16 MEDLICOTT^ SHILLONG PLATEAU. 



the greatest change is observable. In the Khasia region the nnmmulitic 

 strata consisted of clear sandstones and limestones; here an earthy 

 element preponderates. The limestone is in thin layers, often lenticular, 

 nodular, earthy, and ochreous, and with shaly partings. There is a 

 thick bed of fine yellowish sandstone close above the limestone, but it 

 is overlaid by a considerable thickness of shaly clays, some pure and 

 plastic. I noticed no signs of a carbonaceous deposit. In the Cherra 

 district it would scarcely be possible to ascertain accurately the upper 

 limit of the nummulitic formation, the beds above the strong limestone 

 are so extensively denuded. On the Sumesari the investigation might 

 be undertaken, but the special object of my research in visiting this 

 region did not admit of my delaying for this purpose. There is a 

 strong band of sandstone overlying the clays, and of the saine tjrpe 

 as that associated with the limestone ; and in the section of the actual 

 river banks, there is a blank before the peculiar rock of the upper 

 tertiaries makes its appearance, so that, on the whole, there may be a 

 considerable thickness of true nummulitic strata ; at all events the 

 alteration observed in the calcareous and arenaceous deposits is in itself 

 remarkable. 



Forty miles further to the west, on the Kalu river, at the extremity 

 of the hiU region, the same change in the character of the nummuli- 

 tic deposits is stiU farther developed, and the contrast with the cretace- 

 ous rocks is very great. I could only observe the limestone in one spot : 

 at Domalgiri the massive clear cretaceous sandstone is well exposed in 

 the river, which flows from the north across the strike ; the southern face 

 of the sandstone ridge is strewn with blocks of earthy rusty concretionary 

 nummulitic hmestone, evidently derived from a bed on the spot ; and 

 there can be very little of it, for the stiff" overlying clays are in force 

 immediately above ; there seems to be little or no sandstone.^ 



* This limestone reminded me strongly of tlie nummulitic limestone of Sutathu in the 

 North-West Himalayas. 



( 166 ) 



