36 KING : NELLOUE PORTION OF THE CARNATIC. 



the northern development which has been denuded from the Vekatagiri 

 interval. The material of these reefs is Dearly always white quartz, much 

 cleaved and fissured, giving very sharp and acute-angled debris in long 

 fragments and splinters. There is often a good deal of schistose talc and 

 chlorite fragments distributed through the veins ; and small strings or 

 minute specks of micaceous iron ore are common. I only saw the faintest 

 traces of green carbonate of copper, or of copper pyrites, in the quartz 

 associated with the massive traps between Yarabali and Kaluvaya ; but, as 

 will be seen further on, it is rather in the traps themselves that the ores 

 of copper occur in this district. 



CHAPTER IV.— THE TRANSITION SERIES. 



Cuddapah Formation. 



This series occupies only a very small portion of the country, as com- 

 pared with the gneiss area, while it can be denned very simply as a set 

 of qnartzites and slaty beds belonging to three or more groups of the 

 Cuddapah formation. Full details of this Madras member of the tran- 

 sition rocks are given in the Memoir 1 devoted to its description, the 

 classification or grouping therein laid clown being as follows, in 



descending order : — 



f4. Kistna group. 



,. 1 3. Nullamallay group. 



CUDDAPAH FORMATION ... -I J 6 r 



) 2. Cheyair group. 

 ^1. Paupugnec group. 



The lowest of these groups is not, as far as is kuown, represented in 



The Cuddapah groups tne present area, but the strata of Kambak Droog, 



the Kalahasti ranges, and the Veligondas as far 



north as the parallel of Venkatagiri, are of the Cheyair group. A further 



reach of the Veligondas, as far as Rapur, is made up of succeeding beds 



of the Nullamallay quartzites and slates, and the rest of this range 



represents the Kistna group. The eastward outliers of this range and 



1 Mem. Geol. Surv. India, Vol. VIII, p. 1. 



( U4 ) 



