7 
206 KING: KADAPAH AND KARNUL FORMATIONS. [PART IIT. 
(v 
some ground for an unconformity between the two sub-groups, but 
further evidence of this was not obtainable. 
There are numerous thin bands of fine quartzite-sandstone, more 
flaggy beds, and very fine-grained thick-bedded 
Sands, flags, and cherts. 
calcareous sands and coarse cherts, associated with 
the slates at various levels in the series ; but these are more particularly 
in juxtaposition with the limestone beds. 
Ferruginous beds of quartzite are also common, the iron of 
which is sometimes very abundant, and is smelted 
Ferruginous quartzite. . See p : 
in some localities. Yerragoontla Cotta is an iron- 
smelting village; but here the iron (magnetie iron-ore) is mainly 
obtained from the quartzites to the west. There is a good deal of 
pseudo-laterite, or lateritic conglomerate and breccia, spread over the 
Yerragoontla and Codoor plains, which evidently derived their iron from 
© 
the ferruginous bands in this group, both slates and quartzites. 
In that part of the Yellaconda range to the east of Codoor there is 
th oe tect o © Socal Gaal On obscurity as to the lie of these 
east n: Poolumpett slates. They overlie the quartzites of 
the range south of this, or, rather, they once rolled over them into what is 
now the Nellore country. But they clearly must underlie the strata of 
Nagwaram hill-mass and those of Venkatigherry Droog. Mr. Charles 
Oldham’s sections indicate this; and he notes that the main mass of 
the western part of Nagwaram hill is of slates, with only a few bands 
of quartzites, and a thin series of the latter capping the higher parts 
of the mountain; so that the greater part of these strata must be 
of the superincumbent group. The Koyamon Conda, south of the 
Venkatigherry pass, is part of the rim of a dome; the rim, or Koyamon 
peak and its continuation into Cossy Conda, being of quartzites 
which underlie the Poolumpett slates. 
The eastern outcrop of these slates must then have cut across 
the Yellaconda ridges in the neighbourhood of Venkatigherry Droog. 
( 206 ) 
