1842.] of the Himmalay a Mountains, xlv 



nitude. At the confluence of the Buspa, the road lies along the foot 

 of this mass, and is strewed with fragments from it. 



87. Granite veins are evidently numerous in the neighbourhood of 

 Wongtoo bridge, for among the fragments that are met with for several 

 miles on each side, we observe a proportion of them to be granite. These 

 fragments often present undeniable evidence of their veinous origin in 

 retaining part of the gneiss which formed the wall of the vein, and 

 it was this circumstance, combined with the low proportion they bear to 

 the fragments of the gneiss, that first suggested the idea of their being 

 derived from that source. But there can be no doubt on this subject, 

 as in the immediate neighbourhood of the bridge, just before descending 

 to the river bed, these veins may be seen in great number intersecting 

 the gneiss, most commonly in a direction from N. E. to S. W., and again 

 in the anomalous rock at the bridge. 



88. The granite of these veins is always of a large grain, and is 

 remarkable for the very large proportion of felspar it contains, the 

 mica being comparatively deficient. The felspar is white and foliated, 

 the quartz of a light grey, the mica generally brown. No difference of 

 composition is observable between the middle and the sides of the veins, 

 nor any change in the gneiss in its neighbourhood. The breadth is 

 very various, and equally so the extent. The former is from a few inch- 

 es to several hundred feet. They occasionally divide, but they cannot 

 be said to ramify, at least not in a remarkable manner. 



89. The rock which occurs at the bridge, and which contains the 

 largest of these veins, is something of an anomalous nature, and might 

 be adduced as an instance of that transition between gneiss and granite, 

 which has been so often observed. Some specimens would certainly be 

 considered to belong to the former title, while others might be chosen, 

 which would as certainly be referred to the latter. It has, however, in 

 mineralogical aspect, a strong resemblance to the more well-defined gneiss 

 in its neighbourhood, while it has none whatever to the granite veins. I 

 may add, that its occasional want of a distinctly laminar structure, and 

 the indistinctness of its stratification, are the only obstacle to its being 

 considered identical with the surrounding accurately defined gneiss. 32 



32 It has been usual to call anomalous rocks of this description granitic gneiss, but 

 the mere giving it a name affords no new information, nor in any way settles the doubt 

 as to which type of rocks it should be geologically referred. 



