2 Geological Notes on the KJiasi Hills. [No. 1, 



First and lowest ; the coarse sands and conglomerates, resting on 

 the trap and metamorphic rocks. 



Second ; the rough tabular sandstone of the Cherra plateau, with 

 all the beds between it and No. 1 ; — Cretaceous. 



Third ; the limestone, sand and shale with coal, that rise on the 

 west of Cherra, forming what is locally known as the coal-mine hills ; — 

 Nummulitic. 



Of the oldest rocks the trap, as one proceeds northwards, is the most 

 conspicuous, and as shown in Mr. Oldham's geology of the Khasi 

 Hills is in great force in the bed of the Kalapani, and Bog Pani rivers. 

 It is seen for the last time beyond Mofflang on the road to Mairang, 

 and in the bed of the stream from Mofflang near Langiong, on the road 

 to Nongspoong. A rough section as observed on a march from the Boga 

 Pani, in this latter direction, appears as given in section a, pi. I. The 

 unaltered position of the sedimentary sandstones, and grits resting on 

 the trap, and the great difference of level and exposed surface of the 

 last, with the high dip of associated metamorphic shales and older 

 sandstones, show a very decided unconformity and lapse of time 

 between the two formations, as well as the prior contortion of the 

 metamorphic shales on the first upheaval or depression with the trap. 



The sudden and final termination of the nearly horizontal strati- 

 fied rocks, is nowhere better seen, than on the road between Lookla 

 and Langiong ; this would strike the most unobservant traveller, more 

 particularly if he were coming from the northward. From the great 

 northern scarp to the Lookla valley all is metamorphic rock, gneiss or 

 granitic formation ; giving the usual peculiar features to the country of 

 humrocky rounded hills, steep falls encumbered with enormous 

 weather-worn masses of granitoid rocks, and many a grassy hill 

 capped with a dark grey, single or double boss of the same. To the 

 geologist the only sections exposed shew an interminable succession 

 of coloured soft-bedded gneiss, always dipping at a very high angle, and 

 of a regular strike which has given a like parallelism to the natural 

 features of the country, its ridges and drainage lines. 



On marching from north to south, and arriving at the village of 

 Pumsungut situated on the ridge, that bounds the valley of the Um 

 Lookla, the change is most sudden ; one walks off the dark grey 

 granite on to a perfect shingle beach, and topping the ridge at the 



