302 Voysey’s Report on the Geology of Hyderabad. (Jung; 
The next division of the country consisting of basaltic trap is inter- 
esting from many causes: they are, viz. 
Ist. Its appearance on the upper half or summit only of some of 
the granite hills. 
2nd. Its transition from a highly crystalline compound of felspar 
and hornblende (the greenstone of Werner) to coarse and fine basalt, 
to wacken, and to iron clay, the passage being sometimes so gradual 
from one to the other, as to give the intermediate mineral an indeter- 
minate character. 
3rd. The direction and peculiar form of its ranges, the waving form 
of the land in some instances, and, in others, its flatness and conical 
peaks. 
4th. The intermixture of carbonate of lime with the wacken, the 
basalt, and even with some of the granite in the neighbourhood of the 
trap. 
5th. The black cotton soil, arising generally from the decomposi- 
tion of the basaltic trap, forming the banks of the rivers, and covering 
their neighbouring plains. It is also found at a considerable distance 
from that rock, and on heights so elevated as to preclude this cause in 
attempting to explain its origin. 
Ist. At Tandmanur, Suldapuram, Madcondah, Koulas, Baktapir, and 
Adampur, the granite forms the basis of the hill, and sometimes its 
lower half, and is covered by the trap, which in some instances has 
the appearance of having flowed partly down the hill when in a fluid 
state. In the immediate neighbourhood are hills, whose summits al- 
though much lower, shew no trace of the trap rock having once covered 
them. In one instance, the hill of Koulas, a vein of trap crosses one 
of these hills, but its appearance indicates rather an ejection from below 
than a deposit from above: it affords at the same time a good example 
of the identity of the greenstone, the basalt, and the wacken. 
2nd. The places the most remarkable for the changes which the 
basalt undergoes are Buktaptr, where it passes into wacken, Koulas, 
as above-mentioned, Beder, where the iron clay passes into both. The 
basalt is not always the lowest, as its greater specific gravity would lead 
one to presuppose, but is frequently above wacken. It is, however, 
always found beneath the iron clay. As a general description of the 
basalt, it may be observed, that it decomposes into round masses, hav- 
ing an exterior crust of a few lines in breadth, of a yellow or lighter co- 
lour than the interior. In the ravines, and where exposed to any depth, 
it resembles very much the drawings in vol. viii. page 171, Thompson’s 
Annals, of the Rowley Rag Basalt. Basaltic columns were observable 
