76 CRETACEOUS ROCKS OF S. INDIA. [PaRT II. ^ 1. 



have mentioned in the introductory chapter, Mr. Cunhfife's second col- 

 lection, which consisted solely of Ootatoor fossils^ still remains for descrip- 

 tion in the Museum at Calcutta. The fauna is, however, exceedingly 

 rich, and is of especial interest as being intermediate in age between the 

 Neocomian fauna of the Valudayur beds of Pondicherry, and that of the 

 newer deposits in Trichinopoly and Yerdachellum, some forms of which 

 were described by Professor Forbes. 



Its principal characteristic is the abundance and variety of its Cepha- 



„, ^ . , , , lopoda, and in this respect it may be held to 



Chai-actcnsed by abun- ■'• ' i j 



dance of Cephalopoda. equal, if not surpass, the remarkable fauna of the 



Valudayur beds. The forms, however, are nearly all different, and for the 



Affinities of Cephalo- ^^«* V^""^ peculiar to this group. One or two 

 P°*^*- species of Ammonites, and possibly one of Ancy- 



loceras, (Hamites, Forbes,) occur both in the Valudayur beds and in 

 those of Ootatoor, but as a rule the Ammonites bear more resemblance 

 to upper Cretaceous species, and are in some cases identical with green- 

 sand and even white-chalk forms of Euroj)e. Some few of them also 

 pass through into the Trichinopoly Group, but the number of these does 

 not appear to exceed a very few species. 



The specific development of the genus Ammonite is not the only 

 instance of the richness of the Cephalopod fauna. Ancyloceras, Scaphites, 

 Turrilites, (Hamites ?) Ptychoceras and Baculites all furnish representa- 

 tives, but to what extent specifically, I am at present unable to deter- 

 mine. Nautilus also is represented by seven species and a great abun- 

 dance of individuals, while of Belemnites, (the only Dibranchiate genus,) 

 only three species have been distinguished. 



As a whole, the Cephalopoda recall the Gault fauna of Europe more 



^ , . 1 . .,. ^. than that of any other sub-division of the Creta- 



Gcological indications •' 



of Cephalopoda. ceous series, but this resemblance may depend in 



part upon the similar (argillaceous) mineral character of the two forma- 

 tions, or in other words, on the similarity of marine conditions. "We have. 



