THEORY of the EARTH. 219 



after the ocean was inhabited by thofe animals, which are pro- 

 per to that fluid medium. If, therefore, we knew the natural 

 hiftory of thofe folid parts, and could trace the operations of 

 the globe, by which they had been formed, we would have 

 fome means for computing the time through which thofe fpecies 

 of animals have continued to live. But how {hall we defcribe 

 a procefs which nobody lias feen performed, and of which no 

 written hiftory gives any account ? This is only to be invefti- 

 gated, jirft, in examining the nature of thofe folid bodies, the 

 hiftory of which we want to know ; and, zdly. In examining 

 the natural operations of the globe, in order to fee if there now 

 actually exift fuch operations, as, from the nature of the folid 

 bodies, appear to have been neceflary to their formation. 



BUT, before entering more particularly into thofe points of 

 difcuffion, by which the. queftion is to be refolved, let us take 

 a general view of the fubject, in order to fee what it is which 

 fcience and obfervation muft decide. 



IN all the regions of the globe, immenfe mafTes are found, 

 which, though at prefent in the mod folid ftate, appear to have 

 been formed by the collection of the calcareous exuvice of ma- 

 rine animals. The queftion at prefent is not, in what manner 

 thofe collections of calcareous relics have become a perfect folid 

 body, and have been changed from an animal to a mineral fub- 

 ftance ; for this is a fubject that will be afterwards conlidered ; 

 we are now only enquiring, if fuch is truly the origin of thofe 

 mineral mafles. 



THAT all the maffes of marble or limeftone are compofed 

 of the calcareous matter of marine bodies, may be concluded 

 from the following facts : 



iy?, THERE are few beds of marble or limeftone, in which 

 may not be found fome of thofe objects which indicate the 

 marine origin of the mafs. If, for example, in a mafs of 

 marble, taken from a quarry upon the top of the Alps or 



E e 2 Andes, 



