LAMARCK'S WORK IN GEOLOGY 



103 



detritus of organic bodies successively accumulated, 

 which perpetually elevates, although with extreme 

 slowness, the soil of the dry portions of the globe, 

 and which does it all the more rapidly, as the situa- 

 tion of these parts gives less play to the degradation 

 of the surface caused by the rivers. 



" Doubtless a plain which is destined some day to 

 furnish the mountains which the rivers will carve out 

 from its mass would have, when still but a little way 

 from the sea, but a moderate elevation above its river 

 channels ; but gradually as the ocean basin removed 

 from this plain, this basin constantly sinking down 

 into the interior {e'paisseur) of the external crust of 

 the globe, and the soil of the plain perpetually rising 

 higher from the deposition of the detritus of organic 

 bodies, it results that, after ages of elevation of the 

 plain in question, it would be in the end sufficiently 

 thick for high mountains to be shaped and carved 

 out of its mass. 



"Although the ephemeral length of hfe of man 

 prevents his appreciation of this fact, it is certain 

 that the soil of a plain unceasingly acquires a real in- 

 crease in its elevation in proportion as it is covered 

 with different plants and animals. Indeed the debris 

 successively, heaped up for numerous generations of 

 all these beings which have by turns perished, and 

 which, as the result of the action of their organs, 

 have, during the course of this life, given rise to 

 combinations which would never have existed with- 

 out this means, most of the principles which have 

 formed them not being borrowed from the soil ; this 

 ddbris, I say, wasting successively on the soil of the 

 plain in question, gradually increases the thickness 

 of its external bed, multiplies there the mineral mat- 

 ters of all kinds and gradually elevatesthe formation." 



Our author, as is evident, had no conception, nor 

 had any one ' else at the time he wrote, of the slow 



