170 FOOTE : GEOLOGY OF THE BELLARY DISTRICT. 



isolated red felspar crystals were noticed scattered at wide intervals 

 in the black trap-mass. 



A fair number of dykes show porphyritic structure which is gene- 

 rally accompanied by a lovely greenish colour 



Porphyritic dykes. ... , - 



giving rise to a rock mass of great beauty 



admirably adapted for conversion into highly decorative porphyry. 



For beauty of colour and texture one of the most remarkable of these 



porphyritic dykes is that occurring three quarters 



of a mile to the east of Hurlihal (Hoorlyhall) in 



the south-eastern part of Kudligi taluq. The dyke, which is a very 



fine large one, is dioritic, and has a splendid rich green matrix full of 



pale green felspar (sanidine 9 ) crystals. Several large blocks which 



had been blasted when the new high road to Rai Drug was made 



showed its great beauty to perfection. 



Another very lovely green porphyritic trap is to be seen in a small 



dyke occurring at Kallakurti (Cullacoortee). 1 

 At Kallakurti. ' ° ,..,*.«. J 



mile south of Malyam (Maulyan) in Rai Drug 



taluq. The dyke is much obscured by the local cotton soil, and 



might be very easily overlooked, and the more so as much of it has 



been largely quarried by the villagers for building stone. 



In points of length the great majority of the dykes are under 



3 miles in length ; many indeed are traceable 



Length of the dykes. 



for less than a mile, but a few attain to greater 

 lengths ; thus two were noted above 5 miles ; five above 6 miles ; four 

 above 7 ; one each of 8, 9 and 14 miles respectively; three of over 

 19 ; one of 20 ; and lastly, one of 27 miles. Those exceeding 8 miles 

 are enumerated in the foot-note below in order of their length :— 



Miles. 



1. Joga, Avinamadugu dyke (Hospet taluq) . . . 27 J 



2. North dyke, Kamalapur (do. do. ) 



3. Adoni dyke (Adoni taluq) 



4. Kailasa Konda dyke (Raidroog taluq) 



5. Tambrahalli dyke (Haddagalli taluq) 



6. Kamalapur south dyke (Hospet taluq) 



7. North dyke, Wadderhalli ( do. do. ) 



8. Rajapur dyke (Hospet taluq) 



( 170 ) 



20 



I9i 



19 



19 



M 

 9* 

 8} 



