62 KING : NELLORE PORTION OF THE CAItNATIO. 



but close on the trap the contorted beds are strong, with a west-by-south 

 to east-by-north strike. The western side of the ridge is a great mass 

 of east-by-south to west-by -north dykes traversing massive hornblendic 

 talcose and chloritic rocks and micaceous schists, having a north-west to 

 south-east strike, the traps being, however, greatly in the ascendant. The 

 dykes are generally of a massive coarse dark-brownish-green diorite, 

 which weathers into a coarse earthy ferruginous rock, while others again 

 are more of an aphanite. The highest part of the ridge is entirely 

 of massive and coarsely weathered trap, extending over many hundred 

 square yards. Along the south side of the ridge the character and 

 appearance of the rocks vaiy much. First, the trap forming the 

 summit is a massive well-crystallized rock of a dark-grey nearly 

 black colour of hornblende and felspar, through which run large, 

 probably segregated, strings of dense blue-black rock. Next, the 

 rock becomes more felspathic with the hornblende, showing in large 

 crystals, or oftener in small assemblages of radiating needles, giving the 

 weathered surface a starred appearance. This syenitoid character of the 

 rock extends up to the Vendodu tank. Vendodu itself is on coarsely 

 crystallized granitoid gneiss, perhaps rather a granite, a great band of 

 which passes along this side of the range past Vizinagram and Armenpadu. 

 Near these villages a band of coarse quartzo-felspathic rock, having a 

 somewhat laminated structure, and including angular fragments of 

 hornblendic schist, extends in a north-north-west to south-south-east 

 direction. The rock is very coarsely crystallized and is riddled with 

 numerous strings of quartz. To the eastward of this there is a band of 

 massive acicular hornblendic rock, and east of this again is more granitic 

 rock, after which come the schists with granitic strings and small trap 

 dykes above noticed as bordering the trappean ridge. There are no cases 

 of actual contact , the base of the hills being always covered with debris 

 of the rocks above, or else by the soils which run close up to the traps 

 of the hill masses. 



( HO ) 



