96 



CRETACEOUS ROCKS OF S. INDIA. 



[Part II. § 1. 



direction, except to the North of the principal nullah (see Map), where two beds of con- 

 glomeratic grit appear to have a gentle and pretty regular dip to the West. Even here 

 I could not ascertain the amount of the dip, and I think it probable that such dip as exists 

 is duo rather to original deposition on a sloping bottom or sub-marine bank than to any 

 subsequent disturbance. The matrix in which the boulders are 

 imbedded is usually a fine sand or sandy shale, composed of the 

 abraded gneiss, but at the spot where the sketch (Fig. 11) is taken, it consists of a fine 



Boulder bed. 



Fig. 11. BOULDEK-BED NEAR MaLARASURE. 



ochreous clay, resembling that which forms many beds of the Ootatoor Group. The boulders 

 are of all sizes, from 5 or 6 feet in diameter downwards. Of those shown in the accom- 

 panying sketch, a nullah bank near Malarasure, the large boulder in the foreground measured 

 5 feet in length by 4 in breadth, its height coidd not be estimated, as it was half 

 buried in the sand of the nullah ; those lying arovmd were also many of them 3 or 4 feet in 

 diameter. 



Sometimes intercalated with the boulder-bed irregular masses of fine micaceous shale occur, 

 Micaceous shale. having, except in the absence of regular bedding, much resem- 



blance to the plant shales in the neighourhood of Ootatoor ; but I 

 have never found any ti-ace of imbedded plants. 



The principal interest of this locality is due to the occurrence of molluscous fossils, which 

 Po5gilg_ are abundant in some of the coarse grit bands. The species are 



indeed few in number, and so far as my memory and a hasty exa- 

 mination in the field enabled me to judge, aU, except perhaps a belemnite, pecidiar to these beds ; 

 but in this I am open to the coiTection of subsequent comparison. The most common species is 

 a large thick-shelled oyster, which in some spots is so abundant as to form about a quarter of 

 the entire mass of the deposit, and which occtu-s both entire and in separate valves, more or 

 less rolled. Next to this in importance is a large thick-shelled Trigonia, with broad nodulose 

 ribs, which is abundant only in one bed, but which I have also met with at another locality 

 South of CuUygoody, presently to be described. Of the other species I have only seen 



