1836.] 



Southern India. 



335 



same character, until reaching- the latitude of the Naggery hills, where 

 green felspar strata again occur. The connection of these with the 

 ghauts might be determined by taking their direction ; as long as the 

 direction of the strata continues E. and W. while that of the ghauts 

 is N. and S. a progressive change or succession of strata may be look- 

 ed for : and different rocks, which originally had nothing to connect 

 them into a mountain chain, receive, by cross fracture, the new cha- 

 racter of elevation in a common line. 



Superior elevation has been considered an usual character of the pri- 

 mitive rocks ; regular crystallization has also sometimes been insisted 

 on, as a mark of early formation: the following observations on this 

 head apply to the south of India. Rocks of confused crystallization, 

 as trap and sienitic granite, have the highest elevation, and at the same 

 time the greatest depth, while the more perfectly crystallized granite 

 is found at moderate heights or on the plain : as this elevation is, in 

 every instance, a protrusion of fragments, or rising of a part above the 

 general level, it follows that where the greatest dislocations occur the 

 understructure will then be revealed to the greatest depths ; this, along 

 the escarpment of the western ghauts, amounts perhaps to four thou- 

 sand feet, the rock seen being still the trap and sienitic granite, dispos- 

 ed as usual in vertical strata. Where the original surface has not 

 been raised, even the primitive rocks remain at a very low level : while 

 the convex hills on the Neelgherries have attained an elevation of 

 seven thousand feet, hills, of precisely the same description, remain in 

 the plain of Coimbatore at an elevation of little more than four hun- 

 dred feet ; and, following the course of the same rocks towards Madras, 

 we find them, at the level of the sea, covered by tertiary formations, and 

 by a sea-beach of the present period. 



Of the Himalayan chain we are told that the principal valleys are 

 perpendicular to its direction, running N. E. and that the escarpments 

 are generally on the N. W. side, while the S. E. is shelving; but we are 

 entirely ignorant regarding the direction of strata, whether the 

 chain in its progress crosses many different kinds of rock in succession, 

 or whether there are continuous rocks of any one kind extending from 

 Bootan to Cashmere. Gneiss is said to be the most predominant of the 

 primitive rocks and strange to say " gneiss reigns paramount in the 

 Andes" : the fact seems to be that all granite, when fully exposed to 

 view in large masses, is more or less stratified; and hence is as liable to 

 be called gneiss as granite. Much of this gneiss may on comparison 

 prove the same as our primitive trap, which appears to be a very widely 

 extended rock, for green granite is mentioned as entering into the com- 

 position of the Hindoo Koosh. 



