770 0?i the Physical Geography of the Himdlaya. [Aug. 



what miners call "a fault" in the ghat line of the snows, which line, 

 after proceeding N. Easterly from the Lachen to Powhanry,* dips sud- 

 denly to the south for nearly 40 miles, and then returns to Chumalari. 

 A triangular space called Chiimbi is thus detached from the Himalaya 

 and attached to Tibet ; and the basin of the Thista is thus narrowed 

 on the east by this salient angle of the snows, which cuts off the 

 Chumbi district from the Tishtan basin, instead of allowing that basin 

 to stretch easterly to the base of Chumalari. Chumbi is drained by the 

 Machu of Campbell, which is doubtfully referred to the Torsha of the 

 plains, but which may possibly be identical with the Hachu of Turner 

 and Griffiths, f or the Gaddada of the plains. But besides that these 

 points are still unsettled, it will be noted that one of the transnivean 

 feeders of the Tishta rounds Powhanry and rises from a lake (Cholamu) 

 approximating to Chumalari ; so, that, one way or another, the Tishta 

 may be said, without much violence, to spread its basin from Kang- 

 chang to Chumalari. 



Chumbi and all the adjacent parts of the plateau of Tibet, constitute 

 a region as singular as is the access to it from Sikim by the Lachen 

 pass. That pass surmounted, you at once find yourself, without de- 

 scent, upon an open undulated swardy tract, through which the eastern 

 transnivean feeders of the Tishta and of the Arun sluggishly and tor- 

 tuously creep, as though loath to pass the Himalaya, towards which 



* Vide Waugh's outline of the snowy range of Sikim, J. A. S. loc. cit. 



t Embassy to Tibet and J. A. S. Nos. 87 and 88, with sketch maps annexed. Also 

 Pemberton's large map of the eastern frontier. Rennell is not easily reconcile- 

 able with them. In the accompanying map I had identified the lakes of Cholamu, 

 which give rise to the Tishta, with Turner's lakes. But I now learn from Hooker 

 that the latter lie a good deal east of the former, and I am satisfied that Campbell's 

 Machu is distinct from Turner's Hachu. We need, and shall thus find, space in 

 the hills correspondent to that in the plains watered by Rennell's Torsha and Sara- 

 dingoh and Gaddada and Suncosi. The Machu, (Maha tchieu apud Turner) rises 

 from the West flank of Chumalari. The Hachu of Turner is a feeder joining his 

 Machu from the West. The Chaan chu of Turner is the Sunc6si of Rangpur : his 

 Tehin chu is the Gaddada, and his Maha chu, the Torsha. The Arun has its 

 rise in the broken country of Tibet lying N. and a little W. of the sources of the 

 Tishta and South of the Kambala, or great range forming the Southern boundary 

 of the valley of the Yaru. This broken country Dr. Hooker estimates at from 16 

 to 18000 feet above the sea. It is a good deal terraced near Himachal. 



