- 213, &c.
+ Ibid. tom. ii, (1784) p- 262.
+ Mémoires de l'Inftitut National, Sciences Phyfiques,

tom. ll. p. 19., &c,

HUTTONIAN THEORY. 467

, only in America, but in many parts of the old
continent. Yet fome late inquiries into the
W | ftructure of the teeth of graminivorous animals,
E and particularly of the elephant, make it very
l improbable that the incognitum has belonged to
F this genus*. The grinders of the elephant have
T been found to confift of three fubftances, ena-
mel, bone, and what is called the cru/ta petrofa,
] applied in layers, or folds contiguous to one ano-
ther; and no veftige of this ftructure appears in
og the perioders of the unknown animal ofthe Ohio +.
B Gg2 At

5 * See Mr Home's obfervations onghe teeth of gramini-
--yorous animals, Phil. Tranf. 799. Alfo, An sects on
the ftrudure of the teeth, by Dr Blake.

+ Ina paper inferted in the fourth volume of the A- ,
“merican Philofophical TranfaGtions, an account is given
of two different grinders that are found at the Salt-Licks
near the Ohio. One of them refembles the grinder of
the elephant, and may have belonged to the elephas
Americanus of Cuvier; the other agrees pretty nearly
with the grinder of Dr Hunter’s animal incognitum. The
author of the paper thinks that the animal incognitum was
“not wholly carnivorous, as the inci/ores, or canine teeth,

“are never found. At the Great Bone. Lick, bones of
{maller animals, particularly of the buffalo kind, have
been difcovered. The faline impregnation of the earth
at thefe Licks muft no doubt have contributed to the pre-
_fervation of the bones. Tranf. American Phil. Soc.

vol, iv. (1799) p. 510, &c.

468 ILLUSTRATIONS OF THE

At the fame time, Dr Hunter’s affertion, that this
animal was carnivorous, is rendered doubtful,
not only by the want of canine teeth, but alfo
from the refemblance between its grinders and
thofe of the wild boar, which Mr Home has ob-
ferved to be confiderable *. The grinder of the
boar is fimilar to that of the elephant, in the ex-
tent of the mafticating furface, but not at all in
the internal ftructure; and the fame is true of the
tooth of the animal incognitum, fo that a confidera-
ble probability is eftablifhed, that it and the boar
are of the fame genus, and both deftined to live
occafionally‘either on animal, or vegetable food.

411, Another anignal incognitum found in South

America has been deferibed by Cuvier, and ap-.

pears to be of a different genus from the incogni-
tum of the North. Thus, if we include the two
incognita of America, the elephas mammonteus,
the unknown buffalo of Pallas, and the great
animal of Bayreuth, we have at leaft five di-
ftinct genera, or fpecies of the animal kingdom,
which exifted on our continents formerly, but
do not exit on them now. The number is
probably much greater: Pallas mentions foffil
horns of a gazelle, of an unknown fpecies ; and
horns of deer aré often found, that cannot be re-
ferred to any fpecies now exilting. Thole ex-

tinct

* Obfervations on the grinding teeth of the wild boar
and animal incognitum. Phil, Tranf, 1801, p. 319.

5

HUTTONIAN THEORY. 469

tind races have been remarkable for their fize:
fome of the ancient elephants appear to have

] been three times as large as any of the prefent *.

412. The inhabitants of the globe, then, like all

F the other parts of it, are fubje& to change: Itis
not only the individual that perifhes, but whole
i fpecies,and even perhaps genera, are extinguifhed.
- It is not unnatural to confider fome part of this
_ change as the operation of man. The extenfion
= of his power would neceflarily fubvert the balance
that had before been eftablifhed between the in-
if habitants of the earth, and the means of their fub-
ly fiftence. Some of the larger and fiercer animals
| might indeed difpute with him, for a long time,
_ the empire of the globe; and it may have requi-
_ red the arm of a Hercules to fubdue the montfters
_ which lurked in the caves of Bayreuth, or roamed
l on the banks of the Ohio. But thefe, with others

of the fame charaéter, were at length extermina-

; ted: the more innocent fpecies fled to a diftance

_ from man ; and being forced to retire into the

| moft inacceffible parts, where their food was
_ feanty, and their migration checked, they may
have degenerated from the fize and ftrength of

_ their ancettors, and fome fpecies may have been

i ply extinguifhed.

But befides this, a change in the animal king-

dom feems to be a part of the order of nature,

Gg3 . and

* Camper, Nov, Acta Petrop. tom. ii. (1784) p. 257

4yo ILLUSTRATIONS OF THE

and is vifible in inftances to which human pow-

er cannot have extended. If we look tothe —

mof ancient inhabitants of the globe, of which
the remains are preferved in the ftrata them-
felves, we find in the fhells and corals of a for-
mer world hardly any that refemble exadly
thofe which exift in the prefent. The fpecies,
except in a few infltances, are the fame, but fub-
ject to great varieties. The vegetable impref-
fions on flate, and other argillaceous ftones, can
feldom be exaétly recognifed ; and even the in-
feéts included in amber, are different from thofe
of the countries in which the amber is found.
413. Suppofing, then, the changes which have
taken place in the qualities and habits of the ani-
mal creation, to be as great as thofe in their
ftruGure and external form, we can have no rea-
fon to wonder if it fhould appear, that fome have
formerly dwelt in countries from which the fi-
milar races are now entirely banifhed. The
power of living in a different climate, of endu-
ring greater degrees of cold or of heat, or of
fubfifting on different kinds of food, may very
well have accompanied the other changes.
Though one fpecies of elephant may now be
confined to the fouthern parts of Afia, another
may have been able to endure the feverer cli-
mates of the north ; and the fame may be true of
the buffalo or the rhinoceros. In all this no phy-
- : fical

HUTTONIAN THEORY. 471

T fical impoflibility is involved ; though whether
f jt is a probable folution of the difficulty concern-
T ing the origin of thefe animal remains, can only
| be judged of from other circumftances.

_. 414. If weconfider attentively the facts that re-
{pect the Siberian foffil bones, there will appear
jnfurmountable objections to every theory that
fuppofes them to be exotic, and to have been
prought into their prefent fituation from a di-
= ftant country.

The extent of the tra& through which thefe
bones are fcattered, is a circumftance truly won-
| derful. Pallas affures us *, that there is not a
» river of confiderable fize in all the north of Afia,
from the Tanais, which runs into the Black Sea,
to the Anadyr, which falls into the Gulf of
Kamtchatka, in the fides or bottom of which
bones of elephants and other large animals have
not been found. This is efpecially the cafe
_ where the rivers run in plains through gravel,
fand, clay, &c.; among the mountains, the bones
are rarely difcovered. The extent of the tract
juft mentioned exceeds four thoufand miles ; and
how the bones could be diftributed over all that
extent, by any means but by the animals having

Gg4 lived

* De Reliquiis Animalium exoticorum, per Afiam
i Borealem repertis.—Nov. Comment. Petrop. tom, xvii.
j j (1772) p. 576.

472 ILLUSTRATIONS OF THE

lived there, it feems impoflible to conceive. No
torrent nor inundation could have produced this
effect, nor could the bones brought in that way
have been laid together fo as to form complete
ikeletons,

415. One fac recorded by the fame author,
feems calculated to remove all uncertainty. Itis
that of the careafe of a rhinoceros, almoft entire,
and covered with the hide, found in the earth in
the banks of the river Wilui, which falls into the
Lena below Jacutfk *. Some of the mufcles
and tendons were actually adhering to the head
when Pallas received it. The head, after being
dried in an oven, is ftill preferved in the mu-
feum at Peterfburgh. The prefervation of the
fkin and mufcles of this natural mummy, as Pal-
las calls it, was no doubt brought about by its
being buried in earth that was in a ftate of per-
petual congelation ; for the place is in the pa-
rallel of 64°, where the ground is never thawed
but to a very {mall depth below the furface.

But by what means can we account for the

carcafe of a rhinoceros being buried in the earth,
on the confines of the polar circle? Shall we a-
{fcribe it to fome immenfe torrent, which, {weep-
ing acro{s the defarts of Tartary, and the moun-
tains of Altai, tranfported the produ@ions of In-

dia

* Pallas, ub: jupra, p. 86, Alfo, Voyages de Pallas,

tom. 1v. p. 13m.

ly

HUTTONIAN THEORY. 473

dia to the plains of Siberia, and interred in the
mud of the Lena the animals that had fed on the
banks of the Barampooter or the Ganges? Were
all other objections to fo extraordinary a fuppofi-
tion removed, the prefervation of the hide and
mufcles of a dead animal, and the adhefion of the
parts, while it was dragged for 2000 miles over
fome of the higheft and moft rugged mountains in
the world, is too abfurd to be for a moment ad-
mitted. Or fhall we fuppofe that this.carcafe has
been floated in by an inundation of the fea, from
fome tropical country now fwallowed up, and
of which the numerous iflands of the Indian

_ Archipelago are the remains? The heat of a

tropical climate, and the putrefcence naturally

_arifing from it, would foon, independently of all
other accidents, have ftripped the bones of their

covering. Indeed this inftantia fingularis, as in
every fenfe it may properly be called, feems cal-
culated for the exprefs purpofe of excluding eve-
ty hypothefis but one from being employed to
explain the origin of foffil bones. It not only ex-

cludes the two which have juft been mentioned,

but it excludes alfo that of Buffon, viz. that thefe
bones are the remains of animals which lived in
Siberia, when the ar&tic regions enjoyed a fine
climate, and a temperature like that which
fouthern Afia now pofleffes. From the preferva-
tion of the flefh and hide of this rhinoceros, it is

plain, that when the body was buried in the

earth,

474 ILLUSTRATIONS OF THE

earth, the climate was much the fame that it is
now, and the cold fufficient to refift the progrefs
of putrefaction.

Pallas takes notice of the inconfiftency of the
fate of this fkeleton, with the hypothefis of
Buffon; but he does not obferve that the incon-
fiftency is equally great between it and his own
hypothefis, the importation of the foffil bones by
an inundation of the fea, and that flefh or
mufcle muft have been entirely confumed long
before it could be carried by the waves to the
parallel of 64°, from any climate which the
rhinoceros at prefent inhabits.

416. The prefence of petrified marine objects in
places where fome of the foffil bones are found,
is no proof that the latter have come from the
fea, though it is produced as fuch both by Pal-
las himfelf, and afterwards by Kirwan. Thefe
marine bodies are the fhells and corals that have
been parts of calcareous rocks, from which being
detached by the ordinary progrefs of difintegra-
tion, they are now contained in the beds of fand
or gravel where the animal remains are buried.
They have nothing in common with thefe re-
mains; they are real ftones, and belong to ano-
ther, and a far more remote epocha. Such objects
being found in the fame place where the bones
lie, argues only that the {trata in the higher
grounds, from which the gravel has come, are
calcareous; and nothing can fhew ina ftronger

light

+ HUTTONIAN THEORY. 475

light the néceflity of diftinguifhing the different
condition of fofal bodies, united by the mere
circumftance of contiguity, before we draw any

inference as to their having a common origin.

If the marine remains were in the fame condi-
tion with the bones ; if they were in no refpe&
mineralized; then the conclufion, that both had
been imported by the fea, would have great
probability; but without that, their prefent union
muft be held as cafual, and can give no spit
into the origin of either.

417. On the whole, therefore, no conclufion re-
mains, but that thefe bones have belonged to
fpecies of elephants, rhinoceros, &c. which in-
habited the very countries where their remains
are now buried, and which could endure the
feverity of the Siberian climate. The rhinoce-
ros of the Wilui certainly lived on the confines
of the Polar circle, and was expofed to the fame
cold while alive, by which, when dead, its body
has been fo long, and fo curioufly preferved.

Thefe animals may alfo have lived occafion-
ally farther to the fouth, among the valleys
between the great ranges of mountains that
bound Siberia on that fide. Foffil bones are
but rarely found in thefe valleys, probably be-
caufe they have been wafhed down from thence 3
into the plains. We muft obferve, too, that
thofe animals may have migrated with the fea-
fons, and by that means avoided the rigorous

winter

476 ILLUSTRATIONS OF THE-

winter of the high latitudes. The dominion
of man, by rendering fuch migration to the
larger animals difficult or impoffible, muft have

greatly changed the economy of all thofe tribes, —

and narrowed the circle of their enjoyments and
exiftence. The heaps in which the foffil bones
appear to be accumulated in particular places,
efpecially in North America, have a great ap-
pearance of being connected with the migrations
of animals, and the accidents that might bring
multitudes of them into the fame fpot.

What holds of Siberia and of North America,
is applicable, a fortiori, to all the other places
where animal remains are found in the fame con-
dition. Thus we are carried back to a time
when many larger fpecies of animals, now en-
tirely extin, inhabited the earth, and when
varieties of thofe that are at prefent confined to
particular fituations, were, either by the liberty
of migration, or by their natural conftitution, ac-

commodated to all the diverfities of climate. This

period, though beyond the limits of ordinary
chronology, is pofterior to the great revolutions
on the earth’s furface, and the late among
geological epochas.

Note

Cia acticin aa aii

HUTTONIAN THEORY. 444

Nore xxtir. § 128.
Geology of Kirwan and De Luc.

418. The two champions of the Neptunian
fyftem, who have diftinguifhed themfelves moft
by their hoftility to Dr Hutton, are De Luc
and Kirwan. ‘They have carried on their at-
tack nearly on the fame plan, and have em-
ployed againft their antagonift the weapons both
of theology and fcience. With a fpirit as in-
jurious to the dignity of religion, as to the free-
dom of philofophical inquiry, they have difre-
ae garded a maxim enforced by the authority of Ba-
{con and by all our experience of the paft ; “ Tan-
a to magis bec vanitas inhibenda venit et coércenda,
quia, ex divinorum et humanorum male-fana admix-
tione, non folum educitur philofophia phantaftica,
Jed etiam religio heretica. Itaque falutare admo-
dum eft, fi mente Jobrid, fidei tantum dentur que
fidei funt *,”’

Proceeding

* The whole paflage is deferving of attention, and

| it feems as if the prophetic fpirit of Bacon had addrefled

E it to the cofmologifts of the prefent day. “ Peffima enim

j res eft errorum APOTSEOSIS, et pro pefte intelleétis habenda

i j eft, fi vanis accedat veneratio, Huic autem vanitati non-
|
j

nullt ex modernis fummd levitate ita indulferunt, ut, in pri-
mo capitolo GENESEQS, et aliis Scripturis Sacris, philofo-
phiam naturalem fundari conati funt : Inter viva queren-
tes MORTUA.” Nov. Organum, lib. i. aphor. 65.

478 ILLUSTRATIONS OF THE —

Proceeding, accordingly, in direct oppofition te
rules that have never yet been violated with im-
punity, and miftaking the true obje& of a theory
of the earth, they carry back their inquiries
to a period prior to the prefent feries of caufes
and effects, where, having neither experience
nor analogy to direct them, they pretend to be
guided by a fuperior light. They would have
us to confider their geological {peculations as a
commentary on the text of Moszs ; they endea-
vour to explain the action of creative power, and,
with indifcreet curiofity, would tear off the veil
which the hand of the prophet has fo wifely re-
fpected. But the veil cannot be torn off, and
all that is behind it muft be to man as that
which never has exitfted. |

419. M. de Luc has neverthelefs treated very
diffufely of the hiftory of the folar fyftem, pre-
vious to the eftablithment of the prefent laws of
nature, and has dwelt on it with great compla-
cency, and fingular minutenefs of detail. His
tenth letter to La Mrerueriz has the follow-
ing title :

“ On the Hiftory of the Earth, from the time
when that planet was penetrated by dight, till
the appearance of the fun; a portion of time
which includes the origin of heat, and of the
figure of the earth; of its primeval ftrata, of the
ancient fea, of our continents, as the bottom of

that

HUTTONIAN THEORY. 479

that fea, of the great chains of mountains, and
of vegetation *.”’

I muft confefs that lam unacquainted with eve-
ry thing of this letter but the title; and could not
eafily be prevailed on to follow any man who pro-
feffedly goes out of nature in fearch of knowledge;
who pretends to give the hiftory of our planetary
fyftem when there was no fun, and to enumerate
the events which took place between the exift-
ence of that lumimary, and the exiftence of
light. The abfurdity of fuch an undertaking
admits of no apology; and the {mile which it
might excite, if addrefled merely to the fancy,
gives place to indignation when it aflumes the
air of philofophic inveftigation.

420. It fets, however, in a ftrong light, the in-
confiftencies that may be obferved in the intellec-

` tual character of the fame individual, to confider

that the author of this trange and inconfiftent
reverie,

* Journal de Phyfique, tom. 37. (1790) partie 2de,
P. 332. As I may not have done juftice to this extra-
ordinary title, it may be right to prefent it in the origi-
nal. “ Sur PHiftoire de la TERRE, depuis que cette pla-
nette fut penetrée de LUMIERE, jufqu’s l’apparition du
SOLEIL; efpace de tems qui renferme les oRIGINES de
la chaleur, et de la figure de notre globe; de fes couches
primordiales, de L'ancienne mer, de nos continens, comme
fond de cette mer, de leurs grandes chaînes de mon-
tagnes, et de-la vegetation.”

480 ILLUSTRATIONS OF THE
reverie is, neverthelefs, an excellent obferver, and
well {killed in experimental inquiries. It will
hardly be believed that he who writes the hifto-
ry of the earth before the formation of the fun,
is verfed in the principles of inductive reafoning 3
and that he has added much to the ftock of geo-
logical knowledge, having obferved accurately,
and defcribed with great perfpicuity and can-
dour. His Lettres Phyfiques are full of valuable
and juft obfervations, though accompanied with
reafonings that do not feem always entitled to the
fame praife; and in another work he has fuc-
ceeded where many men of genius had failed,
and has made confiderable improvements in a
branch of the mathematics, without borrowing
almoft any affiftance from the principles of that
{cience *.

421. Some of the fame obfervations apply to

Mr Kirwan. His Geological Effays have alfo for

their object to explain the firft origin of things ;
and to fay that he has not fucceeded, in an at-
tempt where no man ever can fucceed, im-
plies no reproach on the execution of his work,
whatever it may do on the defign. We have
indeed no criterion by which the execution of
it can be eftimated: what would in any other
place be a blemifh, may be here deferving of
praife ; and if the work is full of confufion and

perplexity —

* Effai fur les Modifications de l’Atmofphere,

HUTTONIAN THEORY. 481

perplexity, thefe are qualities inherent in the
fubjec&t which it is intended to defcribe. It were,
no doubt, to be wifhed, that after emerging into
the regions of day, Mr Kirwan had been as fuc-
cefsful in copying the beauty and fimplicity of
nature, as in reprefenting the diforder and in-

le | q commiftency of the chaotic mafs. But his cof-

mology is without unity in its principles, or con-
fiftency in its parts: the caufes introduced, are,

for the moft part; fuch as will account for one

fet of appearances juft as well as for another;
or, if any of them is likely to prove inadequate

| to the effed afcribed to it, a new and arbitrary
_hypothefis is always ready to come to its aflift-

ance. The information given is feldom exact:

À a multitude of facts brought together, without

the order and difcuffion effential to precife know-
ledge; and an infinity of quotations, amaffed

= Without criticifm or comparifon, afford proofs of

extenfive reading, but of the moft hafty and fu-
perficial inquiry. Thus we have feen paffages
from Uxtoa and Frist, produced in fupport of
opinions, which, when fairly ftated, they had
the moft direct tendency to overthrow.

422. In one ref{peét, the geological writings of

_ Kirwan are far inferior to De Luc’s: They are

evidently the productions of a man who has not

feen nature with his own eyes; who has ftudied

Hh mineralogy

482 ILLUSTRATIONS OF THE

mineralogy in cabinets, or in books only; but
who has feldom beheld foffils in their native
place. With the balance in his hand, and the
external characters of WERNER in hjs view, he
has examined minerals with diligence, and has
difcovered many of thofe marks which ferve to
afcertain their places, in a fyftem of artificia?ar-
rangement. But to reafon and to arrange are
very different. occupations of the mind; and
a man may deferve praife as a mineralogift, who
is but ill qualified for the refearches of geo-
logy.

423. The fame hurry and impatience are vifi-
ble in the manner in which his argument againft
Dr Hutton is ufually conducted. He has feldora
been careful to make himfelf mafter of the opi-
nions of his adverfaries ; and what he gives as
fuch, and directs his reafonings againft, have of-
ten norefemblance to them whatfoever. With-
out any intention to deceive others, but deceived
himfelf, he ufually begins with mifreprefenting
Dr Hutton’s notions, and then proceeds to the re-
futation of them. In this imaginary conteft, it
will readily be fuppofed, that he is in general
fuccefsful: when a man has the framing both of
his own argument, and that of his antagonift, he
muit be a very unfkilful logician if he does not
come off with the advantage.

424. It

= E sso taii

HUTTONIAN THEORY. 483

424. It is but juftice, however, to the Neptu-
nifts, to acknowledge, that they are not all liable
tothe cenfure of beginning their refearches from
a period antecedent to the exiftence of the laws
of nature. This abfurdity does not, fo far as I
know, infect the fyftem of Werner. That mi-
neralogift has not propofed to explain the firft o-
rigin of things, though he has fuppofed, at fome
former period, a condition of the globe very
unlike the prefent, viz. the entire fubmerfion of
the folid under the fluid part.

Nore xxiv. § 129.
Sytem of Burron.

425. The affinity of Dr Hutton’s theory to

_ that of Buffon, is nothing more than what arifes

from their making ufe of the fame agents, viz.

fire and water, in producing the prefent condi-
_ tion of the earth’s furface. In almoft all other
refpeéts the two theories are extremely differ-
ent, The order in which tho e agents are em-

ployed in them, is dire@tly oppofite, as has al-
ready been remarked ; Buffon introducing the
action of fire firt, and of water only in the fe-
cond place, to wafte and deftroy mineral bodies,

Hi 2 and

484 ILLUSTRATIONS OF THE

and afterwards to difpofe them anew, and ar-
range them into ftrata. He makes no provi-
fion for the confolidation of thefe ftrata, nor any
for their angular elevation; he has no means of
explaining the unftratified rocks; nor any, but

one extremely imperfect, for explaining the in-.

equalities of the earth’s furface.

Again, Buffon miftook, in fome degree, the
true object of a theory of the earth ; and though
he did not go back, like the waclout Gatien named,
to a time when the laws of nature were not
fully eftablifhed, he begins from a condition of
things too unlike the prefent to be the bafis of
any rational fpeculation. He does not, indeed,
undertake to examine the flate of our planetary
fyftem before the fun exifted ; for from fuch ex-
travagance, even when moft difpofed to indulge
his fancy, he would furely have revolted. But
he treats of the world, when the earth and the
planets had juft ceafed to be a part of the fun, and
were newly detached from the body of that lu-
minary *.

This E concerning the origin of the
planets, contrived chiefly to account for the cir-

cumftance

* According to Buffon, the granite is the true folar
matter, unchanged but by its congelation.

HUTTONIAN THEORY. 48

cumftance of their motion being all in the fame
direction, and in other refpects not only unfup-
ported, but even inconfiftent with the principle
of gravitation, has nothing in common with a
theory, confined as Dr Hutton’s is, within the
field which mult for ever bound our inquiries,
and not venturing to fpeculate about the earth,
when in a condition totally different from the
prefent.

426. In what relates to the future, the two
fyitems are not more like than in what relates to
the paft. Buffon reprefents the cooling of our
planet, and its lofs of heat, asa procefs conti-
nually advancing, and which has no limit, but
the final extinétion of life and motion over all
the furface, and through all the interior, of the
earth. ‘The death of nature herfelf is the di-
ftant but gloomy obje@ that terminates our
view, and reminds us of the wild fiGions of the

Scandinavian mythology, according to which, an-
-mbilation is at laft to extend its empire even to the

gods. This difmal and unphilofophic vifion was
unworthy of the genius of Buffon, and wonder-
fully ill fuited to the elegance and extent of his
underftanding. It forms a complete contrat
to the theory of Dr Hutton, where nothing is
to be feen beyond the continuation of the pre-

fent order ; where no latent feed of evil threat-

ens final deftru@ion to the whole; and where the
Hh 3 movements

486 ILLUSTRATIONS OF THE

movements are fo perfect, that they can never
terminate of themfelves. This is furely a view
of the world more fuited to the dignity of Na-
TURE, and the wifdom of its Auror, than has
yet beert offered by any other fyftem of cofmo-
logy.

427. I have often quoted Buffon in the courfe
thefe I/luftrations, and mot commonly for the
purpofe of combating his opinions ; but I am
very fenfible, neverthelefs, of the obligations un-
der which he has laid all the fciences connect-
ed with the natural hiftory of the earth.

The extent and variety of his knowledge, the
juftnefs of his reafonings, the greatnefs of his
views, his correct tafte, and manly eloquence,
qualified him, better, perhaps, than any other
individual, to compofe the Hiftory of Nature.
The errors into which he has fallen, are almoft
all the unavoidable confequences of the circum-
ftances in which he was placed ; and if their a-
mount is eftimated by the proportion that they
bear to the general excellence of the work, they
will be reckoned but of fmall account. Buffon
began to write when many parts of natural hifto-
ry had made but little progrefs; when the quan-
tity of authentic information was fmall, and when
{cientific and corre@ defcription was hardly to
be found. Many of the greateft and moft im-
portant faéts in geology were quite unknown,

and

HUTTONIAN THEORY. 487

and {carcely any part of the mineral kingdom had
been accurately furveyed ; and, with fuch ma-
terials as this ftate of things afforded, it is not
wonderful if fome parts of the edifice he.erected
have not proved fo folid and durable as the reft.
Had he appeared fomewhat later; had he been
farther removed from the time when reafonings
a priori ufurped the place of induction ; and had
he been as willing to correct the errors into
which he had been betrayed by imperfeét in-
formation, as he was ingenious in defending
them, his work would probably have reached as
great perfection, as it is given for any thing
| without the {phere of the accurate fciences to
j

a ee ee E

ee ee ee ee aS

) attain. If he had examined the natural hiftory
: of the earth more with his own eyes, and been as
careful to delineate it with fidelity as force; if he
had liftened with greater care to the philofo-
_ phers around him ; had he attended to the de-
-monftrations of Newron more, and defpifed the
arrangements of Linnzus lefs; he would have
produced a work, as fingular for its truth as fot
its beauty, and would have gone near to merit
the eulogy pronounced by the enthutiafm of his
countrymen, MAJESTATI NATURÆ PAR INGE-
NIUM. |

Hh4 Norz

an estar alin

488 ILLUSTRATIONS OF THE

ju

w

Note x Bs

XV. $ 1303 A

ge 7 tb

Figure of the Earth. ie

E

428. That the earth is a fpheroidal body, gl
compreffed at the poles, or elevated at the equa- Sn
tor, is a fact eftablifhed by many accurate expe- tt
riments ; and though thefe experiments do not P
exactly coincide, as to the degree of oblatenefs y€

which they give to that fpheroid, they agree fuf-
ficiently to put it beyond all difpute, that the ; ft
earth, though folid, has nearly the fame figure
which it would affume if fluid, in confequence of
tts rotation on its axis.

Now, it is not at all obvious, to what phyfical Eo ‘
caufe this phenomenon is to be afcribed. The l
earth, as it exifts at prefent, has none of the
conditions that render the affumption of the fi- |
gure of equilibrium in any way neceffary to it. |
Conftituted as it is, its parts cohere with forces
incomparably too great to obey the laws of fta-
tical preffure, or to aflume any one figure rather
than another,’ on account of the centrifugal ten-
dency which refults from its revolution on its
axis. There is no neceflity that its fuperficies
fhould be every where level, or perpendicular to
the direction of gravity, nor that every two co-

lumns,

HUTTONIAN THEORY. 489

lumns, ftanding on the fame bafe, any where
within it, and reaching from thence to any two
points of the furface, fhould be of fuch weights
as precifely to balance one another. Neither of
thefe, indeed, is at all conformable to fad,
They are, however, the very fuppofitions on
which the determination of the {pheroid of e-
quilibrium is founded ; and as they certainly do
in no degree belong to the earth, it feems flrange
that the refult deduced from them fhould be ia
any way applicable to it. This coincidence
remains, therefore, to be explained ; and it muft
greatly enhance the merit of any geological fy-
ftem, if it can connect this great and enigmati-
cal phenomenon with the other fas in the na-
tural hiftory of the earth.

429. To eftablifh fuch a connection, has, ac-
cordingly, been a favourite object with geologitts,
whether they have embraced the Neptunian or
Vulcanic theory: both have thought that they
were entitled to fuppofe the primeval fluidity
of the globe, the one by water, and the other by
fire; and in whatfoever way that fluidity was
produced, the refult of it could be no other than
the {pheroidal figure of the whole mafs, agree-
_ ably to the laws of hydroftaties. If in this fluid
ftate the earth was homogeneous, the {pheroid
would be accurately elliptical, and the compref-

fion at the poles would be Saat the radius of

the

goo ILLUSTRATIONS OF THE

the equator ; if the fluid was denfer toward the
centre, the flattening would be lefs : and in either
cafe, the body, as it acquired folidity, may be
fuppofed to have retained its fpheroidal figure
with little variation. But though the fluidity
of the earth will account for the phenomenon of
its oblate figure, it may reafonably be queftion-
ed, whether this fluidity can be admitted, in
confiftency with other appearances. According
to what is eftablifhed above, none of the appear-
ances in the mineral kingdom indicate more
than a partial fluidity in any former condition
of the earth. The prefent ftrata, made up as
they are of the ruins of former ftrata, though
foftened by heat, have not been rendered fluid
by it, and have even poffeffed their foftnefs in
parts, and in fucceffion, not altogether, nor at the
fame time.

The unftratified, and more cryftallized fubs -

(tances, were caft in the bofom of others, which
were folid at the time when they were fluid. In
all this, therefore, there is no indication of a
fluidity prevailing through the whole mafs, or
even over the whole furface of the earth, and
therefore nothing that can explain the {pheroid-
al figure which it has acquired. The fuppofi-
tion, then, of the entire body of the earth, or
even of its external cruft, having been fluid,
though it might account for the compreflion at
the

\

es ee
BE.
E

HUTTONIAN THEORY. 49%

the poles, does not conneét that fact with the o-
ther facts in the natural hiftory of the globe, and
fails, therefore, in the point moft effential to a
theory. It is liable, alfo, to other objections ;

- whether it be conceived to have proceeded from
fire or from water ; whether it has happened on
the principles of Buffon or of Werner.

430. Firft, let us fuppofe that the fluidity of
the earth, or of the external cruft of it, at leaf
to a certain depth, proceeded from a folution
of the whole in the waters of the ocean; and,
waving all the objections that have been ftated
to this hypothefis, on account of the abfolute in-
folubility of many mineral fubftances in wa-
ter, let us fuppofe them all foluble in a certain
degree, and let us compute the quantity of the
menftruum, which, on the fuppofitions moft fa-
yourable to the fyftem, muft have been required
to this great geologico-chemical operation.

The filiceous earth, though not foluble in wa-
ter per fe, yet, after being diffolved in that fluid
by means of an alkali, was found by Dr Black,
in his analyfis of the Geyfer water, to remain
fufpended in a quantity of water, between 500
and 1000 times its own weight. This is one of
the facts moft favourable to the Neptunian the-
ory; and that every advantage may be given to
that theory, we fhall take the leaft of the num-
bers jut mentioned, and fuppofe that filiceous

earth

492 ILLUSTRATIONS OF THE

earth may be diffolved or fufpended in 500 times
its weight of water.

Taking this for the extreme degree of infolu-
bility of mineral fubftances, (though there are
many of which the infolubility is abfolute, or, to
{peak in the language of calculation, infinitely
great), we may fuppofe the infolubility of all the
reft, or the quantities of water in which they are
diffolved, to be ranged in a defcending feale
from goo to o, the extreme degree of deliquet-
cence. Then, taking the arithmetical mean be-
tween thefe extremes, it will give us 250, as the
proportion of water in which mineral fubftances
may at an average be diffolved. But this ave-
rage is much lefs than the truth ; for the quan-
tity of filiceous earth is great in comparifon of
any of the reft, and the mineral fubftances that
are extremely foluble in water are but in a {mall
quantity ; therefore, when we fuppofe mineral
bodies, at a medium, to be foluble in 250 times
their own weight of water, we make a fuppofi-
tion extremely favourable to the Neptunian fy-
ftem. :

431. This is the proportion between the weight
of the folvent, and of the fubftances held in folu-
tion: to have the proportion of their bulks, we
may fuppofe the fpecific gravity of mineral bo-
dies in general to be to that of water as 5 to 2,
and then we have the ratio of bulks, that of

250

—— SO
ls

HUTTONIAN THEORY. 493

i 2509X 5 to 2x1, or of 625 to r. It follows,
, then, that minerals in general cannot be fuppo-

fed foluble in lefs than 625 times their bulk of
' water.
4 432. Again, it muft be allowed to the Neptunifts,
that the fluidity of the whole earth is not ne-
ceflary to account for its affuming the {pheroidal
figure. Itis fufficient if the whole of that cruft
or fhell of matter was fluid, which is contained
between the actual furface of the terreftrial {phe-
roid, and the furface of the fphere infcribed with-
in it; that is, of the {phere which has for its
diameter the polar axis of the earth. The whole
` ofthe minerals which compofe this fhell, mutt
a at leaft have been diffolved in water, and have
| formed the chaotic mafs of Mr Kirwan. The
[ volume of the water required for this was not
lefs than 625 times the bulk of the {pheroidal
fhell that has juft been mentioned.

But, eis the difference between the polar

axis and the ‘equatorial diameter to be are the

‘latter, which i is the fuppofition moft kuuk to
the phenomena, it is eafy to fhew that the mag-
nitude of the above fpheroidal hell, or the dif-
ference between the folid content of the earth,
and the {phere infcribed in it, is greater than

= and lefs than a of the whole earth; fo

that

494 ILLUSTRATIONS OF THE

that the earth is lefs than 151 times the fphe-
roidal fhell.

The volume of the water, therefore, neceflary
to hold in folution the materials of this fhell, is
to the volume of the whole earth as 625 to 151,
or in a greater ratio than that of four to one: and
fuch, therefore, at the very leaft, is the quantity
of water which Mr Kirwan luppofes, after it cea-
fed to a& in its chemical capacity, to have reti-
red into caverns in the interior of the earth.
Thus the Neptunifts, in their account of the
fpheroidal figure of the earth, are reduced toa
cruel dilemma, and are forced to choofe be-
tween a phyfical and a mathematical impofli-
bility.

If we would inquire whether the opinion of
the igneous origin of minerals, as commonly re-
ceived by the Vulcanifts, is capable of affording
a better folution of this difficulty, the theory of
M. de Buffon is the firft that prefents itfelf.

433. That philofopher confiders the exiftence
of the {pheroidal figure as a proof that the whole
of the earth muft have been originally fluid ; and
as the fluidity of the whole can only be afcribed
to fufion, he has fuppofed that the earth was
originally a mafs of melted matter ftruck off
from the fun by the collifion of a comet; and
that this. mafs, when made to revolve on its

axis,

HUTTONIAN THEORY. 498

axis, put on a fpheroidal figure, which it has
retained, though now cooled down to congela-
tion. :

This fyftem need not be confidered in detail;
the foundation of it is laid in fuch defiance of
the principles of geometry and mechanics, that
the architect, notwithftanding all the fertility of
his invention, and all the refources of his genius,
was never able to give any folidity to the ftruc-
ture.

But it will be faid, that we may take a part
of the fyftem, without venturing on the whole,
and may fuppofe that the earth, or at leaft the
external cruft of it, has been fluid by fire,
though we do not inquire into the caufe of this

fire, or into the manner in which it was produ-

ced.

It is indeed true, that, when this is done, we
have not the fame fort of abfurdity to encoun-
ter that we met with in the Neptunian fy-
ftem, and that the Vulcanic theory does not,
like it, come into dire@ collifion with an axiom
of geometry. There are, neverthelefs, great
objections to it; for though all the pheno-
mena of the mineral kingdom atteft a flui-
dity of igneous origin, yet it is a fluidity that
was never more than partial; and though it
has been over all the earth, has been over it in
{ucceflion only. Befides, we are not entitled

to

496 ILLUSTRATIONS OF THE

to aflume the exiftence, and again the difappear-
ance of fuch a great quantity of heat, without af-
figning fome caufe for the change.

434. Since, then, neither the hypothefis of the
Neptunifts or the Vulcanifts, affords any good
explanation of the figure of the earth, or fuch
4 one as can connect it with the other appear-
ances in its natural hiftory, it remains to Im-
quire, whether the fyftem that fuppofes a partial
and fucceffive fluidity, like Dr Hutton’s, has
any refource for explaining this great phenome-
non. |

Of this fabje& Dr Hutton has not treated;
and when I was firk made acquainted with
his fyfiem, it appeared to me a very ferious ob-
jection to it, that it did not profefs to give an
explanation of fo important a fact as the oblate
figure of the earth: On confidering the matter
more clofely, however, I found that there were

principles contained in it from which a very fa-

tisfactory folution (and, I think, the only fatis-
faory folution) of that difficulty might be dedu-
ced. This folution I fhall endeavour to explain,
in as far, at leaft, as is neceffary for the purpofe
of general illuftration.

It is laid down in Dr Hutton’s theory, that
the furface of the earth is perpetually changed
by the detritus of the land; and that from the

materials

HUTTONIAN THEORY. 497

materials thus afforded, new horizontal ftrata
are perpetually formed at the bottom of the fea.
If this be true, and if the alternations of decay
and renovation have been often repeated, it is
certain, that the figure of the earth, whatever
it may have originally been, muft be brought °
at length to coincide with the {pheroid of equi-
librium. l
435. Here it is neceffary to remark, that the
expreflions, figure of the earth, and /urface of the
earth, are each of them occafionally taken in two
different fenfes.
The furface of the earth, in its moft obvious
` fenfe, is that which bounds the whole earth, and
includes all its inequalities ; it is a furface ex-
_ tremely irregular, rifing to the tops of the moun-
tains, def{cending to the bottoms of the valleys,
and having the continuity of its curvature often
interrupted, or fuddenly changed. This may
„be called the actual furface,and the figure bound-

i T ed by it, the actual figure, of the earth.

The furface of the earth, in another fenfe, is
one that is every where horizontal, and is the
fame which water affumes when at reft.
This fuperficies is ‘determined by the cir-
cumftance of its being conftantly perpendicular

to the direction of gravity; it is the furface

marked out by levelling, and may. be fuppo-
fed to be continued from the fęa, through the
‘ | Ti ;

interior

498 ILLUSTRATIONS OF THE

interior of the land, till it meet the fea again.
The figure bounded by this horizontal furface,
may properly be called the /fatical figure of the .
earth.

When it is gi that the figure of the earth
“is an oblate fpheroid, it is the ftatical, not the
aftual figure which is meant; and the de-
grees of the meridian which aftronomers mea-
fure, -are alfo referred to the Sapir icma of the
former.

436. Suppofe now a body like the. earth, but
i its a@tual figure infinitely more irregular,
having a fea circumfuled around it, the water
will defcend into the loweft fituations, and will `
fo atrange itfelf, that its furface fhall be per-
pendicular every where to the plumb-line, or
to the direction of gravity, in which ftate only
it can remain at reft. The figure of the fu-
perficies which the fea muft thus take will be

of a continuous curvature, and will return ins. a
to itfelf; though it may, if the actual figure ~

is very irregular, be far either from a {phere
or a fpheroid. If, however, we fuppofe the
folid parts of this mafs fubje& to be diffolved

or worn away, and carried down to the ocean, *

there will be a tendency td give to the whole
body the fame figure that it would have affumed,
if it had been entirely fluid, and fubje& to the

laws

4

= HUTTONIAN THEORY. 499

Jaws of hydroftatics. This tendency is the re-
fult of two principles.

437. Let us fuppofe the body juft deferibed to
have no rotation, fo that the particles of it are
o auated only by the forces of cohefion and of
attraction.

It is then clear, that every particle taken away
by attrition from the parts above the level of
the fea, and depofited under the furface-of it,
makes the general figure more compact, bring-
ing the remoter parts nearer to the centre of
gravity of the whole; fo that, in time, if the
body is homogeneous, “all the points of the furs
face will become equally diftant from. that cen-
tre. Thus the affual figure changes continually,
and approaches nearer to the ftatical, —

_ While this change is going forward in the
} Mual figure, there is another produced on the
= ftatical, that tends very much to accelerate the
ei coincidence of the two.
rs The effect of the inequalities of the bind. that
_ rife above the horizontal furface, i is, by their at-
traction, to render the parts of that furface imme-
- diately under them, more convex, ceteris pari-
* bus, than the reft. Again, where there are parts
of extraordinary depth in the fea, that is, where
- the folid and denfer parts are far removed from
the furface af the ocean, the curvature of the fu- -
a lia ae Lpoticlee

*

BOO ILLUSTRATIONS OF THE

perficies of the fea is thereby diminifhed, and that
fuperficies is rendered lefs convex than it would

be if the fea were fhallower. Thefe propofitions:

are both capable of ftri& mathematical demon-
itration. Hence the taking away of any particle
' of matter from the top of a mountain tends to di-
minith the curvature of the horizontal furface un-
der the mountain, where it is greateft; and the
depofition of the fame particle at the bottom of
the fea, tends to increafe the’curvature of this
fuperficies where it is leaft. The general ten-
dency, therefore, being to increafe the curva-
ture.where it is leaft, and to diminith it where it
is greateft, muft be to bring about an uniform
curvature throughout, that is, a fpherical figure.
Thus, by the wafte and fubfequent ftratification
of the land, the direction of gravity is continu-
ally altered ; it is more and more concentrated,
and the figure brought nearer to that which a
fluid would affume.

438. Ifnow we fuppofe the body to tee on
its axis, all other things remaining as before, the
furface bounding the fea will become different
from what it was in the former cafe, and will be
more fwelled out toward the middle or equatorial
regions. The land above the level of the fea will
itill, as before, be worn down and depofited in
the bottom of the fea, fo as to form ftrata nearly
parallel to its furface ; the tendency, therefore,

: 1S

os

HUFTONIAN THEORY; sot

is to render the real figure of the planet nearer

to the ftatical, At the fame time the /fatical fi-

gure is changed, as explained above; fo that the
two figures mutually approach, and the limit,
or ultimate figure to which they tend, is one.
over which the ocean might be diffufed every
where to the fame depth, for then the caufes of
change would entirely ceafe. But this figure is
no other thën the {pheroid of equilibrium, which,
therefore, is the effet which the wafte and re-
confolidation of the land would necefiarily pro-
duce, if the procefs were continued indefinitely,

without interruption, In this, asin many other `
inflances, when a body is fubje@ to the action

_ of caufes by which its form is gradually chan-

ged, the figure beft adapted to refift thofe chan-
ges, is the figure which the changes themfelves

ultimately produce,

Alfo, whatever be the irregularities of denfi-

s ty, the tendency to a change of figure will not

ceafe till the body is moulded into that particu-
lar fpheroid which admits of being covered with
water every where to the fame depth *. Thus

Bis. ite

A

* In the fame mariner as a tranfition i is thus made from
an irregular figure toa fpheroid of equilibrium, fo, if the
actual figure were at firft more Gimple than the {pheroid,
it would ftill be changed into this laft by degrees,

Let

602 ILLUSTRATIONS OF THE

it appears, that a folid of an irregular figure, and
of irregular denfity, provided it be in part co-
` vered

De E EGRO e
Let us conceive, for inftance, that the earth is at reff,
and is a perfe& {phere of folid matter, furrounded by an
ocean every where of equal depth, for example, of one
mile. Then, if a rotatory motion be communicated to
it, fo that it fhall revolve on its axis in twenty-four hours,
in confequence of the centrifugal force, the water circum-
fufed about the {phere will immediately rife up under the
equator, and will become part of a {pheroidal furface, (not

_ elliptical, but nearly fo), the equatorial diameter of which
is greater than the polar axis, in the ratio of 588 to 577-

By this means the water will be accumulated at the equa-

tor to the depth of nearly 2.5 miles, and form a zone fur-
rounding the earth, and extending about 37° on each
fide of the equator. The remainder of the furface will
be left dry, forming two vaft circumpolar continents,

that reach 53° on.every fide of the poles, and that are:

elevated in the middle more than four miles above the
level of the fea. |

Such would-be the ftate of our globe, on the hypothe-
fis above laid down; and, if there were no wafte or de-
ftru€tion of the land, this order of things would be per-

manent, and neither the folid nor fluid part of the mafs:

could ever acquire any other figure than that which has

been defcribed. But, if the fame laws be fuppofed

to regulate the action of the atmofphere in thofe circum-
ftances, that do a€tually regulate it according to the pre-
fent conftitution of the globe, the vapours raifed up from
the furface of the fea, would be carried by the winds

Over

HUTTONIAN THEORY. 503

vered with water; and be at the fame time fub-
ject to wafte above the furface of the fea, and
reconfolidation under it; has a tendency to ac-
quire, in time, the fame figure that it would have
megurted h had it beeti entirely fluid,

Tig 439. In

A

over the land, where they would be condenfed and preci-
pitated in rain. Thus, all the agents of deftruétion would
be let loofe on the two great circumpolar continents ;
rivers would be formed; the land would become deeply
interfected by ravines; thofe ravines would gradually
open into wide valleys; the maffes of greateft refiftance
would be fhaped into hills and mountains: and from
a fuperficies originally {mooth and uniform, the fame
inequalities would be produced which at prefent diver-
fify the furface of the earth.

While the parts of the {phere without the fpheroid
_ are thus continually diminifhed, the loofe earth and fand
wathed down from them, will be depofited at the bot-
` tom of the fea, and will form ftrata parallel to the fut-
face of the fuperincumbent water: The actual and fta-
tical figure are thus brought nearer one another; and,
at the fame time the ftatical is changed, on the principle
already explained (the change in the diré@ion of gravi-
ty), and is made continually to approximate to a fate,
which when it has attained, no farther change can take
place, viz. an oblate elliptic {pheroid, of which the fur-
face is perpendicular to the dire&ion of gravity, having
the equatorial diameter to the polar axis in the ratio of
230 to 229.

»

504 ILLUSTRATIONS OF THE

439. In the preceding reafonings, we have fup»
pofed the procefs of decay and fubfequent ftratifi-

cation to be carried on without interruption, till

the whole of the land is covered by the fea. This
fuppofition is ufeful for explaining the nature of
the forces-which have determined the figure of
the earth; but there is no reafon to think-that
it has ever been realized in its full extent, the
elevation of ftrata from the bottom of the fea in-
terrupting the progrefs, and producing new
land in one place as the old decays in another.
The very fame land alfo, which is wafted at its
furface, may perhaps be lifted up by the forces

that are placed under it ; or it may be let down, ~
undergoing alterations of its level, from caufes -

that we do not perceive, but of which the a@tion
is undoubted (§ 387). But notwithftanding thefe
interruptions, the general tendency to produce in

the earth a {pheroidal figure may remain, and `

more may be done by every revolution, to bring
about the attainment of that figure than to caufe
a deviation from it. This figure, therefore,
though never likely to be perfe@tly acquired,

will be the miting or afymptotic figure, if it may

be fo called, to which the earth will continually
approach.

440. If the preceding conclufions are juft, and
if the figure of equilibrium is only an afympto-
tic figure, to which that of the earth may ap-

proximate,

!

x
)

=

= +

I j n
(|
Y

HUTTONIAN THEORY. 50%

proximate, but cannot perfectly attain, we are
not to be furprifed if confiderable deviations
from it are actually obferved. This has accord-
ingly happened, infomuch, that the refults de.
duced from the moft accurate meafurement of
degrees of the meridian, differ from ‘one ano-
ther, in the oblatenefs they give to the earth, by
nearly one-half of the quantity to be determi-

ned. When we compare the degrees meafured

in France, and in fome other countries of Eu-
rope, with thofe meafured in Peru, we obtain

for the compreffion at the poles, lefs than ig of

_the radius of the earth. But when we compare

„the degrees meafured in France with one ano-
ther, and with thofe lately meafured in Eng-
land, we find that-they are beft reprefented by
a {pheroid that has its compreffion =a of its fe.
mi-axis*, There is reafon to think, therefore,
that the meridians are not elliptical ; and other
obfervations feem to fhow, that they are not even
fimilar to ‘one another ; or that the earth is not,
ftrictly {peaking, a folid of revolution ; fo, alfo, _

the comparifon of the degree meafured at the
Cape of Good Hope, with thofe meafured on the

oppolite

* Expofition du Syftéme du Monde, par La Place,
P- 61. 2d edit,

266 ILLUSTRATIONS OF THE

oppofite fide of the equator, creates a fufpicion; b
that the northern and fouthern hemifpheres are A
not perfectly alike, and that the earth is not e- fe
qually comprefied at the Arétic and the Antarctic o!
poles» Thefe irregularities, though they do not th
affect the general fa&t of the earth’s compreflion ec
at the poles, thew that the true ftatical figure is its
but imperfe&ly attained; and though this may ot
~ be accounted for, without having recourfe to the he
principles involved in our theory, it is in a mán- fir
ner very unfatisfatory, and, by help of fuppofi- br
tions, not at all confiftent with the original flui- or
dity afcribed to the whole mals, or to the exte- di
rior cruft of the earth. " ot

441. As the principles here iai down ii o'th
how a folid body may attain very nearly the | pl
figure which a fluid would acquire in order to ii
preferve its parts in equilibrio ; and fince the i
oblate figure belongs to other of the planets as |
well as the earth, and the globular to all the a
great bodies of the univerfe, this fuggefts an ana- in
logy that goes deep into the economy, of na- Ky
ture, and extends far beyond the limits within fa
which the mineralogift is wont to confine his fs
fpeculations.

442. That no very irregular figure is found ~ 4 S
among the planetary bodies, may therefore be E
confidered as a proof of the univerfality of that d ae
fyftem of wafte and reconfolidationthatwehave | th

been of

HUTTONIAN THEORY. so%

been endeavouring to trace in the natural hifto-
ry of the earth. A farther proof of the fame ari-
fes from confidering, that for every given mafs
of matter, having a given period of rotation,
there are two different {pheroids that anfwer the
conditions of eftablifhing an equilibrium among
its parts, the one near to the {phere, and the
other very diftant from it, and fo oblate as to
have a lenticular form. Thus the earth, fuppo-
fing it homogeneous, might either be in equili-
brio, by means of the figure which it actually has,
or of one in which the polar was to the equatorial
diameter as 1 to 768. The fame is true of the

` other planets; and yet we no where find that
ad ‘this highly comprefled fpheroid is a&tually em-
| ployed by nature. The reafon, no doubt, is, that

in fo oblate a {pheroid, the equilibrium between

"the gravitating and the centrifugal force is of the

kind that does not re-eftablifh itfelf when dif-
turbed ; fo that the parts let loofe, and not kept

in their place by firm cohefion, would fly off al-

together. In fuch a body, the wafte at the fur-
face would lead to an entire change of form, and -
therefore the conftitution here fuppofed could

not be permanent.

443. In the fyftem of atara, we have a great
deviation from the general order, which, never-

_ thelefs, has led to a very unexpected verification

of fome of the conclufions deduced above. A
principle

so8 ILLUSTRATIONS OF THE EP
principle extremely like that which is the bafis | b
of all the foregoing reafonings, led one of the | 8
greatet philòfophers of the prefent age to dif- | tl
cover the revolution of Saturn’s ring on its axis, ~ | th
and even to determine the velocity of that revolu- | ci
tion, fuch as it has been fince found by obferva- là
tion. La Pracer, laying it down as a maxim, that T pe
nothing in nature’can exift, where there are cau- ow
fes of change, not balanced or compenfated by br
other caufes *, concluded, that the parts of the as
ring muft be held from falling down to the body th
of the planet by fome other force than their mere i
cohefion to one another. Were it otherwife, every ‘s i K
particle detached from the ring, by any means, g
muf defcend in a Rraight line, almoft perpen-' ‘fo
dicular to the furface of Saturn; and the final dı
deftruction of the ring muft be inevitable. The | fe
only force that could balance this effe& of gra- z E
vitation, feemed to bea centrifugal force, ari-
fing from the rotation of the ring on an axis ~~
pafling through its centre, and perpendicular to of
its plane. La Place proceeded to inquire what f d
celerity of rotation was adequate to this effet, = | be
and found that one of ten hours and a quarter OV
would be required, which is almoft precifely an
the time afterwards determined by Dr Her- ` | di
scHEL from actual obfervation. If, with this | ag
: _ rotation, aa W
—— ec > x fu
* La Place, ubi fupra, p. 242.

`

HUTTONIAN THEORY. 509

N rotation, the ring is a folid annulus generated
by the rotation of a very flat ellipfis about a
given point in its greater axis, coinciding with
the centre of Saturn, it may be fo conftituted,
that the attraction of Saturn, combined with the
centrifugal force, may produce a force perpen-
dicular to its furface, and may enable detached
parts to remain at reft, animals, for inftance, to
walk on its furface, and fluids to be in equili-
brio. The fyftem of Saturn is thus fortified
againit the lapfe of time, as effectually as that of
_ the earth itfelf; and the means by which this

is accomplifhed, feem to prove, that the weapons
_ which time employs, are in both cafes the fame,
„viz. the flow wearing and decompofition of the

olid parts. This flow wearing may have pro-

duced the figure by which its a&tion is moft e£-
_, fefually refitted. :

444. Thus Dr Hutton’s theory of the earth
comes at laft to connect itfelf with the refearches
of phyfical aftronomy. The conclufion to be
drawn from this coincidence is to the credit of
both fciences. When two travellers, who fet
out from points fo diftant as the mineralogift
and the aftronomer, and who follow routes fo
different, meet at the end of their journey, and
agree in their report of the countries through
which they have paffed, it affords no flight pre-
fumption, that they have ‘kept the right way,

: ee and

ir
.

4)

i : » ee
E >-
f;

510 ILLUSTRATIONS OF THE

and that they relate what they have 2aually | d >
feen.
i | wpe
Nore xxvi. § 133. d tic
|
Prejudices relating to the Theory of the Earth, | A
445. Among the prejudices which a new the- |
ory of the earth has to overcome, is an opinion, |
held, or affected to be held, by many, that geo- | a
logical fcience is not yet ripe for fuch elevated { to
and difficult {fpeculations. ‘They would, there- 17
fore, get rid of thefe fpeculations, by moving the s ha
previous queftion, and declaring that at prefent col th
we ought to have no theory at all. We are not | fee
yet, they allege, fufficiently acquainted with the pa
phenomena of geology ; the fubje& is fo various al
and extenfive, that our knowledge of it muft for _ i all
a long time, perhaps for ever, remain extremely ; “ch
imperfe&. And hence it is, that the theories th
hitherto propofed have fucceeded one another fl
with fo great rapidity, hardly any of them ith
having been able to laft longer than the difcoyery ha
ofa new fad, or a fa& unknown when it wasin- ' fo
vented. It has proved infufficient to conneét this © : 2
fact with the phenomena already known, and has

therefore been juftly abandoned. In this man-
ner, they fay, have pafled away the theories of Je
Woodward, Burnet, Whifton, and even of Buf- i Pi
fon; TR

ee

a

‘HUTTONIAN THEORY. sır

, & “fon; and fo will pafs,*in their turn, thake of

Hutton and Werner.

446. This unfavourable view of geology, a
not, however, to be received without examina-
tion ; in fcience, prefumption is lefs hurtful than
defpair, and inactivity is more dangerous than
error. 3

One reafon of the rapid fucceffion of geolo-
gical theories, is the miftake that has been made
as to their object, and the folly of attempting
to explain by them the firft origin of things.
This miftake has led to fanciful {peculations that
had nothing but their novelty to recommend

them, and which, when that charm had cea-

fed, were rejected as mere fuppofitions, inca-
able of proof. But if it is once fettled, that
a E assy of the earth ought to have ‘no other

„aim but to difcover the laws that regulate the

changes on the furface, or in the interior of
the globe, the fubjeét is brought within the
{phere either of obfervation or analogy; and

_ there is no reafon to fuppofe, that man, who

has numbered the ftars, and meafured their
forces, fhall ultimately poe unequal to this in-

= veftigation.

447. Again, theories = have a rational ob-
je&, though they be falfe or imperfe&t in their
principles, are for the moft part approximations
to the truth, fuited to the information at the

time

LELEnE

5r2 ILLUSTRATIONS OF THE

time when they were propofed. They are fteps, A
therefore, in the advancement of knowledge, a
and are terms of a feries that muft end when gr
the real laws of nature are difcovered. It is, on | of
this account, rath to conclude, that in the revo-’ | ing
lutions of fcience, what has happened muft con- À
tinue to happen, and becaufe fyitems have chan- T the
ged rapidly in time paft, that they muft neceffa- — | ext
rily do fo in time to come. ; | anc

He who would have reafoned fo, aad who fes

had feen the ancient phyfical fyftems, at firft all Wi

‘yivals to one another, and then {wallowed up by | gré
the Ariftotelian; the'Ariftotelian phyfics giving thë
way to thofe of Des Cartes; and the phyfics of | fe
Des Cartes to thofe of Newton ; would have prez and
di&ed that thefe laft were alfo, in their turn, to | dep
give place to the philofophy of fome later period. . phe
This is, however, a conclufion that hardly any , 6G
one will now be bold enough to maintain, after | ae
a hundred years of the moft f{crupulous exami- | cda

nation have done nothing but add to the evie Th
dence of the Newron1an System. It feems | s

certain, therefore, that the rife and fall of theo- | 3 |
ries in times paf, does not argue, that the fame i
will happen in the time that is to come. pom
448. The multifarious and extremely diverfi- | adh
fied object of geological refearches, does, no doubt, . the
render the firft fteps difficult, and may very . Ply;
well Te

HUTTONIAN THEORY. = 373

well account for the inftability hitherto obfer-
ved in fuch theories; but the very fame thing
gives reafon for expecting a Very high degree
of certainty to be ultimately attained in thefe
inquiries.

Where the phenomena are few and fimple,
there may be feveral different theories that will
explain them in a manner equally fatisfa@ory ;
and in fuch cafes, the true and the falfe hypothe-
fes are not eafily diftinguifhed from one another.
When, on the other hand, the phenomena are
greatly varied, the probability is, that among
them, fome of thofe inflantie crucis will be
found, that exclude every hypothefis but one,
| E reduce the explanation given to the higheit
degree of certainty. It was thus, when the
_ phenomena of the heavehs were but imper-
-fely known, and were confined to a few ge-
neral and fimple faéts, that the Philolaic could
claim no preference to the Ptolemaic fyfem :
The former feemed a poflible hypothefis ; but
as it performed nothing that the other did

_ Mot perform, and was inconfiftent with fome

of our moft natural prejudices, it had but few
adherents. The invention of the telefcope, and
the ufe of more accurate inftruments, by multi-
plying and diverfifying the facts, eftablifhed its
credit; and when not only the general laws,
but alfo the inequalities, and difturbances of

Kk the

? ee

514 ILLUSTRATIONS OF THE

the planetary motions were wunderftood, all id
phyfical hypothefes vanifhed, like phantoms, J”
before the philofophy of Newron. Hence the A
number, the variety, and even the complica- th
tion of faéts, contribute ultimately to feparate. ia
truth from falfehood; and the fame caufes which, ob
in any cafe, render the firt attempts toward a 5°
theory difficult, make the final fuccefs of fuch wi
attempts juft fo much the more. probable. i oe
This maxim, however, though a general en- tio
couragement to the profecution of geological [ fec
inquiries, does. not amount to a proof that we- an
are yet arrived at the period when thofe inqui- in
ries may fafely affume the form of a: theory. | the
But that we are arrived at fuch a period, appears, ‘the
clear from other circumftances. | a
449. It cannot be denied, that a great multi- bra
tude of facts, refpecting the mineral kingdom, are the
now known with confiderable precifion ; and. por
that the many diligent and {kilful obfervers, who. ane
have arifen in the courfe of the laft thirty years, at
have produced. a great change in the ftate of geo- tole
logical knowledge. It is unneceflary to enu- | ar

merate them all; Frerper, Beraman, De Luc,
Saussure, DoLomiev, are thofe on whom Dr | í
Hutton chiefly relied; and it is on their obfer- j
vations and his own that his fyftem is founded. p
If it be faid, that only a fmall part of the earth’s
furface has yet been Boba and defcribed. oh
y

with

HUTTONIAN THEORY: BIg

with fuch accuracy as is found in the writers
juft named, it may be anfwered, that the earth
is conftructed with fuch a degree of uniformity,
that a tract of no very large extent may afford
_ inftances of all the leading facts that we can ever
© obferve in the mineral kingdom. The variety of
geological appearances which a traveller meets
with, is not at all in proportion to the extent of
country he traverfes ; and if he take ina por-
tion of land fufficient to include primitive and

: fecondary trata, together with mountains, rivers,
and plains, and unftratified bodies in veins and
| in maffes, though it be not a very large part of

the earth’s furface, he may find examples of all
p moft important facts in the hiftory of foffils.

Though the labours of mineralogifts have em-
braced but a fmall part of the globe, they may
_ therefore have comprehended a very large pro-
portion of the phenomena which it exhibits ;
and hence a prefumption arifes, that the outlines,
at leaft, of geology have now been traced with
tolerable truth, and are not fufceptible of great
Variation.

450. When the phenomena of any clafs are in
general ambiguous, and admit of being ex-
plained by different or even oppofite theories ;
if few of thofe exclufive fads are known, which
admit but of one or a few folutions, then we
f have no right to expe& much from our en-
deavours to generalize, except the knowledge

mT

Bk of

ae

s16 ILLUSTRATIONS OF THE

of the points where our information is moft de- i
ficient, and to which our obfervations ought ©

chiefly to be directed. But that many of the bi
exclufive and unambiguous inftances are known, I
in the natural hiftory of the globe, I think is of
evident from the reafoning in the foregoing pa- the
ges, where fo many examples have occurred of Ve
appearances that give the moft direct negative fte
to the Neptunian fyftem, and exclude it from afl

the number of poflible hypothefes, by which the
phenomena of geology can be explained. The

a
be
Ce)

abundance of fuch inftances is an infallible fign, -Sa
that the mais of knowledge is in that ftate of fer- i thg
mentation, from which the true theory may be — tio
expected to emerge. | he

451. Another indication of the fame kind, is the | po
neat approach that even the moft oppofite theo- fer
ries make, in fome refpects, to one another. p
There are fo many points of contact between nal
them, that they appear to approximate to an ùl- | the
timate ftate, in which, however unwillingly, | in,
they muft at laft coincide. That ultimate form, | of

too, which all thefe theories have a tendency to
put on, if Iam not deceived, is no other than
that of the Huttonian theory. F

452. The firft example I fhall take from the

ay

fyftem of Sauffure. It is to be regretted, that ih
this excellent geologift has no where given us a cs
complete account of his theory. Some of the | i
Ne

leading

si Sa

HUTTONIAN THEORY. 517

leading principles of it are, however, unfold-
ed in the courfe of his obfervations, and ena-
ble us to form a notion of its general outline.
It was evidently far removed from the fyftem
of fubterraneous heat, and feems, efpecially in
the latter part of the author’s life, to have been
very much accommodated to the prevailing fy-
ftem of Werner. Neverthelefs, with fo little
affinity between their general views, Sauffure
and Hutton agree in that moft important. ar-
ticle which regards the elevation of the ftrata.
Sauffure plainly perceived the impoflibility of
the ftrata being formed in the vertical fitua-
tions which fo many of them now occupy; and

he takes great pains to demonftrate this im-
poflibility, from fome facts that have been re~

ferred to above. He alfo believed that this ele-
vation had been given to ftrata that were origi-
nally level, by a force directed upwards, or by
the refoulement of the beds, not by their falling
in, as is the opinion of De Luc and fome other
of the Neptunitts.

Now, whoever admits this principle, and rea-
fons on it confiftently, without being afraid to
follow it through all its confequences, muft un-
avoidably come very clofe to the Huttonian
theory. He muft fee, that a power which, a&t-
ing from below, produced this great effect, can
never have belonged to water, unlefs rarefied

Kk 3 into

a

s18 ILLUSTRATIONS OF THE `

into team by the application of heat. But if it | Di

be once admitted that heat refides in the mine- ft
ral regions, the great objection to Dr Hutton’s i
fyftem is removed ; and the theorift, who was ii
furnifhed with fo a&ive and fo powerful an

agent, would be very unfkilful in the manage- ie

ment of his own refources, if he did not employ `

it in the work of confolidating as well as in that lo
of raifing up the ftrata. A little attention will |
fhew, that it is qualified for both purpofes ; th
though infuperable objeCtions mutt, no doubt, .

offer themfelves, where the effets of compref- 9
fion are not underftood, We may fafely con- th
clude, then, that the accurate and ingenious Ore- he
ologift of Geneva ought to have been a Piu- | oe
zonift, in order to give conliftency to the princi- hi
ples which he had adopted, and to make them coa- af
lefce as parts of one and the fame fyftem. If he | de
embraced an oppofite opinion, it probably was it
from feeling the force of thofe objections that ca
arife from our difcovering nothing in the bowels D
of the earth like the remains left by combuftion, ce
or inflammation, at its furface. The fecret by th
which thefe feeming contradictions are to be re- | th
conciled, was unknown to this mineralogift, and a
he has accordingly decided ftrongly againft the a
action of fire, even in the cafe of thofe unftratified ae
fubftances that have the ereateft affinity to vol- S
canic lava. l f

453. The

HUTTONIAN THEORY. s519

453. The theoretical conclufions of another ac-
curate and {kilful obferver, Dolomieu, furnifh a
ftill more remarkable example of a tendency to
union between fyftems profefledly hoftile to one
another.

This ingenious mineralogift, obferving the in-
terpofition of the bafalt between ftratified rocks,
fo that it had not only regular beds of fandftone
for its bafe, but was alfo covered with beds of
the fame kind, faw plainly that thefe appearan-
ces were inconfiftent with the fuppofition of

=. common volcanic explofions at the furface. He

therefore conceived, that the volcanic eruption
had happened at the bottom of the fea, (the le-

vel of which, in former ages, had been much
higher than at prefent), and that the materials -

afterwards depofited on the lava, had been in
length of time confolidated into beds of ftone.

ft is evident, that this notion of fubmarine vol-

canoes, comes very near, in many refpedts, to
Dr Hutton’s explanation of the fame appearan-
ces. If the only thing to be accounted for were
the phenomenon in queftion, it cannot be denied
that Dolomieu’s hypothefis would be perfe@ly
fufficient ; but Dr Hutton, to whom this phe- |
nomenon was familiar, and who, like Dolomieu,
conceived the bafalt to have been in fufion, was
convinced that the retreat of the fea was not a
fact weil attefted by geological appearances, and

Kk4 if

s20 ILLUSTRATIONS OF THE

if admitted, was inadequate to account for the
facts ufually explained by it. He conceived,
therefore, that fuch lava as the preceding had
flowed not only at the bottom of the fea, but
in the bowels of the earth, and having. been
forced up through the fiffures of rocks already
formed, had heaved up fome of thefe rocks, and

interpofed itfelf between them. This agrees -

with the other facts in the natural hiftory both
of the bafaltes and the ftrata.

It is plain, that, in this, there is a great ap-
proach of the two theories to one another : both
maintain the igneous origin of bafaltes, and its
affinity to lava; both acknowledge that this la-
va cannot have flowed at the furfaee, and that
the ftrata which cover it have been formed at
the bottom of the fea. They only differ as to
the mode in which the fubmarine or fubterra-
neous volcano produced its effect, and that dif-
ference arifes merely from the one geologift ha-
ving generalized more than the other. Dolo-

nieu fought to connect the bafalt with the la-
vas that proceed from volcanic explofions at the
furface; Dr Hutton fought not only to conned
thefe ens appearances with one another, but al-
fo with the other phenomena of mineralogy,
particularly with the veins of bafaltes, and the
elevation of the ftrata.

- 454.In

HUTTONIAN THEORY. sas

- 454. In another point, the coincidence of Dolo-
mieu’s opinions and Dr Hutton’s is ftill more
ftriking. The former has remarked, that many
of the extinguifhed volcanoes are in granite
countries, and that, neverthelefs, the lavas that
they have erupted contain no granitic ftones, `
There muft be, therefore, fays he, fomething un-
der the granite, and this laft is not, at leaft in all
cafes, to be confidered as the bafis of the miné-
ral kingdom, or as the body on which all others
reft. In this fyftem, therefore, granite is not
always a primordial rock, any more than in Dr
Hutton’s. :

But Dolomieu makes a {till nearer advance
to the Huttonian theory; for he {uppofes, that
under the folid and hard cruft of the globe,
there isa {phere of melted ftone, from which
this bafaltic lava was thrown up. The fyftem
of f{ubterraneous heat is here adopted in its ut-
moft extent, and in that form which is confider-
ed as the moft liable to objection, viz. the exift-
ence of it at the prefent moment, in fuch a de-
gree as to melt rocks, and keep them in a ftate
of fufion. In this conclufion, the two theories
agree perfectly; and if they do fo, it is only be-
caufe the nature of things has forced them into
union, notwithftanding the diffimilitude of their
fundamental principles,

This

g22 ILLUSTRATIONS OF THE

This ought to be confidered as a ftrong proof,
that the phenomena known to mineralogifts are
fufficient to juftify the attempts to form a theo-
ry of the earth, and are fuch as lead to the fame
conclufions, where there was not only no pre-
vious concert, but even a very marked oppofi- as
tion. Ihave already obferved, that there is a |
greater tendency to agree among geological theo-
ries, than among the authors of thofe theories.

455. Another circumftance worthy of confide- l
ration is, that in the fearch which the Neptunifts
have made, for facts moft favourable to the aque-

ous formation of minerals, we find hardly any of ‘
a kind that was unknown to the author of the i
fyftem here explained. The appearances on oe

which WERNER grounds his opinion with re- i
fpe& to bafaltes, and by which he would ex- )
clude the adion of fire from any fhare in the
formation of it, are all comprehended in the ;
alternation of that rock with beds, or ftrata ;
obvioufly of aqueous origin. Now thefe ap-
pearances were well known to Dr Hutton, and a
are eafily explained by his theory, provided the |
effets of compreflion are admitted. From this,
and the other circumftances juft obferved, | am
difpofed to think, that the great facts on which
every geological fyftem muft depend, are now
known, and that it is not too bold an anticipa-
tion to fay, that a theory of the earth, which
explaing _

HUTTONIAN THEORY. 523

explains all the phenomena with which we are
at prefent acquainted, will be found to explain
all thofe that remain to be difcovered.

456. The time indeed was, and we are not yet
far removed from it, when one of the moft im-
portant principles involved in Dr Hutton’s theo-
ry was not only unknown, but could not be dif-
covered. This was before the caufticity produ-
ced in limeftone by expofure to fire was under-
ftood, and when it was not known that it arofe
from the expulfion of a certain aerial fluid, which
before was a component part of the ftone. It
could not then be perceived, that this aerial part
might be retained by preflure, even in fpite of
the action of fire, and that in a region where
great compreflion exifted, the abfence of cautti-
city was no proof that great heat had not been
applied. The difcoveries of Dr Biack, therefore,
mark an era, before which men were not qualified
to judge of the nature of the powers that had ~
acted in the confolidation of mineral fubftances.
Thofe difcoveries were, indeed, deftined to pro-
duce a memorable change in chemiftry, and in
all the branches of knowledge allied to it; and
have been the foundation of that brilliant pro-
grefs, by which a collection of praical rules,
and of infulated facts, has in a few years rifen
to the rank of a very perfect fcience. But even
before they had explained the nature of carbo-

nic

z224 ILLUSTRATIONS OF THE

pic gas, and its affinity to calcareous earth, I am i
not fure but that Dr Hutton’s theory was, at ‘
leaft, partly formed, though it muft certainly f
have remained, even in his own opinion, expo- f
fed to great difficulties. His active and penetra-
ting genius foon perceived, in the experiments
£ his friend, the folution of thofe difficulties,
and formed that happy combination of princi- ;
ples, which has enabled him to explain the moft 5
enigmatical FRERE in the natural hiftory of $ !
the earth. . o i
As we are not yet far removed from the time p *
when our chemical knowledge was too imperfect ¥
to admit of a fatisfatory explanation of the phe- | t
nomena of mineralogy, fo it is not unlikely that Š
we are approaching to other difcoveries that ae.
are to throw new light on this fcience. It Ls
would, however, be to argue ftrangely to fay, ce.
that we muĝ wait till thofe difcoveries are =
made before we begin any theoretical reafon- a:
ings. If this rule were followed, we fhould t
not know where the imperfections of our fcience €
lay, nor when the remedies were found out, Pee
fhould we be in a condition to avail ourfelves of {
them. Such condu& would not be caution, but í
timidity, and an excefs of prudence fatal to all 1
philofophical inquiry. i
457. The truth, indeed, is, that in phyfical in-
quiries, the work of theory and obfervation muft

go

HUTTONIAN THEORY. 525

go hand in hand, and ought to be carried on at
the fame time, more efpecially if the matter is
very complicated, for there the clue of theory is
neceflary to direct the obferver. Though a man
may begin to obferve without any hypothefis, he
cannot continue long without feeing fome ge-
neral conclufion arife ; and to this nafcent theo-
ry it is his bufinefs to attend, becaufe, by feek-
ing either to verify or to difprove it, he is led
to new experiments, or new obfervations. He
is led alfo to the very experiments and obferva-
tions that are of the greateft importance, namely,
to thofe inflantie crucis, which are the criteria
that naturally prefent themfelves for the trial of
every hypothefis. He is conducted to the places
where the tranfitions of nature are moft percepti-
ble, and where the abfence of former, or the pre-
fence of new circumftances, excludes the action of
imaginary caufes. By this correction of his firit
opinion, a new approximation is made to the
truth ; and by the repetition of the fame procefs,
certainty is finally obtained. Thus theory and
obfervation mutually affift one another; and the
fpirit of fyftem, againft which there are fo ma-
ny and fuch jut complaints, appears, nevertlic-
lefs, as the animating principle of induive in-
vettigation. The bufinefs of found philofophy is
not to extinguifh this fpirit, but to reftrain and
dire@ its efforts. |

458. It

226 ILLUSTRATIONS OF THE

458. It is therefore hurtful to the progrefs of
phyfical fcience to reprefent obfervation and

theory as ftanding oppofed to one another. Berg- —

man has faid, ‘‘ Obfervationes veras quam in-
geniofiffimas fictiones fequi preeftat ; nature my-
{teria potius indagare quam divinare.”

If itis meant by this merely to fay, that it is
better to have fađts without theory, than theory
without facts, and that it is wifer to inquire into
the fecrets of nature, than to guefs at them, the
truth of the maxim will hardly be controverted.
But if we are to underitand by it, as fome may
perhaps have done, that all theory is mere fiction,
and that the only alternative a philofopher has, is
_to devote himfelf to the ftudy of facts unconnect-
ed by theory, or of theory unfupported by facts,
the maxim is as far from the truth, as I am con-
vinced it is from the real fenfe of Bergman.
Such an oppofition between the bufinefs of the
theorift and the obferver, can only occur when
the fpeculations of the former are vague and in-
diftinct, and cannot be fo embodied as to become
vifible to the latter. But the philofopher who
has afcended to his theory by a regular genera-
lization of fas, and who defcends from it again
by drawing fuch palpable conclufions as may be
compared with experience, furnifhes the infalli-
ble means of diftinguifhing between perfect fei-
ence and ingenious fiction. Of a geological theory

that

HUTTCNIAN THEORY. 527

that has ftood this double teft of the analytic and
fynthetic methods, Dr Hutton has furnifhed us
with an excellent inftance, im his explanation of
granite. The appearances which he obferved
in that ftone led him to conclude, that it had
been melted, and injected while fluid, among the
ftratified rocks already formed. He then confi-
dered, that if this is true, veins of granite muft
often run from the larger mafles of that ftone,
and penetrate the {trata in various directions ;
and this muft be vifible at thofe places where
thefe different kinds of rock come into conta&
with one another. This led him to fearch in
Arran and Glen-tilt for the phenomena in quef-
tion; the refult, as we have feen, afforded to his
theory the fulleft confirmation, and to himfelf
the high fatisfaG@tion which muf ever accompa-
ny the fuccefs of candid and judicious inquiry.
459. It cannot, however, be denied, that the
impartiality of an obferver may often be affe&ted
by fyftem; but this is a misfortune againtt
which the want of theory is not always a com-
plete fecurity. The partialities in favour of opi-
nions are not more dangerous than the prejudi-
ces againft them ; for fuch is the fpirit of fy ftem,
and fo naturally a all men’s notions tend to re-
duce themfelves into fome regular form, that the
very belief that there can be no theory, becomes
a theory itfelf, and may have no inconfiderable

{way
R <

s . z pie EAE CAEN S
f
Í

228 ILLUSTRATIONS, &c.

{way over the mind of an obferver. Befides, one |
man may have as much delight in pulling down,
as another has in building up, and may choofe
to difplay his dexterity in the one occupation as
well as in the other. The want of theory, then,
does not fecure the candour of an obferver, and
it may very much diminihh his fkill. The difci-
pline that feems beft calculated to promote both,
Gs a thorough knowledge of the methods of in-
ductive inveftigation ; an acquaintance with the
hiftory of phyfical difcovery ; and the careful
ftudy of thofe fciences in which the rules of phi-
lofophizing have been mof fuccefsfully applied.

FINIS.

RE SEES PEM E CAEN ED SSCA NF MARNE SALA RENE LP EEE ROR RS PRI LITRE IRN E

DEEE ES LN

\
V