A. 8f R. Bell — On the English Crags. 



257 



graphical considerations render an alteration imperative. In the two 

 latter instances the names are very inappropriate : Eed, because all 

 gradations of colours may be noticed, and the colour is not peculiar 

 to this deposit; the Norwich, or Fluvio-marine, because the formation 

 extends beyond the confines of Norfolk, and is in many places ex- 

 clusively marine. 



The horizons proposed for adoption stand thus : — 

 The Pre-glacial, or Chillesford series, comprising the Chillesford 

 sands and clays,, the Forest Bed, and all deposits intervening 

 between the Upper Crag and the Lower Glacial beds. 

 The Upper Crag :^ the Norwich Fluvio-marine, and the upper part of 



the Suffolk Eed Crag (as hereafter indicated). 

 The Middle Crag := the Eed Crag proper. 

 The Lower Crag = the Coralline Crag. 



Our calculations have been chiefly based upon the MoUusca, these 

 only having yielded sufficient results for comparison; but as no 

 table has been published of the organic remains known to exist in 

 each of the Crags, we present the nett total of each group of which 

 we have lists. 



SUMMARY. 



o 



1 



a3 





1 



u 



Ph 



It 





Cetacea 



2 



1 



9 



9 



21 

 10 



4 

 17 



193 



14 



1 

 169 



6 

 125 



4 



1 

 88 



2 



675 



21 

 14 



3 



2 



4 



8 



1 

 11 



5 

 178 



5 



135 



1 

 30 



5 



2 

 26 



1 



2 



1 



3 

 2 

 2 

 9 

 108 

 3 



74 

 2 

 5 

 2 



6 



1 

 2 



3 



22 

 64 

 4 



71 

 2 



10 



3 



23 



6 



1 



3 



1 



3 



19 

 46 



3 



73 

 3 



5 

 12 



Other Mammalia 



Aves 



Pisces 



Insecta 



Crustacea ■, 



Ostracoda 



Cirripedia 



Annelida » 



Echinodermata 



Land and Freshwater MoUusca 



Marine Gasteropoda and Solenoconcha. 

 Opisthobranchiata 



Pteropoda 



Laraellibranchiata 



Brachiopoda 



Polyzoa 



Ccelenterata 



Protozoa 



E,hizopoda 



Plantse 



Total in each formation 



452 



213 



185 



200 



With reference to the much vexed question of species or varieties, 

 we are of opinion that a well-defined variety, one easily recognizable, 

 and accepted as a distinct species by the majority of naturalists, or 

 even one that is the characteristic form in other seas or formations. 



VOL. VIII. — NO. LXXXIV. 



17 



