2 MEDLICOTTj SHILLONG PLATEAU. 



as closely connected with these latter mountains j from which it is only 

 separated by a system of narrow continuous valleys. The lofty Burrail 

 ridge forms the south-eastern side of these valleys ; it runs steadily from 

 the north-east, cm'ves round most regularly to a westerly directioUj dying 

 out in the plains near Jynteapur. The detailed study of the drainage of 

 thjs region, as related to the structure, and as bearing upon the asserted 

 conversion of transverse into longitudinal'^ river courses, would probably 

 yield much instruction. The drainage of this series of longitudinal 

 valleys is very variously effected by several streams, all more or less 

 torrential. The Dunsiri, flowing north-eastwards into> Assam, drains 

 about one-half the total length ; and seems to have thus cut off, and 

 diverted along the line of easiest erosion, the original transverse system 

 of drainage from the Burrail across the table-land on the north-west. 

 On the south-west side the drainage is still transverse : the several 

 streams, of which the Jatinga is the most important, after the con- 

 fluence of their east and west tributaries in the longitudinal valleys, pass 

 southwards by narrow tortuous gorges through the Burrail ridge. This 

 course of the transverse drainage here, right across the ridge, forms a 

 very puzzling feature in the investigation I have suggested. 



The northern slopes of the longitudinal valleys along the base of the 

 Burrail form the face of the table-land, and are continuous with that 

 middle portion of it, which for the space of about fifty miles rises almost 

 immediately from the plains of Silhet. Still further westwards the bound- 

 ary of the table-land trends towards the west-north-west to Singmari on 

 the Bramahputra, leaving at the south-west angle of the Garo district a 

 width of twenty-five miles of low fringing hills : Thus the southern 

 boundary of the table-land proper forms a pretty regular arc of a circle. 



On the north the boundary of the high land is less well defined ; 

 there being broken ranges of low irregular hills stretching across Lower 

 Assam to the Himalaya ; they run into the table-land, being made of 



* It need hardly be stated that these terms have reference to the orographical system 

 of the region. 



( 15a ) • . 



