of Zoological Characters in Geology. 239 



surface of the globe certainly belongs to the same geological 

 epoch, which commenced at the moment our continents 

 took their present forms ; and although this epoch does not 

 furnish instances of geological phenomena on a grand scale, 

 and we meet m ith but few cases of the formation of new 

 rocksj yet they are sufficient to shew us, for example, that 

 the argillo-trap rocks formed by Vesuvius, and most of our 

 volcanoes, the calcareous rocks formed by many of our 

 springs, and the siliceous rocks formed by some others, (those 

 of Iceland, &c.), are mineralogically very different from 

 each other ; but that the organic remains they envelope have 

 all the common character of the generation established on 

 the earth since the commencement of this epoch. 



It is not the same with respect to the generations of or- 

 ganized beings : they may be destroyed in an instant; but 

 it certainly requires considerable time to recreate them so 

 that they be developed in the number and variety in which 

 they are usually presented to us. This developement sup- 

 poses a long series of ages or at least years, which establish 

 a true geological epoch, during which all the organized 

 bodies which inhabit, if not the whole surface of the globe, 

 at least very extensive parts of that surface, have acquired a 

 certain character of family or epoch, which cannot be de- 

 fined, but which cannot be misunderstood. 



I then consider the characters of tlie epoch of formation 

 drawn from the analogy of organized bodies as of the first 

 importance in geology, and as superior to all other differ- 

 ences, however great they may appear. 



Thus when the characters derived from the nature of the 

 rocks, and what is of least value, of the height of the rocks, 

 of the formation of the valleys, even the dip of the beds and 

 the greatest non-comformable stratification, are opposed to 

 that which we derive from organic remains, I should still 

 give the preponderance to the latter ; — for all these circum- 

 stances, all these differences may result from an instanta- 

 neous revolution or formation, which does not, in geology, 

 establish a special epoch. Without endeavouring to prove 



I 



