LAMARCK'S WORK JN GEOLOGY 121 



mountains, which are generally arranged in more or 

 less regular chains. But he strangely assumes that 

 the constituents of granite, i.e., felspar, quartz, and 

 mica, did not exist before vegetables, and that these 

 minerals and their aggregation into granite were the 

 result of slow deposition in the ocean.* He goes so far 

 as to assert that the porphyritic rocks were not thus 

 formed in the sea, but that they are the result of depos- 

 its carried down by streams, especially torrents flowing 

 down from mountains. Gneiss, he thinks, resulted from 

 the detritus of granitic rocks, by means of an inappre- 

 ciable cement, and formed in a way analogous to that 

 of the porphyries. 



Then he attacks the notion of Leibnitz of a liquid 

 globe, in which all mineral substances were precipitated 

 tumultuously, replacing this idea by his chemical no- 

 tion of the origin of the crystalline and volcanic rocks. 



He is on firmer ground in explaining the origin of 

 chalk and clay, for the rocks of the region about Paris, 

 with which he was familiar, are sedimentary and largely 

 of organic origin. 



In the "Addition "(pp. 173-188) following the fourth 

 chapter Lamarck states that, allowing for the varia- 

 tions in the intensity of the cause of elevation of the 

 land as the result of the accumulations of organic 



* Cuvier, in a footnote to his Discours (sixth edition, p. 49), in 

 referring to this view, states that it originated with Rodig {La Physique, 

 p. 106, Leipzig, 1801) and De Maillet {Telliamed, tome ii, p. 169), 

 "alsoaninfinity of new German works." He adds : "M. de Lamarcli 

 has recently expanded this system in France at great length in his 

 HydrogMogie and in his Philosophic zoologique." Is the Rodig re- 

 ferred to 111. Chr. Rodig, author of Beitrdge ziir Naturwissenschaft 

 (Leipzig, 1803. 8°)? We have been unable to discover this view in De 

 Maillet ; Cuvier's reference to p. 169 is certainly incorrect, as quite a 

 different subject is there discussed. 



