1853.] and Seesee rivers in Upper Assam. 519 



tant points. The constant landslips that are occurring, would 

 make it difficult to say whether the masses of rock however large, 

 Which have been seen, were really in situ, or may not have been 

 detached from their parent site ages ago. We find also large tracts 

 of table-land lying along the edge of the North East mountains, 

 based principally upon well rounded granite and other primitive 

 rock boulders to which, from the apparent great age of the deposit, 

 a source cannot be assigued. However, the rocks in situ which 

 have been noted by Wilcox, in his journey from the I\ao Dihing to 

 Bot Khampti across the Great Duffa range, are conglomerate and 

 coarse sandstone near the Dihing, and gneiss passing into mica 

 slate, sienite and clay slate, on the high ridges. Inland from the 

 Brama Koond in the line of the Brahmapooter and its tributaries 

 in the Mishmee country also, granite, granite gneiss, sienitic gra- 

 nite, sienite, greenstone, serpentine, gneiss passing into mica slate, 

 primitive limestone and hornblend rock ; — primitive limestone of 

 a bluish grey and white, seems to be a very common rock. I 

 observed the rocks in the river below, and at the Brama Koond were 

 a stratified heavy schistose rock passing into chlorate slate, and ser- 

 pentine apparently. Between the Koond and the Degaroo river 

 and its sources, Wilcox marks the rocks as limestone, and the boul- 

 ders of this, which are annually brought down by the Degaroo, show 

 the existence of this stratum. A dirty white primitive limestone 

 associated with sandstone in large masses, is also visible near the 

 gorge of the Dihong river. Most of the landslips appear to be a 

 quartz or feltzpar rock of a reddish or greenish colour with veins of 

 decomposing feltzpar interspersed, the powder of which from some 

 of the scar appears to be kaolin. 



In the beds of the rivers in the tract of country defined, we find 

 the boulders composed of all the rocks before-mentioned, with many 

 varieties, and the addition of trap, porphyry, basalt and white quartz. 

 The last prevails in the bed of the Brahmapooter, the former in the 

 Dihong and Debong. In two of the small tributaries of the Dihong, 

 on the Assam side of the gorge, hard conglomerates and jasper 

 rocks are in situ. 



The mountainous region within the points here noted, and which 

 encircle the head of the Assam valley, cannot be considered as a 



3 u 



