the Eastern Portion of the Basaltic District of India. 575 



vered with alluvial soil, at right angles to the hills ; but it finds an exit through 

 them, by a fracture in the wall which in former times had apparently dammed 

 up its waters. The strata have been much disturbed, probably by the erup- 

 tion of the basalt, which is seen at the foot of the sandstone hills on the oppo- 

 site side of the valley, from which the Gundicottah range appears to have been 

 separated, PI. XLVl., Section 2nd. It should, however, be stated, that 

 ravines formed in this sandstone, by the action of the streams now flowing in 

 them, exhibit abrupt precipices, the opposite sides of which correspond to 

 each other as Voysey has described. 



The sections accompanying this paper were constructed by Capt. Smith, of 

 the Madras Engineers, F.R.S., from information contained in my notes made 

 during several journeys in the lines represented, and from some published 

 papers. The information is by no means complete, but, I believe, it will be 

 found to be correct as far as it goes. In consequence of the great length 

 of the lines to be represented, and the comparatively moderate height of the 

 hills, it would have been impossible to have given the different formations of 

 sufficient size to have been seen in a distinct manner without great distortion 

 of the strata, had the whole distance been represented. Breaks, therefore, 

 have been introduced, representing the continuance of the same rock for the 

 number of miles specified in each instance. In the Baulpilly valley and in 

 some other localities (Sect. 2.) the summits of the hills are almost inaccess- 

 ible, and it has consequently been impossible to represent them as they occur 

 in the exact line of section. I have therefore been content to exhibit the strata 

 as they occur at their bases, with the exception of a few of the hills which 

 have been more carefully examined, and which correspond in appearance to 

 those which are as yet unexplored. 



Section 1st passes from the Bangnapilly diamond mines to the valley of 

 the Nerbudda, with the view of connecting Section No. 1, across the penin- 

 sula, with a line running north and south through its centre ; and which 

 might easily be continued to the Himalayah mountains to the north and Cey- 

 lon to the south. 



Additional note referred to in page 545. — " In a specimen in the Geological Society's Collec- 

 tion, taken by Dr. Voysey from a * greenstone dike' passing through granite, at Guntoor, south 

 of the Kistnah river, olivine is diffused amongst the other constituents of the rock." June 25th, 

 1839. 



