۰ 
14 KING: KADAPAH AND KARNÜL FORMATIONS. [PART I1. 
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It is moreover found where the formation is thick enough, that 
beneath the purple chert segregated beds—except 
Intercalated sand- 
He along what appear to have been the northern 
shores of this limestone sea,—there is a lower band 
of grey limestones with whieh are associated thin beds of sandstone and 
grit-quartzite which sometimes shade down by red and purple sandy 
shales to the next lower group of decided quartzites which are to be 
treated of 1n the following chapter. In the middle of the Koilkoontla 
limestone area on all the western bases of the- inner western hills, north- 
west of Banaganpilly, these intercalated or associated grits are not of 
much importance as regards their thickness or extent ; but to the south 
or south-west of the Oopalpád plateau, there is a very decided though 
thin series of two quartzites lying in the lower division of the limestone, 
and separated from the next succeeding lower group of quartzites by 
a band of limestone. At the same time this intercalated set of 
quartzites is of a lenticular shape, and thins out so much before the 
western scarp of KARNUL rocks is reached in this region that it is not 
seen in the scarp. This low vertical edge of the KarnUxs only shows 
a set of limestones with a seam of breccia overlying the lower group 
of quartzites. 
The rock of this intercalated band is peculiar in bemg a sandstone 
and grit-quartzite, and is m some beds partly 
Character of. 
made up of felspar in a crystalline state; except 
for the peculiar lustre of the felspathie element, the freshly broken rock 
is to the eye an uniformly coarse-grained sandstone or quartzite of a 
brown color. On weathered surfaces, the rock is pitted with shallow and 
narrow cavities, of an inch or less in length, in shape like the section of 
a flat convex lens: and these lenticular cavities are irregularly scattered 
over the surface of the rock, or, as is often the case, two cavities meet with 
their ends at an angle; or they occasionally cross each other and give a 
rude representation of a star. Freshly broken surfaces then show these 
lenticular bodies on a cross light, when a peculiar adamantine lustre is 
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