242 



Memoir on the Geology of the 



joining the Bowany at Danikancottah, and under that name, after run- 

 ning about thirty miles, they discharge their water into the Cauvery. 



The Neelgherries*, being the highest hills in the whole of the penin- 

 sula, south of the Himalaya, possess a greater degree of geological in- 

 terest than any other group in this extensive region. 



Their being almost in the middle of a district, in which one of the 

 most interesting rocks in the Indian formations (the laterite) is found 

 developed in all its characteristic features, adds not a little to their im- 

 portance in a geological point of view. On account of their superior 

 elevation, they ought to be carefully examined by the geologist, before 

 he extends his researches to the other parts of the chain, of which they 

 form the most elevated point. 



It was, undoubtedly, after consideration of this kind, that the late 

 Doctor T urnbull Christie, of the Madras Medical Establishment, had 

 begun his geological survey of the peninsula from the Neelgherries, as 

 from a point where the rocks, found at a lower level, are seen in their 

 original state., unmodified, and unaltered by formations and deposits, 

 which events and revolutions, subsequent to the elevation of the whole 

 chain of the western ghauts, must have produced ; and had his life been 

 spared, he. would, undoubtedly, have given to the public the most accu- 

 rate and comprehensive account of the geological formations of this 

 interesting part of India, and would have settled many doubtful points 

 in Indian geology, which now keep many of the ablest geologists in a 

 state of uncertainty and suspense. 



The few memoirs he published regarding the geology, not only of 

 India, but of those places through which he journeyed, particularly of 

 Sicily, show what was to be expected from a man, who evinced so much 

 information and accuracy of observation on those subjects. Unfortu- 

 nately for Indian geology, he was cut off at the very beginning of his 

 labours on these very hills, which had in preference attracted his atten- 

 tion and researches. 



"We are told that the experienced eye of the geologist can easily 

 guess the nature of the rock composing a hill or a system of hills, by 

 the simple inspection of its outlines : thus, spiry peaks show the forma- 

 tion to he primitive; rounded smooth outlines are indicative of calca- 

 rious mountains; while the castellated ruin-like appearance of a moun- 

 tain, is proper to the sandstone formation. 



This criterion, however, would lead into error regarding the nature 



* " The Ncelgherry Hills ore situated between the parallels of ll 9 10* and 11° 32' N. 

 latitude, and 76° 59' and 77° 31' "fi. longitude from Greenwich ; their greatest extent in an 

 oblique direction, from S. W. to N. E. is from 38 to 40 miles, and their extreme breadth 

 15 ; taking in account the great undulations of the surface, and the breadth above stated 

 being pretty coastant throughout, their superficial extent may be fairly estimated at from 

 Q to 700 square geographical miles."— Baikie's Observatium on the Neetghcrries. 



