LOWER GREENSAND. 



27 



obliquely upwards." Pinna occurs also in clusters. The promi- 

 nence formed by this rock will be found at the foot of the cliiF, 

 600 yards east of the Coastguard Station. 



Fig. 10. 

 Panopcea plicata, Sow. 



The overlying set of beds (forming the upper part of Fitton's 

 Crackers Group, Nos. 6-10) embraces a thickness of about 40 

 feet. It consists of brown clay, 16 cr 17 feet thick, in the lower 

 part, and of clay mixed with sand in the upper part. The beds 

 are fossiliferous throughout, and are known as the Upper Lobster 

 Beds, from the occurrence in them of remains of Meyeria {Astacus) 

 vectensis. 



Fig. 11. 

 Gervillia anceps, Desh. 



Group IV., or the Lower Gryphasa [Exogyra] Group of Fitton, 

 hns at its base a bed of rust-coloured sand about 21 feet thick. 

 This is overlain by two feet of sand containing Gervillia (Perna) 

 alcpformis, but chiefly remarkable for the great abundance of 

 Terebratiila sella, Soav., which, though ranging Irom the base of 

 the Lower Greensand to the top of the Ferruginous Sands 

 (Group XIV. of Fitton), is nowhere so numerous as here. 



