1857.] Report on the "Progress of the Magnetic Survey. 117 



The mean direction of the principal crest of the Knenluen which 

 forms the water-shed between Ladak and Tnrkistan, runs north- 

 west to south-east from the sources of the Tarkand river to Kudok. 

 Another more northern chain independent of this, and of a com- 

 paratively smaller elevation, runs from west to east ; this is the 

 chain over which Passes lead from Bushia and Elchi to Yurunkash, 

 Keria, &c. The fall of the upper portion of the rivers Tarkand 

 Deriao and Karakash Deriao is not great. Bat the rivers descend- 

 ing from the other ridge, which runs from west to east, have a much 

 more rapid descent, particularly the rivers on the northern side of 

 this ridge. 



We succeeded in procuring, besides our own routes, itineraries of 

 the commercial routes to Badakshan, Tarkand, Kashgar, Kokand and 

 to Aksu, from the different caravans we met with. The information 

 thus obtained from independent sources was very consistent as re- 

 garded the number and succession of the halting-places and their 

 distances from each other. It is scarcely necessary to add that we 

 found Baron Humboldt's " Map of the Mountain Systems and 

 the Volcanoes of Central Asia" of the greatest assistance in making 

 our own observations and in prosecuting enquiries for routes. 



Geology. 



To the north of the Nubra Yalley much lime (chiefly carbonate, 

 combined with large masses of sulphate of lime) is met with ; but 

 alternating in such a manner with crystalline rocks, that it can 

 scarcely be thought to be sedimentary ; it also appears nowhere to 

 contain fossil remains. On the northern margin of the Kuenluen, 

 crystalline rocks appear to extend to the foot of the mountains, and 

 if a margin of sedimentary rocks exists, it can only be very narrow. 



We very often met with a hard crystalline rock, not unlike 

 pudding stone, which contained enclosures of spherical and angular 

 forms. We also came to quarries, where the Tashem stone is dug ; 

 they are at Gnlbagashen in the valley of Karakash. We took a 

 good quantity of the best specimens with us for future analysis. 



Two systems of cleavage predominate, which are particularly re- 

 gular in the central parts of the Kuenluen : the steeper one dips 

 North 30° to 50° East, the other South 20 to 40° West. 



