Miscellaneous InteUiyence. 87 



British Fossil Shells.— The. following series of fossil shells are known to 

 English naturalists:— 



Simple univalves 58 genera, which comprise 401 species. 



Simple bivalves 62 583 



Complicated bivalves 3 51 



Multilocular bivalves 12 230 



135 1265 



On making three principal divisions of the formations containing organic 

 remains, and enumerating the shells they respectively contain, we have 

 these results : 



The first, which is also the lowest or most ancient division, may be sub- 

 divided into two series of formations. 



1. Carboniferous order 2. From the carboniferous 



of Mr. Conybeare. to the lias, inclusive. 



Species 27 Simple univalves - - - - 9 species. 



34 Simple bivalves - - - - 33 



46 Complicated bivalves - - 5 



33 Multilocular univalves - - 50 



140 97 



The second, or middle division, 

 from the lias upwards, includes the 

 entire oolite series, and the strata up 

 to the chalk, inclusive. 

 Simple univalves 106 species. 



Simple bivalves 375 



Complicated bivalves 

 Multilocular univalves 139 



620 



The third, or most recent, divi- 

 sion, comprises all the beds above 

 the chalk, or the tertiary forma- 

 tions. 



Simple univalves 



Simple bivalves 



Complicated bivalves 



Multilocular univalves 



408 



The numbers of each of the four classes of shells which existed during 

 seperate periods or geological intervals, are as follows: 



Second and Third Divisions. 

 First Division. Remaining strata, above the 



Ancient strata, including lias. lias, up to diluvium. 



Species 36 Simple univalves - - - - 365 species. 

 67 Simple bivalves - - - - 516 

 1 o 1 <51 Complicated bivalves - - 0>,._ 

 1J4 £83 Multilocular univalves - - 147 S 



237 1028 



Mr. Taylor next illustrates from the Tables, Mr. Dillwyn's remarks on 

 the distribution of carnivorous and herbivorous Trachelipodes. He shows 

 that, in the English formations, the Zoophages comprise 22 genera, and 171 

 species. They may be considered as appertaining to, if not as wholly cha- 

 racteristic of the tertiary formations ; and many of the genera are continued 

 in our present seas. Of the Phyllipharjes, 22 genera and 168 species are 

 distributed through the secondary and tertiary formations. 



When the members of each of these classes are arranged according to the 

 three geological divisions already mentioned, we find that the turbinated 

 univalves of the older strata or rocks belong almost entirely to the herbi- 

 vorous family, 12 genera having originated there, which have been per- 

 petuated through all the successive strata, and still inhabit our waters; that 

 in the middle series of formations, this preponderance of animals possessing 

 similar habits was preserved ; and that, in the last series, after the chalk 

 was deposited, this order was suddenly reversed, in the proportion of 5 

 to 19. 



Mr. Dillwyn observed that all the marine Trachelipodes, of the herbi- 

 vorous tribes, in the ancient strata, are furnished with an operculum, 

 seemingly intended as a protection against the Cepbalopodes, or carnivorous 

 order of Nautili, Ammonites, &c, which, at that time, abounded in the 

 - After the epoch of the extinction of this order (which terminated 

 chiefly with the chalk), numerous unoperculated genera appear, as if no 



