GENERAL CONSIDERATIONS. I37 



I think few will doubt that every large mountain-chain is built up 

 of a body of Palaeozoic and crystalline rocks, merely flanked and some- 

 times partly covered by Secondary and Tertiary rocks ; whilst, on the 

 contrary, non-mountainous country is, as a rule, composed essentially 

 of the younger formations. Continuing the quotation above, we learn 

 that "old rocks certainly accompany and form part of all mountain- 

 " ranges ; but thay are only discoverable through the removal by denu- 

 "dation of the enormous masses of more modern sediment with which 

 "they were originally covered." He illustrates this by pointing to 

 India and saying " the Tertiary (system) alone, measuring 30,000 ft., 

 " has been upheaved and carved by denudation into the greatest moun- 

 tain system of the globe — the Himalaya." 



To the uninitiated reader the above remark would at once raise 

 the belief either that the only rocks found in the Himalaya were 

 of Tertiary and Recent date, or that older rocks, if found at all, 

 would only be discovered in the bottoms of ravines cut out by 

 river erosion, or along anticlinal axes : it would most certainly invoke 

 a vision of the Himalaya roughly blocked out of Tertiary strata. 

 Now, what is the real state of the case ? Over the greater part 

 known to us it is this : the Himalaya, rising to about 25,000 feet in 

 height, are composed chiefly of ancient gneissose granites, gneisses, 

 granulitic gneisses, and crystalline schists down to a level of about 

 10,000 feet. Below that, over a vast area called the Lower Himalaya, 

 there are chiefly quartzites, quartz-schists, traps and slates down to 

 the 3,000 feet level. There is then a narrow band of rocks averaging 

 only about 12 miles wide lying between the 3,000 feet level and the 

 plains, which is in reality composed of Tertiary rocks, namely, those 

 forming the subject of this memoir. If we could survey the Himalaya 

 from some great height above them, and a cataclysm were to take 

 place completely obliterating the Tertiary rocks, we should be quite 

 unconscious of it. It would in fact be a mere flea-bite to the Hima- 

 laya as a whole. 



Ridged one behind and above the other, the Tertiaries may be said 

 to rise from the plains in height and distance according to their 



( 195 ) 



