94 



On (he Fossils of the Eastern Portion 



[July 



argillaceous limestone to be interrupted by a narrow band of granite, ex- 

 tending from the delta of the Kistnati to the granitic platform of the 

 Deckan. Some of the hills, however, have caps of sandstone. In the 

 present state of our knowledge, it is difficult to form any correct notion 

 as to the dip and direction of these rocks. Indications of derangement 

 and elevation by the granite are, however, sufficiently apparent. 



Sandstones and schists of the same characters, and associated with 

 the same rocks, are also extensively distributed along the great tribu- 

 taries of the Kistnah, in the southern Mahratta country, near the west- 

 ern ghats, and a little to the south of the part of the basaltic district 

 described by Colonel Sykes (Geol. Trans., 2d Series, vol. IV.). The 

 limits of this part of the formations have been but imperfectly traced. 

 According to Dr. Chrirstie's observations and my own, they are the sam.e 

 as those of the Cuddapah district*. The occurrence 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, oa 

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

 basalt, and near to which I discovered the sandstone below the escarp- 

 ment of the western ghats. (Plate, Section 2). In the pagoda 

 of the town, I observed several quartzose sandstone pillars ; and I dis- 

 covered the rock itself forming a small range of hills to the south of the 

 town, and dipping at a considerable 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 horizon- 

 tal stratification ; and there are some indications 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 nouth at Malwan ; and I 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 present, 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 ap- 

 pearances 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 evidence they afford, more particularly in the south of India, 



• Edinburgti New Philosophical Journal, 1828 and 1829. 



