XIX. LETTER The advocates of this imagination feel, that no moderate sequence of time would accomplish such wonderful mutations as these, and therefore stretch their chronology to an almost endless period, in order to allow a duration long enough for the production of such an effect: as if any succession of years could effect that, which never can be achieved but by the Omnipotence which they disclaim or supersede. The answer to such dreams is given conclusively by Baron Cuvier's brother; that there never has been an instance of such a change, and therefore it is a lawless conjecture, formed in wilful contradiction to all recorded knowlege, and to all existing experience.27 It is on the fossil remains and the succession of plants, and of the small marine animals, and of interposed strata, and of apparent successions of fresh still maintained by his followers. M. F. Cuvier thus briefly states them as now upheld by some. The theory of Buffon supposed living organic molecules, which becoming developed, each according to conditions peculiar to it, after the lapse of thousands upon thousands of years, are themselves modified into as many myriads of times, and have, at last, been brought into that state, in which they were able to produce this world of living animals which now covers the surface of our globe, from the creatures that can be only rendered visible by the aid of the microscope.' F. Cuvier's Prelim. Disc. to Baron Cuvier's Fossil Bones. 4 Ed. Lond. v. i. p. 7. 27The truth really is this: There is no fact whatever, of this description, amongst the records of science. For, no person in the world has ever seen any species transform its state of existence, to any extent or in any shape, in order to be converted, either totally, or even partially, into another species.' Prel. Dis. p. 8.— Neither has there been a single case known, throughout the world, in which one of our dogs has been found turned into a wolf, or a jackal, or a fox. There is no example in the records of natural history of a horse having assumed the character of an ass; or an ass taking on those of a zebra. Never did we find a single instance, in which any one variety of our goats was metamorphosed into sheep, or vice versa.' Ib. p. 10. XIX. water and sea water overfloodings in some particular LETTER parts, as in the chalk or calcareous basins or formations of France and England, that many have raised up an anti-Mosaic chronology. The limits and remaining topics of this work, will not allow me to go into that detail of facts and reasonings, which satisfy me, that erroneous conclusions have been formed on these points from insufficient and sometimes misapprehended premises. But I am convinced, after a deliberate judgment, that in opposing the authentic facts of revelation, they are consigning themselves to future censure and neglect. It was an old Roman remark, that What is true, time confirms, and obliterates what is otherwise. It has already brought to light many phenomena which have thrown down several former fallacies; it will yet disclose others to us, which will subvert all the newer mistakes, that are now so strongly maintained. The fossil remains recently discovered in the Burdiehouse Limestone, near Edinburgh, alluded to in the preceding Letter, 28 are a proof that some of our present geological theories must be greatly modified, as a larger examination of nature reveals more fully our Creator's subterraneous operations to us." 28 See page 349. Note 21, of Letter 18. 29 29 Dr. Roget at the close of his late valuable work, justly says, The pursuit of remote and often fanciful analogies has, by many of the continental physiologists, been carried to an unwarrantable and extravagant length: for the scope which is given to the imagination in these seductive speculations, tends rather to obstruct than to advance the progress of real knowlege. By confining our inquiries to more legitimate objects, we shall avoid the delusion, into which one of the disciples of this transcendental school appears to have fallen, when he announces with exultation, that the simple laws he has discovered have now explained the universe: nor shall we be disposed to lend a more patient car to the more presumptuous reveries of another systembuilder, BB 3 XIX. LETTER builder, who, by assuming that there exists in organized matter an inherent tendency to perfectibility, fancies that he can supersede the operations of Divine agency.' Dr. Roget closes his gratifying task with this admirable paragraph. Happily there has been vouchsafed to us, from a higher source, a pure and heavenly light to guide our faultering steps, and animate our fainting spirit, in this dark and dreary search, revealing those truths which it imports us most of all to know; giving to morality higher sanctions; elevating our hopes and affections to nobler objects than belong to earth, and inspiring more exalted themes of thanksgiving and of praise.' Roget, An. & Veg. Phy. vol. ii. p. 639-41. LETTER XX. NEW FORMATION OR ADJUSTMENT OF THE SURFACE, AFTER MY DEAR SYDNEY, THAT the present surface of the earth on which we are living, was not, in all its regions, that primeval surface on which the first plants vegetated, the organic remains in several of the subterraneous rocks satisfactorily evince. The exterior masses of our globe, to the lowest depth that we have been able to explore, appear to consist of a succession of rocks, which have been traced and named, and of which you had a summary notice in the 7th and 18th of my former Letters, with a brief intimation of the vegetable and animal fossils which had been found among them. It would be too great a digression from the main and chosen subject of the present correspondence to enter into a review of the geological construction of our earth, altho it is an important compartment of its sacred history. But my other topics, and the limits which I have fixed for these pages, compel me to abstain from it, and only to desire you to bear in mind that the rocks and strata which we have attained to know, are distinguishable by a natural separation into two great divisions. Those which, containing no organic remains, give thereby evidence, that they were formed and laid down before plants and animals were created; and those which, LETTER XX. XX. LETTER containing in several of their series and localities, fossil remains of organic life, must have been made and deposited at a subsequent period. The first are called the primordial or primary rocks, of which the chief members are granite, gneiss and mica slate; to which some minor and subordinate ones are in several places attached. These primordial rocks constitute the greatest bulk of our surface masses. The Granite formation appearing every where, and often uncovered by others, presents to us many indications that it is the foundation rock, on which all the others have been placed; and that it encompasses the whole circuit of the globe. Not so universal as this, but the next to it in extent and lying upon it, are the Gneiss rocks, which, in several countries predominate on the visible surface; and still less general, yet more so than any other, the Mica slate formation appears resting upon the gneiss, where that has preceded it, or on the granite, where no gneiss has been deposited. Upon these have been placed those which have been called transition, and intermediate, in their lower masses; and secondary in the upper ones; but to all of which we may apply the term Secondary, to distinguish them from a later series, which have been termed tertiary and diluvial. They comprise principally the slate formations, the grauwacke, and old and new red sandstones; the mountain and magnesian limestones; the oolites and lias, up to the great chalk beds, with some others less remarkable. On these, the tertiary and diluvial strata have been deposited, which are more immediately connected with the Deluge, as it is in some of these, always nearest the present surface, that the fossil |