the Eastern Portion of the Basaltic District of India. 567 



the south of the partof the basaltic district described by Colonel Sykes (Geol. 

 Trans., 2nd Series, Vol. IV.). The limits of this part of the formations have 

 been but imperfectly traced. According to Dr. Christie's observations and 

 my own, they are the same as those of the Cuddapah district*. The occur- 

 rence of sandstones and stratified limestones in this situation, is a fact of great 

 importance, which has escaped the notice of those, who have speculated on the 

 period of elevation of the great mountain chains of the peninsula. It was 

 for this reason, that I selected the line of section from Madras to Atchera, on 

 the western coast, within the limits assigned by Colonel Sykes to the basalt, 

 and near to which I discovered the sandstone below the escarpment of the 

 western ghats. (Section 2, Plate XLVI.) In the pagoda of the town, I ob- 

 served several quartzose sandstone pillars ; and I discovered the rock itself 

 forming a small range of hills to the south of the town, and dipping at a con- 

 siderable angle to the N.W. The stone is similar to that of the hills, near the 

 Chinoor diamond mines. The rock at the entrance of the inlet is laterite, 

 having the appearance of horizontal stratification ; and there are some indi- 

 cations of trap below it; but of this I could not obtain positive evidence. 

 Colonel Sykes, however, states that the basalt occurs a little to the south at 

 Malwan ; and 1 found it at Colter, and other places to the north, underlying 

 the laterite, at the foot and on the escarpments of the hills. These facts are 

 sufficient to show, that the elevation of the western ghats in this part of their 

 course, was posterior to the deposition of the sandstones, which, for the pre- 

 sent, must be considered as contemporaneous over all the districts described. 

 I am aware of the uncertain nature of mineralogical characters, as character- 

 izing different formations ; but in rocks exhibiting such remarkable appear- 

 ances and relations over such extensive areas, and when no organic remains 

 exist in them, I do not think it wrong, to place some confidence in the evi- 

 dence they afford, more particularly in the south of India, where the rapid 

 changes of formations, so common in Europe, are quite unknown. 



The speculations of Elie de Beaumont on the age of these mountains is 

 founded on negative evidence and analogies which appear to me to have little 

 weight; nor can I consider the remarks of Dr. Benza, founded on his excel- 

 lent researches on the geology of the Neilgherry mountains, as more conclu- 

 sive. The non-occurrence of stratified rocks and of organic remains in a 

 high granitic table land, affords no proof that these mountains have not been 

 recently elevated ; and the plentiful occurrence of ferruginous sandstone, 

 containing brown coal, lignite, and mineral copal, at the foot of the Travan- 



* Edinburgh New Philosophical Journal, 1828 and 1829. 



