INTRUSIVE ROCKS IN THE ARCH/EAN AREA. 1 77 



of the specially epidotic tracts of the peninsula, — a tract which 

 extends into the adjoining Karnul district to the westward of Mad- 

 dikerra railway station and the Guntakal junction. This great vein, 

 which is to a great extent obscured by the overlying regur, must 

 measure many yards across. 



A good-sized vein several feet in diameter is exposed for a few 

 yards distance in a rain gully to the eastward of the white quartz-run 

 north of Ram Drug hill. It shows a sharp clean-cut line of contact 

 with the country rock (which is a hornblendic granite), in which 

 neither side shows any alteration. 



Away some 20 miles to the north-west of this great epidote 

 granite vein on the high ground between Hira Harrivana (Heery 

 Hurravana) and Gejjahalli are at least two considerable groups of 

 good-sized epidote granite veins traversing the felspatho-hornblendic 

 granite there forming the country rock. The rock, though not in suffi- 

 ciently large masses to be of appreciable value for decorative 

 purposes, is one of great beauty, the rich green of the pistacite 

 (epidote) contrasting admirably with the warm pink or red of the 

 felspathic constituent. 



E. Enstatite rocks, veins and necks. 

 Dykes and necks of enstatite rock are uncommon throughout the 

 south of India, and only a few instances of its occurrence have been 

 noted, of which three lie within the limits of Bellary District. They 

 are of special interest on account of their rarity. 



The most striking of these three examples is the one occurring a 

 Near Alur. m ii e to the south-west by west of Alur taluq 



town. It is a big mass of intensely black rock rising out of the 

 cotton soil, and is about \ mile along its major axis, and approxi- 

 mates to an ellipse in plan. 



Mr. Lake regarded this rock as a hornblendic picrite. 

 A small band or dyke-like intrusion of enstatite rocks occurs 

 Dyke on Malleshwa- rather more than 6 miles to the north-west by 

 ram gu a. wegt Q £ ^ ^j ur nec ^ on t k e wes t e rn side of the 



fine hill known as Malleshwaramgudda. Its relation to the general 



M ( 177 ) 



