THEORY OF THE EARTH. 19 



x" 



Foliated rocks rest upon its sides, and form the 

 lateral ridges of these great chains ; schists, por- 

 phyries, sandstones, and talcose rocks, intermingle 

 with their strata ; lastly, granular marhles, and 

 other limestones destitute of shells, resting upon 

 the schists, form the outer ridges, the lower steps 

 as it were, the counterforts, of these chains, and 

 are the last formations, by which this unknown 

 fluid, this sea without inhabitants, would seem to 

 have prepared materials for the mollusca and zo- 

 ophytes, which were presently to deposite upon 

 these foundations vast heaps of their shells and 

 corals. 



We even find the first productions of these 

 mollusca and zoophytes appearing in small num- 

 bers, and scattered at greater or less distances, 

 in the last strata of these primitive formations, or 

 in that portion of the crust of the globe to which 

 geologists have given the name of Transition rocks. 

 Here and there we meet with beds containing 

 shells, interposed between certain granites of later 



materials of which the globe is composed, have perhaps ex- 

 isted at first in the elastic form, and have successively as- 

 sumed a liquid consistence on cooling, and have at length 

 been solidified, is well supported by the recent experiments 

 of M. Mitscherlich,, who has composed, of all sorts of sub- 

 stances, and crystallized by the heat of intense furnaces, se- 

 veral of the mineral species which enter into the composi- 

 tion of primitive mountains. Note D. 



B 2 



