22 KING : NELLORE PORTION OE THE CARNATIC. 



badi there are frequent outcrops of granitoid gneiss much cut up by 

 numerous easterly and westerly small granular veins of white quartz 

 with pale yellow-green pistacite. Irregular strings of white quartz, 

 sometimes tolerably straight but oftener curved and branching, are com- 

 mon in this gneiss. 



The grey massive gneiss. — To the eastward of the boundary indicat- 



. n ed as strikingr a, short distance westward of Kala- 



Tlie grey gneiss or => 



Kaiabasti. hasti and Venkatagiri, hornblendic strings and 



nests begin to show in the red gneiss, and hornblendic foliated rocks 

 crop out of the wide-spread superficial coverings of this part of the coun- 

 try, after which the prevalent rock is a grey gneiss. This is in point of 

 fact all that can be said of the change from one variety to the other of 

 the massive gneisses, though there is no doubt that to the right or left 

 of this vague line, or rather extremely narrow interval, the rocks are 

 decidedly different in structure and constitution. The dip of the two 

 is eastward, their lie being very often vertical : so that in serial 

 order, the grey gneiss is apparently above or younger than the red 

 gneiss. 



The grey gneiss forms a band of from 10 to £0 miles in width, 

 alongside the red granitoid rocks as far north as Rapur, after which its 

 course is broken by the intervention of transition rocks, while there are 

 sudden alterations in the rocks of the band itself. The general north- 

 north-west run of the strike at the same time carries this band under 

 the strata of the Veligondas, and the outcrop north of the Penner is only 

 very narrow. 



While working at this division I was fain to consider it a syenitoid 

 A certain likeness to gneiss in contradistinction to the granitoid rock, 

 Southern India. from its being occasionally like the syenitoid rock 



of the Nilgiris and other mountain ranges of Southern India ; but it is 

 here more generally a foliated rock, and thus perhaps rather to be 

 ranged with the foliated gneiss of the low country of Coimbatore and 

 Salem. 



( 130 ) 



