6() On the Fossils of the Easteim Portion [Jul^s 



we meet with the same rocks to the north of the Godavery in connexion 

 with the fossil beds discovered in the great basaltic district. 



Granite Platform BETWEE>f the Kistnaii and Godayery. 



(See Map and Section I.) 



With regard to the granitic platform of the Deckan, which intervenes 

 between the Ivistnah and Godavery, much accurate information is already 

 before the public ; it will therefore be necessary only to observe, that 

 it is intersected by numerous greenstone dikes (sometimes of greenstone 

 porphyry), having for the greater part a direction from S. by E. to N. 

 by W., and not very different from that of several of the ranges of 

 basaltic mountains to the north. 



These dikes, and the detached masses connected with them, are 

 entirely composed of a crystalline compound of hornblende and felspar, 

 without distinct crystals of augite ; and I have never detected olivin e in 

 them.* The rock shows a tendency to separate into spheres composed 

 of concentric layers and into iiTegular prisms; and the same structure 

 in some degree occurs in the granite, sienite, pegmatite, &c. of the whole 

 of the south of India. The greenstone is exceedingly hard and dif- 

 ficult to work, but it takes a most beautiful and durable polish, as in 

 the magnificent mausoleums of Golcondah, the tombs of Hyder Ali and 

 Tippoo Sultan, at Seringapatam, and in many of the sculptures of the 

 Carnatic pagodasf. Where these dikes rise into hills, the summits only 

 are composed of the compact greenstone, which graduates below into 

 the granite of the surrounding country. Many of the veins of basalt in 

 the passes of the jMysore and Neilgherry mountains differ from these, 

 in possessing the structure of the compact basalt of Bombay and other 

 places in the trap countries, and in branching into narrow veins, (often 

 not an inch thick,) which traverse the granite without mixing with it ; 

 while the ordinary greenstone dikes of the Deckan are almost always 

 accompanied by separate nodules, of greater or less dimensions, insu- 

 lated in the granitic mass, the component parts of which appeared to me 

 to be there, in most cases, arranged in larger crystals, and to be more 

 subject to decay, than in other places. I could not resist the inference, 

 that, at the time of the formation of these dikes, the granite was in a 

 state approaching to fluidity ; although, as some of the narrow veins can 

 be traced for many miles through the granite, they do not appear to have 

 been formed at the same time. 



* *' In a specimen in the Geological Society's (-'ollection, taken by Dr. Voysoy from a 

 * greertJitme dike' passing through granite at Guntoor, south of the Kistnah river, olivine 

 s diffused amongst the other constituents of the rock." June 25th, l«.'j'J. 



t It is familiarly known in India as " black granite." 



