122 KHASI HILLS. 



These sandstones stretch inland from Cherra Poonjee to near Mow- 

 Sandstones extend into P^^l^°§ ("««« ^«iV> retaining on the whole their 

 nearly horizontal arrangement, and presenting 

 throughout the same general lithological character. This horizontality 

 of the beds, and alternating disposition of the shales, grits and coarser 

 sandstones, is well seen in the splendid cliff which bounds the great valley 

 of Cherra to the North. Here also dark earthy grits, with iron pyrites, 

 are seen to alternate with the sandstones. The same series again occurs 

 in the cliffs bounding the valley North of Lairungoo (see Fig. 1). The 

 total thickness of the group has, however, considerably diminished here, 

 and the metamorphic rocks come much nearer to the surface. But little 

 change in the mineral structure of the series is traceable. At one or two 

 places along the route, patches of coal (of very poor quality however) 

 occur associated with the sandstones (as at the Northern end of the Na- 

 tive village of Cherra Poonjee ; about half a mile further on ; and near 

 Surareem), and occasionally blackish-grey shales, with numerous small 

 fragmentary impressions of carbonized vegetables. At the roadside 

 near the Kala-pani, beds of dark earthy and pyritous sandstones and 

 shales, similar to those near to Cherra Poonjee, occur. 



Near to this, the sandstones begin to show the effects of the intrusion 

 „ , ^ , of volcanic rocks (to which we shall refer again). 



Greenstone near Jiala- '^ ' 



P^°i- both in th^r position, and in their texture. Drop- 



ping into the valley of the Kala-pani, about half way down the South- 

 Eastern side of the glen, we meet with highly crystalline greenstone un- 

 derlying the coarse sandstones. The beds in junction with the greenstone 

 have been greatly altered ; their colour has become a deep purple ; they 

 are intensely indurated, and are in fact quartz rock. Further, instead of 

 breaking into the laminar and irregular pieces, which these sandstones or- 

 dinarily yield, a blow of a hammer fractures the mass into small prismatic 

 blocks, having a semi-columnar structure. The original lines of deposi- 

 tion have, in fact, been obliterated, and a new series of divisional planes 



