10 eoote: GEOLOGICAL STRUCTURE OF THE eastern coast. 



everywhere coincident with the strike of the bedding, and appear to be 



axes of areas of extra metamorphism. The larger of the two principal 



o-ranite gneiss bands occupies the centre of the gneissic area, and 



_ ., . , extends from a little south of the Paleru in Nellore 



The four granitoid 

 areas, central and western, district up to and beyond the Kistna. The 



smaller or western band extends from the Kistna south-westward to 



the Gundlakamma river close to Vinukonda, its western margin being 



overlaid by the Kadapa rocks ; but it is exposed in various inliers which 



will be separately referred to further on. 



Two other areas of granitoid gneiss of lesser but still considerable 

 size occur, the one in the extreme south-west corner of the gneiss region 

 described in these pages, the other pretty nearly in the centre of this 

 region. The former may be conveniently called 

 ram & anT Chimakurti the Chandra Sekharapuram 1 area, after the large 

 areas * village situated near its centre, and the latter the 



Chimakurti area, after the Chimakurti mountain which forms it. Be- 

 sides these larger granitoid areas there are several quite small ones 

 scattered here and there through the schistose areas, but they are not 

 very well defined and of no special importance ; only a few of these will 

 have to be mentioned separately. 



The schistose rock-area is divided, except at its southern end, into 



The schistose area and tw0 g reat bands > h J the main band 0r area of tne 

 Dands « granitoid gneiss. The eastern of these bands^ 



which extends northward from 15° 15' to 16° north latitude, consists 

 mainly of hornblendic varieties of gneiss; the western, on the con- 

 trary, consists mainly of micaceous beds and associated quartzites, 

 but includes some hornblendic beds in its southern part beyond the 

 Gundlakamma river. The eastern schistose band contains also a few 

 quartzite beds, and in several detached groups a number of beds of mag- 

 netic iron, some of which are of considerable richness and possibly of 

 future importance economically. 



1 Chendra Shakrapoorum of sheet 76. 



( io ) 



