It was, of course, too early in the history of geology for Lamarck to seize hold of the fact, now so well known, that the highest mountain ranges, as the Alps, Pyrenees, the Caucasus, Atlas ranges, and the Mountains of the Moon (he does not mention the Himalayas) are the youngest, and that the lowest mountains, especially those in the more northern parts of the continents, are but the roots or remains of what were originally lofty mountain ranges. His idea, on the contrary, was, that the high mountain chains above mentioned were the remains of ancient equatorial elevations, which the fresh waters, for an enormous multitude of ages, were in the process of progressively eroding and wearing down. What he says of the formation of coal is noteworthy: "Wherever there are masses of fossil wood buried in the earth, the enormous subterranean beds of coal that are met with in different countries, these are the witnesses of ancient encroachments of the sea, over a country covered with forests; it has overturned them, buried them in deposits of clay, and then after a time has withdrawn." In the appendix he briefly rehearses the laws of evolution as stated in his opening lecture of his course given in the year IX. (1801), and which would be the subject of his projected work, _Biologie_, the third and last part of the Terrestrial Physics, a work which was not published, but which was probably comprised in his _Philosophie zoologique_. The _Hydrogéologie_ closes with a "_Mémoire sur la matière du feu_" and one "_sur la matière du son_," both being reprinted from the _Journal de Physique_. FOOTNOTES: [60] _Evolution in Biology_, in _Darwiniana_, New York, 1896, p. 212. [61] _Principles of Geology_. [62] Lyell's _Principles of Geology_, 8th edit., p. 22. [63] Quoted from Flourens' _Éloge Historique de Georges Cuvier_, Hoefer's edition. Paris, 1854. [64] _Remarques sur les Coquilles fossiles de quelques Cantons de la Touraine_. Mém. Acad. Sc. Paris, 1720, pp. 400-417. [65] _Éloge Historique de Werner_, p. 113. [66] _History of Civilization_, i. p. 627. [67] _France under Louis XV._, p. 359. [68] _France under Louis XV._, p. 360. [69] See vol. iii. of his _Mémoires sur differentes Parties des Sciences et des Arts_, pp. 209-403. Geikie does not give the date of the third volume of his work, but it was apparently about 1771, as vol. ii. was published in 1770. I copy Geikie's account of Guettard's observations often in his own words. [70] Lyell's _Principles of Geology_. [71] Geikie states that the doctrine of the origin of valleys by the erosive action of the streams which flow through them, though it has been credited to various writers, was first clearly taught from actual concrete examples by Desmarest. _L. c._, p. 65. [72] Jameson's _Cuvier's Theory of the Earth_, New York, 1818.