814 Memoir of Sylhet, Kachar, ^^ adjacent Districts, [No. 104. 



force itself on the attention, to which unquestionably the increase of 

 vegetation in this part is to be traced ; I allude to the numerous and 

 large granite boulders which are scattered in such abundance over the 

 country as to be occasionally mistaken for the crust or surface. The 

 granite has however never, as I before observed, been seen in any form 

 but that of boulders, nor is there any well established instance of 

 these having been seen otherwise than on, or partially imbedded 

 in the surface. I should remark, that the mass of granite, well 

 known as the Okillon. near Nungun and west of the Nungklao road, 

 may be considered of a dubious form, for though the dimensions are 

 enormous, the shape of the exposed part is that of a boulder. The dis- 

 integration of these boulders has of course largely contributed to 

 the formation of soil, especially when favoured by the configuration of 

 the ground, but wherever the boulders are missing, and the strata 

 preserve their horizontal position, vegetation remains likewise defi- 

 cient. 



As I am more anxious to record facts than to broach theories, I will 

 not indulge in speculations on the variation of the structure of these hills 

 from those around them, but content myself with observing, that there 

 is nothing in what I have pointed out at all inconsistent with the more 

 recent opinions as to the order, classification, and superposition of 

 the different rocks ; for though none of the unstratified rocks have been 

 seen in the positions which they might be expected to occupy in the 

 centre of the mountains, there is still no reason why they may not occu- 

 py a place under the sandstone, and have thus effected its up-lifting 

 without themselves protruding to the surface. Further inquiries may 

 throw light upon this subject, which is worthy of very great attention, 

 for if there be sufficient ground for the opinion here thrown out, the 

 geology of this country will furnish a strong proof of the igneous origin of 

 the unstratified rocks, and their more recent appearance above the surface. 



I have already remarked, that a bed of limestone extends along the 

 foot of the hills near Pundua, having its out-crop about five hundred 

 feet above the plains, where it abuts on the sandstone. The direction 

 of this bed is nearly east and west, and though frequently broken 

 through by rivers, it is continued westward (declining however in 

 elevation as it proceeds) to Bunsikura, where it is found in contact 

 with the plain, from which in other parts it is always separated by clay 



