RECENT DEPOSITS OF NERBUDDA VALLEY. 285 



Paludina melanostoma. B. Not uncommon. 



This shell is not easily separable in a fossil state from the smaller 

 varieties of the last. It is stouter and rounder in the whorls than 

 is generally the case with P. Bengalensis. 

 Bithinia cerameopoma B. Not rare. 

 Bithinia pulchella B. Not rare. 



Helicidse. 

 Bulimus insidaris Eh. (B, pullus, Gray). Rare. 

 Occasionally met with in the reddish clay, 



Limnseidse. 

 Limncea sp. Not common. 



A small pointed shell of the type of L. acuminata. Desh. 

 Planorbis Coromandelicus Fab. Very rare. 



But ona or two specimens noticed. 

 Planorbis convexiusculus B. Rare. 



CONCHIFERA. 



Unionidse. 

 Unio marginalis Lam. Common. 



This shell occurs very fine, chiefly in the clay. 

 Unio corrugatus Lam. Common. 

 This shell is very abundant and fine: it exhibits a marked variety 

 with a greater transverse breadth across the umbones, which gives 

 it a more triangular appearance than the normal shell. The same 

 variety also exists with the ordinary form in the Nerbudda at present. 

 Unio cceruhus, Lea. Common. 

 This shell often occurs extremely fine in the clay, while in the gra- 

 velly beds a dwarfed variety is met with not more than half the 

 size of specimens from the clay. 



Cycladidse. 

 Corbicula cor. Sow. Very common. 

 Two varieties of this shell occur commonly. One, the usual form, 



