1856.] Report of the Magnetic Survey of India. 117 



chain of mountains, but a succession of several groups separated 

 very often by deep valeys. 



These groups do not even follow each other from East to West 

 on one and the same line ; but some of them, as, for instance, the 

 group of Nanda Devi and Trisoal, lie very much to the South, 

 while the next great group, that of Ibi Gamin, lies thirty or forty 

 miles more to the Northward. There are also iustances of several 

 central groups, or at least several nearly quite independent parts of 

 one system, lying behind each other, in making a section from South 

 to North, so that you have in going straight to cross a series of 

 snowy ranges. 



The best examples of the latter structure with which we are 

 acquainted at present, are the high groups of Bunderpunch and 

 Shergeroin near Jumnotri, with the high Dundar peaks North of 

 them, and the high mountains to the North and South of the Baspa 

 valley in Bisser. 



This arrangement of the central Himalayan groups reminded us 

 very much of the structure of the Alps. 



Altogether, indeed these central groups of the Himalayas have 

 much resemblance to the highest parts of the European Alps, both 

 in reference to the distribution and general form of the valleys filled 

 with numerous glaciers, as well as with regard to the forms of moun- 

 tain peaks and the character of vegetation. 



But these are nearly the only parts of the Himalayas which can 

 be compared with the Alps, the geological structure of all the rest 

 is extremely different. 



The prevailing rock of most of the Himalayan groups is gneiss, 

 passing into mica schist. It was only in some of them, as in the 

 Gangotri and Jumnotri groups, that we met with large and predo- 

 minant masses of true granite ; in some places this granite passed 

 into the remarkable rock protogine, or talc granite, which composes 

 the Mont Blanc group in the Alps. 



We felt considerable interest in investigating whether the " fan- 

 like" structure which prevails in many groups of the Alps, was also 

 to be found in the Himalayas.* As far as we have ascertained at 



* By M fanlike structure" is understood the curious phenomenon first discovered 

 in the Alps by Saussure, that in several instances the strata or planes of foliation 



