GEOLOGICAL NOTES ON ASSAM. 45 



features undergo a complete change. The rocks assume a high and con- 

 stant dip towards the Burrail range. This is the actual continuation of the 

 unielinal flexure already noticed at the scarp south of Cherrapoonjee ; 

 and it would be natural to look here for the equivalent rocks of that 

 section ; but the evidence, both direct and indirect^ is against this assump. 

 tion. In this region the strata are much better exposed than where they 

 are horizontal ; in the deeply excavated longitudinal valley alono- the 

 base of the Burrail range, and in the steep water-courses on its flanks, the 

 rocks are well seen ; yet no intelligence of either coal or limestone has 

 been received, although both have been objects of enquiry to successive 

 Civil Ofiicers at Asaloo. The lime used at Asaloo is made from a tufa 

 found in the gorges of the Burrail, at a considerable distance to the 

 north-east, and possibly derived from some subordinate ingredient of the 

 rocks. Evidence of this kind is by no means to be despised, especially 

 in support of such flying observations as those I can bring forward. I 

 believe the rocks of the Burrail to be the same as those of Goomaigoojoo ; 

 and all to be supra-nummulitie. The best affinity I can suo-o-est for 

 them is Sub- Himalayan. The type is certainly less well defined than in 

 Upper Assam, but there is quite enough of it to make the supposition 

 plausible. Judging from these general considerations, and from some 

 features of the surface, I should be inclined to look for the coal-band 

 along the north base of the Longlye ridge, about twenty miles south of 

 the Kopili falls and five north of Waglai Village. The rusty fossiliferous 

 cretaceous sandstones are only found to the north of Longlye. This 

 ridge is the beginning of a considerable permanent rise in the general 

 elevation, on which the rocks are ot. this quasi Sub-Himalayan character. 

 Thus it would seem that over a large portion of the south-east corner of the 

 table-land area we have much newer rocks than elsewhere, and showing, 

 like others in this position, freedom from disturbance. There would be 

 nothing new in the appearance of the nummulitic band well in on the 

 table-land; and its complete concealment for a considerable space along 



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