62 FOOTE : SOUTH MAHRATTA COUNTRY. 



in the ari*angement and aspect of the surface, I am inclined to regard 

 this Asmatti trap ridge as either a contemporary flow lying in the gene- 

 ral strike of the bedding of the gneissic rocks of this quarter ; or else 

 as a simply intrusive mass whose major axis is parallel with the general 

 lie of the bedding. Excepting its excessive width, this mass of trap 

 shows no peculiarity of mineral character of sufficient moment to render 

 it distinguishable on lithological grounds. 



As before mentioned, very few of the numerous trap dykes mapped 

 during the progress of the survey demand separate notice on account of 

 lithological peculiarities. The most noteworthy is a dyke of moderate 

 size close to the village of Arranalli (? Urranulli), about twelve miles 

 north-west of the great Madras Railway bridge over the Tungabhadra at 

 Kachapur. This dyke, although belonging, as regards direction, to the 

 " Doab ^' group, differs from the other members of the group in being of 

 a very pale diorite instead of the usual dark-blue or 

 greenish-black color; but a yet more noteworthy fea- 

 ture is that it forms a kind of breccia by inclosing numerous large and 

 small fragments of the blotchy hornblendic granite gneiss it has burst 

 up through. The included fragments are of all sizes and shapes; 

 many are laminar, others rudely spheroidal, and others again are thick 

 ano-ular lumps. Many fragments appear to have had their edges slightly 

 fused. The dyke is about two miles long, fully 60 feet wide, and runs 

 strictly parallel with the great Gutt Bichal dyke at a distance of about 

 two-thirds of a mile to the north. 



A small dioritic dyke, which occurs two and a 



Porpbyritic diorite. ■, ^(, • • • t • i 



haif miles north of Ling Sugur, is distmctly por- 



phyritic in character. The matrix is pale grey, and encloses numerous 



crystals of black hornblende about the size of a peppercorn. 



Another variation from the ordinary mineral character of the " Doab 



Compact fine-grained series " occurs in a dyke situated about six miles 



^"'^'^^y' north-north-east of Ling Sugur. In this dyke 



the rock is almost as fine in texture as pitchstone, and very different;, 



( 62 ) 



