40 CRETACEOUS ROCKS OF 8. INDIA. [PaRT II. § 1. 



at the extremity of this dyke, where two small branches of the nullah 

 meet, that the plant-beds crop out ; and in the broken ground drained 

 by the upper branches of the nullah, the coarse sandstones, with inter- 

 calated bands of soft white and grey shale, of which they consist, are 

 exceedingly well exposed. 



The bottom bed is a coarse, ferruginous sand, containing pebbles and 



large blocks of gneiss; the latter always much 



Coarse conglomerate, i. i j.i o r a 



decomposed ; one of these was not less than b leet 



long by 5 broad, and probably as much in height. Its height could only 

 be guessed at, as it was half embedded in the matrix. It was rounded and 

 quite decomposed, and it is probable that this decomposition of the mine- 

 rals may have been complete previous to its being embedded in the sandy 

 matrix. It is a noteworthy fact, that at this locahty, and indeed generally 



where the plant-beds rest on the gneiss, the latter 



Gneiss decomposed. , . ^ -, • i ^ ^ t i^ i 



rock IS decomposed to a considerable distance, and 



frequently to such an extent, that where the foliation is well marked, the 



decomposed gneiss has been mistaken both by myself and some of my 



colleagues for a bedded micaceous sandstone. Elsewhere, in the country 



immediately around, this decomposition of the gneiss is not usual, and it 



is also rarely seen where beds of the other groups rest upon that rock. 



The conglomerates are succeeded by a series of fine micaceous 



shales, alternating with sandy shales and coarse 



Succeeding beds. , , , ,■, . , . , 



semi-consolidated sands similar to that which 



forms the matrix of the boulder-bed.* These beds are exposed in 



* The term " boulder-bed" used here, as -^ell as on the map, is convenient as tending to 

 distingtiish these from ordinary and more widely spread conglomerates. But it must not 

 be taken as implying that the blocks imbedded have been carried to any distance from their 

 orio-inal locality. These coarse " boulder-beds" appear to be precisely what would result 

 from the deposit of a tolerably fine sand, or silt, around and among the numerous and fre- 

 quently very large blocks, which now strew the ground at the base of any of the isolated gneiss 

 hills of the adjoining district. In all respects these rocks appear of a similar origin, and are, 

 in fact, nothing but the deposits locally formed in this manner close to the old shores around 

 which these plant-beds were originally accumulated. They arc generally extremely local. 



T. Olduam. 



