16 Geological Notes on the Khasi Hills. [No. 1, 



whole thickness amounting to about ten feet. The darker coloured beds 

 are seldom more than one foot thick, and the whole rests on a hard 

 thick bedded and light-coloured limestone (a?), the thickness of which 

 is unknown, although it must be considerable. 



In this section again, the unconformity of the upper sandstone 

 is apparent, masses of it are seen resting on all the above beds, in the 

 position of outliers, and are the remains of the upper series, deposited 

 against a high and irregularly scarped surface of the limestone 

 series. The dark umber coloured bed, with small Nummulites, 

 corresponds to the one mentioned, as seen on the north side 

 of the ridge, being the highest of the limestone resting on the sand, 

 but I am much inclined to think, that on that side (the north) 

 much of the limestone was denuded, prior to the deposition of the fos- 

 siliferous sandstones and shales. 



After leaving this section, one passes (on ascending to the crest 

 of the ridge to the west) on to coarse sandstone of the lower 

 group, infra- Nummulitic. There is no doubt of this, as on the 

 south-west face, after crossing the crest, these same rocks dip into the 

 valley at an angle of 10 degrees S. W. One again encounters the 

 nummulitic limestone near Purjonkha, clearing the strata, seen in a 

 ravine close to the field and belonging to the lower sandstones, on which 

 the limestone rests horizontally. From the sudden appearance of these 

 lower beds on the above ridge, close to the strata showing no sign of 

 bending or contortion, I am inclined to think that even between these 

 two last, a considerable unconformity exists, and that separation can be 

 established. The surface of the lower beds must have been locally 

 altered in level, before the nummulitic limestone commenced to be 

 formed. Throughout the great thickness of the lower sandstone with 

 coal, I have never found a single Mollusc or any remains, save those of 

 indistinct vegetable matter. According to the sections, noticed by 

 Messrs. Oldham and Medlicott, we should find, as at Cherra, the 

 cretaceous rocks here ; whether these sands with coal are their equiva- 

 lents, or whether they will be eventually found below, or above 

 them, and adjacent to the nummulitic formation, is an interesting 

 point, yet to be discovered ; — the probability is, that they are upper 

 cretaceous. 



From Nongkulang, direct to Maokerasi, a good section, displaying 



