8 
[VOL. II. 
Records of the Geological Survey of India. 
3rd Group, Jummulmuddagoo Limestones, 
Wherever the above group of quartzites has been cut through, it is seen to be resting 
quite conformably on a thick series of shales and limestones; occasionally the shales thin 
out and nearly disappear altogether, and then the quartzites look to he resting directly on 
gray limestones. 
These constitute the second limestone group among the Kuenools, and they are 
generally easily distinguishable from those of the Khoond valley. The shales are generally 
of a buff color and are never calcareous, while the purple shales of the upper group are 
always more or less so ; and again the limestones are as a rule more crystalline and compact. 
There are, it is true, just as earthy and flaggy beds to be found in the upper as in the lower 
group, hut such beds are less frequent in the latter, and they are arranged in definite 
succession. There is generally a three-fold series, thus:—at the bottom, compact, sub¬ 
crystalline gray, and some purplish beds, with a thin series of peculiar limestone breccias ; 
in the middle, thick, compact-splintery dark-gray and hlueish beds; and thirdly, pale and 
dark-gray compact, sub-crystalline and sub-eartliy, often flaggy, bods. 
The more crystalline and compact beds weather in a peculiar coralloid manner; the 
worn surfaces being so radiately furrowed, pitted, and concentrically terraced, that the rock 
seems to he made up of two or three different forms of coral; but close examination has 
failed to show any organic structure. This coralloid appearance is characteristic of any 
great show of these lower limestones, though the same feature is also seen every now and 
then in the upper group. 
This generally more crystalline set. of limestones is seen at intervals, along the eastern 
side of the Khoond valley, in a narrow belt of outcrop at or near the western base of the 
Nullamullays. Again, on the western side of the same valley in Koilkoontla and 
Banaganpilly. and in the valley between the low Nosoom ridge and the Guudicott.ak 
hills, and so further south, in the western part of the Kuddapah basin, where the Herjee 
quarries* have been opened up in the thin and compact beds of the group). 
In the steep western slopes of the Gundicot.tah, Ramwarum, and Paneum ranges 
of hills, these limestones again come to light and form a narrow continuous terrace below the 
vertical scarps of upper quartzites, all the way from the topis of the hills east of Tadpurthee 
(Bellary district), up to within 24 miles south-south-east, from Kurnool, when it spreads 
out in wide sheets between the lower and gentler undulating hills which are here sinking- 
down to the flat country of Kurnool, itself built on a further out-stretch of these same 
beds. 
Here, in Kurnool, the group has thinned out a great deal, but still there are the three 
varieties of limestones in their propter order: the canal being cut in thin flaggy upper beds ; 
the more crystalline strata cropping out between the canal and the village of Calloor ; and 
the thin grey compact sub-crystallines, though altered much by local igneous action, showing 
close under the western bastions of the town. Thence, with the exception of some slight 
denudation in the Toongabudra and Kistnah, these limestones extend northwards to a 
few miles beyond the latter river, in the Hydrabad territory. 
In the Palndd there is the limestone again in great force. It here prresents identical 
characters with those in Kurnool and Kuddapah, excepit that it. is more extensively 
cleaved ; and that the white and buff uon-calcareons shales are only seen to a small extent. 
4th Group, Banaganpilly Quartzites. 
Lowest of all of these strata comes another quartzite group which is interesting as 
including the beds from which only diamonds are known to have been extracted in the 
districts under description. 
Hence, if the old nomenclature of “ diamond sandstone,” or “ diamond formation” was 
to he employed in a classification of Madras rocks, it would have to be applied to the Kuk- 
nools, or one of the groups included in that formation. There is no case known of diamonds 
having been found in quartzites of the Ivuudapahs, or in fact in any other group of 
■ These quarries were opened, and are now extensively worked by E. W. Barnett, Esq., who has used the stone 
whenever practicable on the Madras Railway, and l'or the new Madras University and other public buildings in the 
Presidency. 
