24 MEDLICOTTj SHILLONG PLATEAU. 



with the main area. On the Laisoplia ridge there is the best section 

 of the sudden termination of the nummulitic group, and of the puzzling 

 association of the Cherra sandstone with the bottom conglomerate : 

 at the contraction of the narrow ridge from Surarim, at the south-west 

 angle of LaisopHa hill, the quartzose conglomerate of the Shillong 

 series, schistose and vertical, is weathered out for a few square yards, 

 capped by the cretaceous conglomerate ; the plane of junction is several 

 feet higher than even the nummulitic beds at 120 yards to the south j 

 on the south side of the saddle, which is about 70 yards long, the 

 cretaceous sandstones of the Cherra band form a Kttle scarp, and pass 

 continuously at a lower level round the west flank of Laisoplia hillj 

 at about fifty yards to the south of this first little scarp there is another 

 formed of the nummulitic beds, which are traceable continuously from 

 LairungaOj and are also distinguishable by the frequent carbonaceous part- 

 ings in them, while there are none in the Cherra band. The cretaceous 

 conglomerate seems to cover the surface of the metamorphics, tjbus 

 often occurring at a higher level than the beds I suppose to represent the 

 Cherra sandstone, The nature of the junction of the cretaceous conglo- 

 merate with that of the Shillong series is admirably exposed on the Jawai 

 road at this point of Laisoplia hill : there is no clean-swept surface of 

 contact ; it is difficult to say within a foot where one conglomerate ends 

 and the other begins, although the strata in the two are at right 

 angles to each other. 



Nothing could be more natural in making a cursory survey of this 

 locality in passing from Surarim to Maobelarka than to set down the 

 coal at the latter place as belonging to the nummulitic formation, in which 

 coal or carbonaceous debris is so constantly observable along the road 

 the whole way from Cherra to within a mile of Maobelarka. Even if 

 the stoppage of these beds on the south side of the barrier had been 

 detected, it might easily be supposed that the nummulitic deposits 

 came in again on the north side. By tracing the sandstone carefully 



( 174 ) 



