460 FOSSIL INVERTEBRATED ANIMALS. 



We can clearly recognize the identity of some fossil species 

 with the living : in other cases, we only find an analogy ; and 

 there are some in which the relations are much more remote. 

 These three different states, or circumstances, are well expressed 

 by M. de France, in the terms identical, analogous^ subana- 

 logons. 



With the exception of a trochus, and two or three species of 

 terebratulites, which are derived from strata anterior to the 

 chalk, and which have some analogy with species now existing, 

 — and, again, of one species of the last-mentioned genus, found 

 in the chalk, and which appears to be identical with terebratula 

 vitretty it is only in the strata more recent than the chalk that 

 identity or analogy can be observed. 



It is very remarkable that the greatest number of identical 

 or analogous species are found in the strata of the Placentine, 

 and of Italy generally — for, to two hundred and forty there are 

 one hundred and sixty in this predicament ; and of these, one 

 hundred and thirty-nine have been marked as identical by M. 

 Brocchi. It is possible that this distinguished naturalist may 

 have a little overrated the number, or not placed the strictest 

 bounds between identity and analogy. 



The upper marine sandstone formation, of the neighbourhood 

 of Paris, appears to contain a less number of marine fossil 

 bodies than that of the coarse limestone ; although some species 

 are found in the first which are not to be met with in the other. 

 Some, from both formations, appear to be identical. But the 

 most part, very nearly the whole, present nothing more than 

 analogy; for out of fifty species from the upper sandstone, 

 M. de France found but three which perfectly resemble those 

 of the coarse limestone. In the latter, some species are larger 

 and others smaller than in the former ; which is the case with 

 other different species in the sandstone. In fine, some species, 

 which are very common in the coarse limestone, are very rarely 

 found in the upper marine sandstone. 



The bulbiform fusus, which is found at Grignon, appears to 



