TRANS-HIMALAYA AND TIBET 41 



Colonel Burrard ^ in his map as the Kailas range, and he calls 

 it in this district " the northern rim of the Brahmaputra's 

 trough." 



Now it appears to be a not infrequent occurrence and a 

 very intelligible error for explorers to mistake a mountain wall 

 for a mountain range. For instance, to the south of Lake Van 

 and the Armenian plateau I found that the Taurus, instead of 

 being a continuous range running from north-west to south-east, 

 as it had hitherto been depicted on maps, was in reality a 

 mountain wall, in which the ends of closely serried S.W. — N.E. 

 ranges and mountain folds have been abruptly cut off by a 

 great N.W. — S.E. fault. The south coast of Lake Van rises up 

 precipitously into lofty snow-capped peaks and ridges, composed 

 of mica-schists, alternating with foliated grey and white marbles, 

 chlorite-schists, limestone-schists, clay-slates, etc., which are 

 certainly older than the Devonian. The continuous southern 

 boundary of the plain of Mush to the westward is identical in 

 structure and composition, forming a jagged and lofty wall, 

 running altogether for over a hundred miles in a N.W. — S.E. 

 direction, traversed by step-faults heading towards the plain and 

 the lake at its northern foot. An important characteristic of 

 this uptilted Tauric block of metamorphic schists lies in the 

 fact that the watershed lies quite close to the edge of its great 

 fault-scarp, and the main streams flow normal to its direction — 

 e.g. the Kulp, Ab-ul-Jevis, Batman, Bitlis, Ghindig, Mukus and 

 Mirjem rivers all flow from north-east to south-west — i.e. in 

 " consequent " courses along what must have been the original 

 slope of the uptilted block. 



1 have elsewhere^ shown at length that the eastern border- 

 ranges of Armenia similarly consist of uptilted blocks of ancient 

 resistant rocks, which had lost the plasticity necessary for being 

 thrown into folds. Here too the watershed of the Gokcha block 

 lies close to a lake (Lake Gokcha or Sevanga) and parallel to 

 its shore, and the rivers also take their courses in a direction 

 normal to the watershed and the strike-fault — viz. to the north- 

 east. Exactly similar characteristics are exhibited in the 

 Somketian block situated to the north of the Gokcha block, 



' A Sketch of the Geography a?id Geology of the Himalaya Moiuitains and 

 Tibet, p. 94. Calcutta, 1907-8. 



' " Zur tektonischen Entwicklungsgeschichte des armenischen Hochlandes," 

 Petermann's Ceop-aphische Mttteilunge?i, 1910, Januar-Heft, with structural map. 



