M. Voysey on the Diamond Mines of Southern India, 103 



Baen Ganga, and in the plain of Nandiala, arising from the de- 

 composition of the basaltic trap rocks, in which all these 

 rivers or their tributary streams take their rise. Beneath this 

 upper stratum, it is mixed with masses and rounded pebbles of 

 sandstone, quartz rock, jasper, flinty-slate, granite, and large 

 amorphous masses of a calcareous conglomerate, bearing no 

 mark of attrition from the action of running water. In this 

 stratum the diamond and other precious stones are found. The 

 excavations are of various size, but from fifteen to twenty 

 feet deep. 



The labourers are a little more under control than at Ban- 

 ganpali ; and they pay a trifling duty to the Nizam's agent 

 stationed in the village. The mode of search is precisely the 

 same as that above described. 



The mines of Ovatampalli, and of Canparti on the right 

 and left banks of the Pennar, near Cuddapet, are in an alluvial 

 soil of nearly the same nature ; it is not quite so black, from 

 the greater admixture of debris of sandstone and clay-slate. 



In marty parts of the plain of Nandiala, diamonds were 

 formerly sought for, but the mines have for a long time ceased 

 to be productive. 



The failure of the mines of the Dekhin may perhaps be 

 principally attributed to the cheapness and plenty of Brazil 

 diamonds ; otherwise, from the vast extent of the rock in which 

 they are found in India, there are scarcely any limits to the 

 search for them. It may be assumed then, 



1st, That the matrix of the diamonds produced in southern 

 India is the sandstone breccia of the clay-slate formation. 



2d 9 That those found in alluvial soil are produced from 

 the debris of the above rock, and have been brought thither by 

 some torrent or deluge, which could alone have transported 

 such large masses and pebbles from the parent rock, and that 

 no modern or traditional inundation has reached to such an 

 extent. 



3d, That the diamonds found at present in the beds of the 

 rivers, are washed down by the annual rains. 



It will be an interesting point to ascertain if the diamonds of 

 Hindostan can be traced to a similar rock. It may also be in 

 the power of others more favourably situated than the writer, 



