OSTREA. 



353 





i 



Figs. 123-134. — Ostrea diluviana, L123, zone of Schlanbachia rostrata, Devizes. Museum of Practical 

 Geology, No. 25820. Right valve. 124, 125, Upper Greensand, Sidmouth. British Museum, L3326. 

 Left valve. 126-130, Chalk Marl, Folkestone. Sedgwick Museum. 126, anterior view. 128-130, 

 right valves. 127, anterior view of 128. 131-133, Base of Chalk Marl, Haslingfield. Sedgwick 

 Museum. Bight valves. 134, Cenomanian Sandstone, Wilmington. Sedgwick Museum. Vertical 

 section of left valve. All x s.. 



