THE CRUST OF THE EARTH. 



Even in this list, extensive as it is, numerous strata in which 

 animal remains largely predominate, have been omitted. In the 

 tertiary and more recent deposits, every order of existing 

 animated nature is found. The bones of man, however, are 

 confined to the superficial part, which has been formed since the 

 globe was peopled by the races which now inhabit it. 



76. How completely changed the inhabitants of the earth have 

 been from one geological period to another, may be inferred from 

 the following observations of Sir R. Murchison. " Beginning," 

 says he, "with the vertebrata, are not the fishes of the old red 

 sandstone as distinct from those of the carboniferous system, on 

 the one hand, as from those of the Silurian on the other ? M. 

 Agassiz has pronounced that they are so. Are any of the crus- 

 taceans, so numerous and well defined throughout the Silurian 

 rocks, found also in the carboniferous strata ? I venture to reply, 

 not one. Are not the remarkable Cephalopodus mollusca, the 

 Phragmoceras, and certain forms of Lituites, peculiar to the older 

 Silurian system ? Is there one species of the Crinoidea figured, 

 known in the carboniferous strata ? Has the Serpuloides longis- 

 simus, or have those singular bodies the Graptolites, or, in 

 short, any zoophytes of the Silurian system been detected in 

 the well-examined carboniferous rocks? And in regard to 

 the corals, which are so abundant, that they absolutely form 

 large reefs, is not Mr. Lonsdale, who has assiduously com- 

 pared multitudes of specimens from both systems, of opinion, 

 that there is not more than one species common to the two 

 epochs ? " 

 70 



