376 



Observalio7is on the Diluvial Gravel 



76 77 



species of shells that I have found in the ironstone of this 

 gravel are as small as the drawing represents them. 



Fig, 78. Encrinital remains or casts of E'ntrochi in chert, 

 vulgarly called screwstone, of which there are large quantities 



in this gravel. 



Fig. 79. A shell of the Pecten species, in a hard siliceous 

 pebble. Another specimen I have found also in flint, together 

 with the impressions of Echini and small Terrebratulae. 



Fig, 80. Caryophyllia, embedded in a similar kind of stone 

 ^ojg. 78. 



Fig. 81. A shell in a brown ferruginous sandstone, mixed 

 with several species of Terrebratulae and corallines. 



