116 , ON THE GEOLOGY 



Gneiss facade, which forms the western exposure of the second. The 

 gneiss tract passing to quartz rock, the latter alone constitutes the 

 eastern quarter of the Condapilly cluster, while the final range of Beiz- 

 warra displays an extended deposit of argillaceous schist. The granitic 

 region exhibits in external configuration the ordinary classes of unstrati- 

 fied forms, but with diff*use variations in mineral character, presents no 

 determinate connections betwixt the elementary modifications, and those 

 of arrangement in mass. The rocky environs of Hydrabad, chiefly assum- 

 ing the concretionary structure in prisms, vertically superadded to the 

 bedded form, aftbrd in disintegration a wild assemblage of columnar 

 and cubic fragments : while irregular masses, wasting with spheroidal 

 contours, rise in the same vicinity in isolated mountain domes. The range 

 appears boldly compacted beyond the plain of the Moussy, one of the 

 numerous feeders of the Kistna, which here reticulate the land, and with 

 slight elementary alteration, a laminal tendency is there combined with 

 the bedded structure. The rock is of quartz and felspar, and usually 

 porphyritic by additional crystals of the latter, and the hue and lustre of 

 the quartz communicate a reddish shade, while neither the rounded nor 

 the prismatically fragmented characters continue eminent. In the course 

 of an easterly transverse valley, the bedded masses persisting upon a 

 cumbrous scale, the contours incline again to asperity and opake quartz, 

 with hornblende, slightly difiused, predominates in the rock. Beyond 

 Singaveram appear extensive masses of magnetic iron ore, now level 

 with the granite of the valley, now irregularly emerging over it, and 

 accompanied by beds of hornblende schist,* usual to this mineral in 

 primary sites. The approach to Malhapur is marked by a general 

 retirement of the hills, and an abraded rock overhangs the hamlet as a 

 large cupola upon the plain, alone affecting departure from the rugged 



* By this term varieties of Primitive Greenstone are conveniently comprehended. 



