GEOLOGICAL NOTES ON ASSAM. 35 



tlie Tenia Gh^t I could only find a few blocks containing pebbles ; and 

 on the path over Wullong, three miles west of Terria, there seems to 

 be none at all. In the latter section the trap shows close under a very- 

 thick mass of ochreous earthy sandstone^ full of green chloritic matter ; 

 coarse ang-ular grains of felspar and of granite occur through it in 

 strings. All the bottom-group exposed on Tenia Ghat is of the same 

 description^ and several hundred feet in thickness. In both positions, 

 and probably more generally, it forms the scarp of the south face of the 

 range; the overlying strata being weathered back from it. I look 

 upon all this rock as the equivalent of the conglomerate and sand- 

 stone at the base of the sections at Cherra itself. The change in com- 

 position might, as I have suggested, be accounted for by the difference 

 in the underlying rocks. The thickness varies locally, l^ut there is a 

 steady tendency to a rapid increase southwards. 



The next stage in our conventional grouping includes the rough 

 sandstone forming the plateau of Cherrapoonjee 

 with all between it and the bottom beds. The 

 prominent rock is the yellowish sandstone, varjdng a good deal in tex- 

 ture, and containing more or less of earthy (felspathic) and calcareous 

 admixture, fine grey earthy beds, shaly or nodular, alternate with the 

 sandstone; they are very subordinate at Cherra, but are seen largely 

 developed above the scarp at Terria Ghat. These beds also vary in com- 

 position, being sometimes calcareous, sometimes green with chloritic matter. 

 The most remarkable case of rapid change that I noticed in this band was 

 on the two sections already mentioned at Cherra, though only about half 

 a mile apart ; on the most northern path there are several beds of slightly 

 sandy limestone, one very thick, just over the conglomeratic band ; while 

 on the southern path they are not to be seen, having probably merged 

 into sandstone. It is principally in this stage that the cretaceous fossils 

 have been found. The fossils are most abundant near the very base. 

 On Terria Ghat they occur in a yellow, crumbling, sandy rock of very 



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