250 Analylkal Notices of Books. 



state, both living and fossil, and fossil alone; and pointing out the 

 strata in which the fossils are met with, whether anterior to chalk, 

 in chalk, or posterior to it. Other columns enumerate the num- 

 ber of living, aiid of fossil species, respectively, of each genus ; 

 and notices are appended where any of these are either identical, 

 analogous, or subanalogous. In the Vertebrata, only those genera 

 are referred to which contain fossil species; and the same plan is 

 pursued in Insects and in Vegetables. From these tables many 

 curious results may be deduced, as well with respect to the rela- 

 tive proportion of the number of fossil to that of living species, 

 as to that which exists between the remains of various families to 

 be met with in the different strata. Thus of Mammalia, none 

 have yet been discovered except in formations later than chalk ; 

 while Reptiles and Fish are found not only in these, but also in 

 chalk, and in strata anterior to it. The number of species of 

 shells existing in the living state is enumerated at 3080, while 

 that of the fossil ones amounts to 2776 ; 64 of which only are 

 referred to as identical, and 236 as analogous. The number of 

 living univalves exceeds considerably that of the fossil, and these 

 are chiefly to be met with in the later formations ; a disposition 

 which is reversed in the bivalves, where the fossil species are in 

 greater number than the living, and a very large proportion are 

 found in the earlier strata. These are also numerous in the chalk 

 formations, which contain species of 25 genera of bivalves ; while 

 only four species of univalves have hitherto been discovered in 

 them ; a discrepancy which seems worthy of particular remark. 



To enter at any length into the numerous other points comprised 

 in this very interesting publication, would lead us into a detail 

 unfitted for our more immediate province. Enough however has 

 boon stilted in touching even thus slightly on a few of them, to 

 induce all who feel an interest in its subject to desire a more inti- 

 mate acquaintance with its contents. To say that these are 

 worthy of the pen of its enlightened author, is at once to charac- 

 terize them suiiicicntly. 



