An elementary treatise on Geology: determining fundamental points in that science, and containing an examination of some modern geological systems, and particularly of the Huttonian theory of the earth ... Translated from the French manuscript by ... H. De la Fite

Preface

. 1 HE friendship, with which I am honoured by Mr. De Luc, induced him some time ago to communicate to me a Treatise on Geology, intended for the French Press. He was desirous that this work should appear in England, which he has for thirty-six years considered as his native country; and at his re quest, I ventured to undertake the following translation, which has been conducted and completed under his immediate inspection. In revising his work, previously to its trans lation, some alterations occurred to the author as expedient. The French and English pub lications will therefore occasionally differ.' The Letters also to Dr. Hutton, published a 2 in iti the Monthly Review, are omitted in this work, though inserted in the original now printing at Paris. To establish some fundamental points in Geology, is the principal object of Mr. De Luc; an object necessarily connecting almost every branch of the physical sciences, with the History of the Earth.

This is clearly shown in the following pages, and the attention of the student ia directed to the precise points of natural philosophy and natural history, embraced by geology, and which have long excited a considerable interest. Mr. De Luc has not ye\ been able to pre pare for publication his earlier travels in Swit zerland and in Germany, from the year 1782 to 1799** But he considers those which will shortly appear in English, containing his observations on some parts of the coasts of the Baltic and North Seas, and in different parts of England, as sufficient to establish all the propositions of the theory, the critical discussion of which forms the subject of the present work. It V It has been justly observed that the discoveries in the physical sciences, of which recent times may boast, are to be ascribed to the influence of those rules of legitimate philosophy which were established by Lord Bacon two centuries ago.

To these rules no philoso pher has more scrupulously adhered than the excellent author of this work; and while he has thus largely contributed to rescue geological science from the disgrace of visionary theories, he has advanced a system which makes a strong appeal for its truth to facts easily verified, if their certainty be disputed. The origin and nature of Man form the ultimate objects of Mr. De Luc's inquiries. A knowledge of the History of man, he has observed, is indispensably necessary in order to investigate with success these most interest- O ing subjects: and as his History is intimately connected with that of the planet which he in habits, it becomes requisite to study with attention the monuments of the revolutions which the surface of the globe has undergone, together VI together with the causes which have produced them.

The results of Mr. De Luc's long and labo rious researches have supplied an additional proof in support of revealed Religion, Ho has made it appear that the very facts upon which those systems seemed to rest, which as sign an indefinite antiquity to our present con tinents, confirm, on the contrary, in the most satisfactory manner, the chronology of Gene sis; and he has successfully traced the striking analogy that subsists between the great Volume of Nature, and the sacred page of Revelation. Thus he has shown, that the revolution which, according to every fact of geology, gave birth to our continents, was effected at the epoch of the Deluge, as it is described in the Mosaic History; and thus likewise he has demon strated the conformity of geological monu ments with the sublime account of that series of operations which took place during the Sir Days, or periods of lime, recorded by the inspired penman.

Mr. Mr. De Luc's Geological Letters to Pro fessor Blumenbach, in the British Critic for 179-i and 179*5, were intended to point out those connexions : he seldom alludes to them in this work, the subject of which is purely philosophical: but the last of these Letters, on account of its very interesting nature, is, with the author's consent, reprinted here as an Appendix. The numerous extracts from M. de Saus sure's Voyages dans les Alpes, adduced by Mr. De Luc in confirmation, either of his system, or of his personal observations, will form, it is presumed, a valuable part of this volume; and they will prove the more accept able to the English reader, as no translation of the Travels of that eminent geologist into our language, has yet appeared. HENRY DE LA FITE. WHILE this work was in the press, Dr. Hales's first volume of his New Analysis qf Chro nology, 8)C. appeared ; and on that publication Mr, De Luc has communicated to the translator the following remark*. — " I regret that the Rev.* Dr. Hales, " in his work just published, has deemed it necessary " to animadvert upon my Geological system, from " some misconceived notions of it; classing me among " the Geologists who have thought — That the ante " diluvian mountains did not exceed 50 toises in " height; — And that before the Deluge, the eartlis " axis was perpendicular to the plane of the ecliptic, " and that its present obliquity took place at the " Deluge, which occasioned an alteration in the " earth's centre qf gravity.

P. 329- If Dr. Hales " had read my works, or only the Vith of my Let " ters to Professor Blumenbach, in the British " Critic of 1795, (which, as containing a general " view of the agreement of my system with Genesis, *•' is, in conformity to your wish, to be subjoined to " your translation) he would, in the first place, have " seen, that I never attempted to fix the height of " the antediluvian mountains, a point wholly indif " ferent to my system. And with respect to changes " in the earth's motions, he would have perceived " that I considered those which I have mentioned, " not as a cause of the Deluge, but as consequences " which might have influenced the astronomical ob- '■' servations X a servations subsequent to that event. On this *" subject, Dr. Hales may see, in a review of Mr. " Phil.

Howard's work, The Scriptural History " of the Earth, 8$c. (British Critic, August 1797, " p. 108,) that these small changes are adduced as " accounting for the remarkable circumstance of the " antediluvian year consisting only of 360 days. *** This circumstance served as the foundation of the " ancient astronomical formula?, transmitted by " Noah to the Asiatic nations; formulas which, " however accurate with regard to the antediluvian ***" state of the earth, had subsequently required cor " rections, on account of a greater number of days " in the year, i. e. of revolutions of the earth on its " axis, while describing the same orbit." SUMMARY VIE W OF THE CONTENTS. PRELIMINARY DISCOURSE ON GEOLOGY. <j 1. Geology the most extensive and the most complex of sciences. 2. The too hasty assignment of causes to past effects has produced various contradictory Theories of the Earth. 3.

The history of the Earth inseparably connected with that of Man. 4. Geology a science useless to mankind, till brought forward in the systems of modern philosophers ; the history of the earth and of the human race having been sufficiently made known by the Mosaic records, and by Pagan traditions derived from a similar source. 5. All information essential to men on this subject had thus been afforded them by Revelation. 6*. But Geology having been represented by some authors as in opposition to the history of Muses, the study of this science is on that ticcount become essential to Divines. 7. The duties and the destination of men involved in a question which concerns their origin. 8. The first geological systems contrary to Genesis have fallen to the ground. 9- Those in defence of Genesis equally premature. 10.

Importance of establishing some fundamental points in Geology. 11. Mr. Playfair's Illustrations of the Hut tonian Theory one of the latest and most methodical works on this science. 1*2. Dr. Hutton had formed a general system from some mincralogical details. 13. Mr. Playfair's statement of the great extent of knowledge required in geology. 14. Ill consequences of scepticism in this science. 15. General motives ad duced with reason by Mr. Playfair for hoping that truth in geology may be attained ; but its attainment would be pro tracted by the means which he points out. \6. He believes that Dr. Hutton's theory has been little noticed, not on account of of ts nature, but of its obscurity : he is however mistaken, for it is easily understood. 17- Cause of the neglect of Eacon among superficial naturalists.

IS. Bacon's design was not to erect the edifice of science, but only to lay its foundation on fixed principles. 19. The deficiency of his materials. 20. His opinion that facts ought to be exclusively the objects of attention. 21. All geological questions must be resolved hy facts. 22. The theory, distinctively called 11 uttoniun, connected with hypotheses common to many other theories. 23. Dr. Hutton and Mr. Playfair consider the alternate changes supposed in their theory, and the final causes which they assign to these changes, as reciprocally proving each other. 24. Outline of the llutto nian theory. 25. No limit assignable to the number of alternate changes supposed in it, from sea to land, and from land to sea ; whence all knowledge of a primitive state of ihe earth is placed beyond our reach. 26.

Aspect under which Mr. Pluv ial* presents his hypotheses. 2(i. a * The iear ot incurring the imputation of weakness may induce many to acquiesce in his theory, though they may not comprehend the ground of his confidence. 27- No other system could lead to the discussion of so many important geological questions. 28. The origin if the 'mineral strata one of the greatest objects of this science. 2y. Huttor.ian opinions respecting the degradation of our conti nents, and tlie action of external causes upon them. 30. Respect ing the sediments of rivers, andthe materials detached by the sea from \m coasts. 31. Whether our mineral strata could have been formed from the detritus of former continents. 31. a. Causo assigned by Dr. Hutton for the consolidations hose materials. 32. The birth of our continents produced by some great revolution upon our globe. 33.

Ruinous appearance of the mineral strata. 34. Either their mass must have been raised, or the level of the sea must have sunk. 35. Importance of ascertain ing the an/irjuity of our continents. 36. Necessity of properly classing the observations made in geological travels. 37. No inquiries made in early times respecting an antecedent state of * In the original there is ari -tcc'-dental repetition of thq numbers of some of the sections; a similar repetition has necessarily occurred in the translation, ia oder that the numbers may correspond. tho the earth. 38. Attention first attracted to this object by the marine shells found at a distance from the sea. 39. However erroneous the first theories of the earth may have been, they have yet served to accumulate materials, by which geology is now become a solid science. 40.

It is more fixed than is generally •supposed. 41. The confusion which has arisen in it can be dissipated only by more attentive study. 42. Distinction to be made between phenomena produced by causes stilt in action, and by such as have ceased to act. 43. The production of our continents to be ascribed to causes which have ceased to act, and the modification of their original state to causes still in action. 44. The original stale ot our continents, and likewise their age, determinable by the action of actual causes. 45. Their small antiquity already proved by Mr. De Luc, in his Lettres phys. et mor. sur i'Hist. de la Terre et de VHomme. 46. His answer to Dr. Schmieder's theory; and the difference between that and Dr. Hutton's. 47. The first point necessary to be fixed in geology is the state of our continents at their birth. 48.

Great importance of M. de Saus sure's observations on mountains. 49- The original and actual states of the strata composing mountains afford a clue to the know ledge of past events. 50. The Huttonian theory excludes granite, porphyry, &c. from the number of stratified substances. 51. The production of granite by chemical precipitations was the first operation of physical causes on our globe; other strata have been successively formed in the same manner: the catastrophes undergone by the whole mass of strata have produced the relative differences of level between mountains and plains. 52. Ne cessity of studying the effects formerly resulting from causes, which, though still existing, no longer produce such effects, on account of the change of circumstances. 53. Reference to Mr. De Luc's Lettres sur I'Hist. physique de la Terre, adressees a M. le Prof. Blumenbach. 54.

Nothing originally produced under the form of mountains. 55. The principal points of Mr. De Luc's Theory: I. Respecting the origin of our continents. II. Origin of our mountains and plains. III. Islands of the an cient sea, of which some sunk beneath the level of the waters, with all their animals and vegetables; IV. While others, not •submerged, became the summits of our present mountains, and ihe sources of vegetation for the new continents. V. Retreat of tU the sea from the new continents, to cover those ancient ones which sunk. VI. Permanence of level of the new 'sea. Vlf. Shortness of the time elapsed since the above revolution. 56. Nothing conjectural in this theory, facts being its only foundation. 57. The strata qf granite form the most ancient geological monument. 5S. Effects produced on the new continents by atmospherical causes. 59- The production of granite must have been a first operation, resulting from the accession of some new cause. 60.

How far Chemistry is useful in Geology. 6l. Liquidity being necessary to every chemical precipitation, the first change which took place in the mass containing the ingredients of granite consisted in its acquiring liquidity. 62. This liquidity could have been produced by the union of fire only with the molecules of the mass. 63. M. de la Metherie's misconcep tion of this point. 64. Water, ice, and aqueous vapour, are the three forms under which that substance now appears, which, previously to its union with the fire of liquefaction, could not be described by either of those terms. 6*5. In that elementary state, the particles of this substance were intermixed with all others; when united with fire, it forme-5 the primordial liquid, whence our mineral strata and the atmosphere were successively separated; and the waters of the present sea then remained as a residuum.' 66.

Fire being composed of light, and of another substance belonging to the atmosphere and to ter* restrial bodies, the latter, though intermixed with all other elementary particles, could produce neither heat nor liquidity, till it received the addition of light.- 66. cr.'The source of light beyond the reach of philosophical research. 67. The sea, having lost all the substances which produced our mineral strata, no such precipitations now take place in it; nor is the mass of the strata any longer subject to the catastrophes, by which their preceding revolutions had been occasioned. 68. Volcanos have not contributed to these effects in any way yet discovered. 69. The causes of the sutecssive differences of precipitations, .and of the subsequent catastrophes of the strata, must have been contained within the earth itself. 70.

Question whether the highest parts of the earth have been raised, or the lowest have subsided. 71. The existence of caverns a fixed point in Geology; but, according to the theory of subsidence, they have been .mostly fi lied up; according to that of elevation, they must stilj exist. exist. 72. The object of the following Dissertation will be -to examine how far the original state of each part of the surface of our continents can be determined by an investigation of the causes which have acted on them, and of the effects produced by those causes. DISSERTATION On the geological phenomena which determine the state of our continents at their birth. Preceded by some general remarks on the causes which retard decisions in the study of Nature; and containing an examination of Dr. Hutton's Theory of the Earth, § 73.

The state of our continents at their birth forms a central point, to which all observations of phenomena ought to tend. 74, 75. Necessity of studying the causes now in action 011 the continents, and determining what effects they have already produced. 76. The same phenomenon, accompanied by different circumstances, requires repeated observation. 77. The observation of phenomena in their various associations with each other, will enable us to ascend to their respective causes, which are all mutually connected by corresponding links. 78. Eager ness of the human mind to generalize phenomena, before it has sufficiently ascertained their distinctive characters. 79- The decomposition of phenomena recommended by Bacon. 80. Danger of generalizing complicated phenomena. 81. No conclusions relative to causes should be drawn, until the most remote have been studied no less carefully than the immediate, and until the circumstances have been distinguished by which the phenomena are connected with each other. 81. a. A previous assemblage of solid general principles leads to the only safe way in which conclusions may be formed. 82.

Generalizations, however just, bear no intrinsic characters of truth. 83, 84. Details of phe nomena arc therefore required, to furnish proofs of the truth of generalizations. 85. The state of our continents at their origin can be determined only by an investigation of the causes now operating, and of the changes already produced. 86". Con clusions drawn by Dr. Hutton from this mode of inquiry. 87. Mr. De Luc had formerly addressed four letters to Dr. Hutton 011 the subject of his theory. 88. These were little no ticed by that gentleman, and by Mr. Plavfair, probably because they they ehieflv contained generalizations os phenftmeM. S*9. ftf»« De Luc's Letters to Pros. Blumenbach, contain the exposition of the whole of his system. 90. Acquiescence of Messrs. de Dolomieu and de Saussure in his opinions respecting the small antiquity of our continents. 91, 92.

Little attention paid to his writings by Dr. Hutton and Mr. Playfair. 9*3- The above question must ultimately be decided by facts. 94- Mr. Playfair's opinion that the present line of our coasts, with their gulphs and promontories, has been formed by the action of the sea. 95. The tendency of that action is, on the contrary, to fill up gu/phs, and to destroy promontories, originally existing around our continents. £)6. Tho fragments of rock which fall from the cliff's, being impelled against them by the waves, form in time an elevated beach, at their foot: the action of the sea, therefore, could not have originally produced those cliffs, which, by this process, it tends to place beyond the reach of its waves. 97. Mr. Playfair's own description of the phenomena of low coasts proves that no action of the sea could have produced cliffs.

Thu gain of the land on the coasts is not wholly at the expense of the higher grounds, but results, in a great measure, from the sandof the sea itself. 97- *■**- The cascades falling down into the princu. pal •culky, and the semi-cones of rubbish formed under them against its sides, disprove Mr. Playfair's assertion that none of the lateral vallies join it at either too high or too low a level. 98, 99- Mr. Playfair infers the remote antiquity of our continents from successive platforms of alluvial land on the sides of vallies in which rivers flow. 100. Such platforms do not con sist of alluvial land. 101. Alluvial land is disposed in horizontal strata, of which the lowest always contain the largest materi als; but in these platforms, the strata are often inclined, and the gravel is most commonly above the sand. 102.

Operations of rivers in loose soils. 103. Rivers, which traverse their own alluvial land, run, in dry seasons, on a level lower than that of the adjacent grounds. 104. Those which run always lower, either on both sides, or on one only, have cut their channels in original soils; hence result three distinct cases: 1st, Where their action has gradually cut through an eminence composed of loose materials, round which they have not been able to wind. 105. 2dly, Where they have attacked and cut off a promontory in their way, forming it into an abrupt clif, while they have lest left a peculiar kind of alluvial land on the opposite side of their stream. 106. 3dly, Where their course has chanced to lie at the foot of an original cliff of loose materials; in which case there is no alluvial land on the opposite side. 106. a. In all these cases, the sections of the strata are shown on the banks, and may easily be distinguished from those of alluvial land. 107.

The dissimilarity of the strata on the opposite sides of rivers maintained in opposition to Mr. Playfair's assertion of their identity. 108. In what manner a lapidary would naturally reason, if informed of Mr. Playfair's comparison between the way in which a river had cut its course through a rock, and that in which he divides a block of marble with his saw. 109 110. What conclusions a lapidary, thus led to meditate, would probably draw respecting the disorder prevalent in the strata. Ill, 112. Inconsistency of ascribing the formation of loose strata to the rivers, and yet supposing those rivers to have sunk their beds in loose strata, when they first began to flow. 113, 114. Huttonian opinions relative to the migration of stones. 115. Lakes oppose a strong check to the system of the waste produced by running waters. 116 —120.

Mr, Playfair's account of the process by which lakes have been filled up, and cataracts effaced. 121. He speaks of the lake qf Geneva as forming an exception to other lakes. 122, 123. The law of changes applied in the Huttonian theory to an alternation of continents on this globe. 124. Mr. Playfair's "first attempt to account for the lake of Geneva, by supposing an uncertainty with regard to its original dimensions. 125. Those dimensions ascertained by a circumstance mentioned by himself. 126, 127- The furrows on the side of Mont Saleve, supposed by M. de Saussure to be traces of a current, are really effects of the partiad subsidences of separated masses of the strata, 128. Had the level of the lake ever stood as high as Mr. Playfair supposes, its dimensions would still have been too small to contain ttie sediments of the Rhone and its tributary streams, if the vallies ii> which they flow had really been excavated by them. 129- The pther phenomena of the tract of ground, which would then have formed its basin, disagree with Mr. Playfair's own account pf alluvial land. 130.

Mr. Playfair's second hypothesis of the production of this lake by the dissolution of a saline stratum. 131 —134. Ho\y far a Mr. Mr. Playfair adheres to the rules of philosophical investigation, which he particularly claims in this inquiry. 135 —137. No accurate judgment can be formed of the circumstances respecting the lake of Geneva, without a full consideration of that whole space, surrounded by mountains, of which it occupies only a part. Description, from M. de Saussure, of the defile of L'Ecluse. 13S. Of Mont Saleve. 139. Remarks on it. 140. Of Les Voirons. 141. Remarks on the difference between that mountain and Salete, 142. The original horizontally of Strata proved by the phenomenon of the breccias. 143 —145. Of the Rocks of Mcillerie, and the coast of the lake from Tour rondt to St. Gingough. !46, Of the rocks of St. Tryphon and Cham pigny, the mountains on the left bank of the Rhone and the lake, and the Val de Lie. 145. a. These descriptions clearly point out the true cause of the production of vallies and of the cavities of lakes, since they show the parts where fractures took place in the strata, and the different degrees of depression suffered by the separated masses. 146. a. The attention of geological observers ought to be particularly directed to these effects. 147".

Of the lakes of Jura. 148. Of the Dent de Vaulion. 149. Of the manner in which the above lakes are drained. 150. Of Val-orbe. 151 —157. Remarks and inferences. 158. Use of details concerning phenomena. M. de Saussure's description of the lakes of Neuchatel, Bienne, and Morat, 159. These three lakes were formerly united. 160 Evident marks of de pression in those spots. l6l. Remarkable situation of a consi*. derable mass of marie. 162. The dipping of the strata under the waters of the lakes points out where the masses sunk, by the depression of which those cavities were formed. 16*3. Of the lake of Annecy. 16*4. Additional details respecting tho mountains which surround it. l6'5. Les Bornes. 166. Valley between that mountain and Saleve. M. de Saussure's description of the Brezon. 167. Of the valley of Faucigny. 168.

A correspondence between salient and retreating angles is frequent in narrow vallies, which are commonly the effect of a single fracture; but not in large vallies, which are produced by two fractures, with a depression of the intermediate part. M. de Saussure's -description of the Monts Vergi. 168. a. Of the Mole, and of the mountains which follow it. 169. Of the Vallif Vallee du Reposoir. 170. Of the lake of Bourguet. 171. Deductions from the foregoing descriptions, that the lake us Geneva forms no exception to other lakes; that its cavity does not owe its production to any local cause, but to the same which produced all the basins of other lakes, and all vallies; and that the effects of that cause are plainly visible in the surrounding scenery. 172. That cause acknowledged by Mr. Playfair, unconnected as it is with his other hypotheses: his opinions respecting partial elevations and depressions. 173.

Concerning the phenomena of shifts in mines. 174. Concerning the angular motion of the strata, and the supposed existence of an expanding power, directed from the centre toward the circumference. 174. a. The angular movements of the strata will afford a fair criterion of the two opposite theories of subsidence and elevation. 175. The masses, which form our mountains, could not have undergone those motions, unless, by the subsidence of other masses, and the consequent production of vallies, spaces had been afforded them in which they could freely turn. 176. Mr. Playfair's statement of the Huttonian theory with respect to the expanding power of heat. 177, 178. He considers as separately demon strated the two propositions on which it rests; viz. the elevation of our continents from the buttom of the sea, and the consolidation, by heat, of the mineral strata. 179- Examination of the probability of the existence of such a power, and of the mode of its action. 180.

Mr. Playfair deduces its existence from the impossibility that any other power but that of fusion could have consolidated the materials of destroyed continents at the bottom of the sea. 181. The power of fusion is not, however, a power of elevation; the. intermediate idea of expansion is wanting. Not heat itself, but only an expansible fiuid produced by heat, could have power, by its density, to elevate the mass of our continents; and no sooner should that mass be fractured, than the fluid would escape through the openings, and the mass would sink down again in ruins. 182. Mr. Playfair provides against this objection, by supposing the breaches and separations in the strata to be completely JiY/fd up by wist ratified minerals. 183. Ne cessity of therefore examining whether these breaches are actually filled up. 184 —186'.

Metallic veins considered with this ■yiew: their contents shown to be stratified. 187- Little importa 2 ance XX ance of closing these passages, since the subsequent formation of caverns must have supplied so many others for the escape of the expansible fluid. 188. Basaltes and whinstone, having un dergone the same catastrophes as the other strata, cannot be considered as instruments in those very catastrophes. 189, 190. The supposition that the materials for one set of continents are supplied by the waste of another, and carried down by running waters to the sea, is refuted by the impossibility that such sub stances, necessarily intermingled confusedly with eachother, should in the sea, be separated according to their respective genera and species, and laid over its bed in distinct strata. 191.

Proofs of the non-existence of a great internal heat of the globe, from the remains of marine animals found in our continents, and from the intermixture of loose with stony strata. 193. System of chemical precipitations. 194*- Since our mineral strata were certainly formed at the bottom of the ancient sea, their materials must either have proceeded from the lands which surrounded it, or have been separated from the liquid which composed it. Per emptory exclusion of the first of these propositions. 195. Esta blishment of the second. 196". The elementary ingredients of th-p primordial liquid being now dispersed in combinations which are but imperfectly known to us, we cannot ascend to the primor dial operations by specific eiffinities. 197. Impossibility of recom posing mineral substances with the coercible ingredients furnished by our analyses. 198.

The greatest part ofthe ingredients, now composing the known substances of our globe, were contained in the primordial liquid, and separated from it by successive precipitations, produced by the ascent of new ingredients, and the escape of those expansible fluids by which our atmosphere was formed. 199- Dr. Hutton's exposition of his hypothesis respecting the expansive power of heat. 200. He considers this power as exercised by an expansible fluid, which he calls fiery vapour. 201. He deduces the first proof of his theory from the situation of volcanoes on the highest mountains. 202. The se cond, from lavas found among the strata of the earth. 203. Ac count of the elevation of the new island, near Santorini. 204, 205. Want of analogy between this volcanic operation, and the supposed elevation of our mineral strata. 206 — 208.