KHASI HILLS. 151 



thei'e can be no doubt that there is a sufificient quantity to meet the 

 demands of many years to come. 



Igneous Rocks. — Geanitk — In describing the sedimentary rocks 

 Extent of area. in the preceding pages, I have in several places 



incidentally referred to the occurrence of granite, both in veins and 

 in mass. The largest area of this rock which occurs in that portion 

 of these hills we have visited, is near to the large iron-washing 

 villages of Molim and Nonkrim. Its boundary stretches with an irre- 

 gular outline from the Southern flanks of Shillong hill, passing the 

 villages of Lungqueer and Mawreng, and crossing the Boga-pani a 

 little North of Laikro. From this the boundary turns Eastwards, and 

 skirts the river on the Southern bank towards the village of Lailangkot. 

 Another large granitic area occurs to the West of this, stretching from 

 the village of Lybersai, South of the ridge on which are placed the 

 villages of Cockleederah and Cuddeiah, towards Lunkoi. 



Throughout this area, the lithological character of this rock is toler- 

 ably persistent. It is a highly felspathic and 

 largely crystalline rock : the felspar being of two 

 kinds, one whitish-pink, which together with the other ingredients forms 

 the general mass of the rock, the other of a deep flesh-red colour in 

 large crystals, which, imbedded in the general mass of rock, give it a 

 porphyritic character. The quartz is generally of a greyish-white tint, 

 but not abundant, the mica blackish and greenish-black. Hornblende 

 does occur, but is rare. The granite frequently presents also another 

 character, often seen in such rocks, namely, the occurrence of large 

 masses of a harder texture, and sliglilty different proportional composi- 

 tion, imbedded in the general mass. These masses are never so largely 

 crystalline as the ordinary granite adjoining. Owing to the large 

 amount of felspar which enters into the composition of the granite, it 

 decomposes readily, and for a depth of many feet from the surface is 

 quite soft and incoherent. 



