942 Notes, principally Geological, from [No. 130. 



of the strata subjacent : the observer must therefore dive into wells, 

 pass up the beds of rivulets that water the surface, search for quarries, 

 and descend into the fosses that surround fortified places. In failure of 

 all these, the walls of forts and other buildings present a mineralogical 

 collection on the large scale which usually affords a clue to the petro- 

 graphical nature of the surrounding formations, as natives seldom trouble 

 themselves to bring building-stones from any distance, preferring mud 

 if the former material be not at hand. The surface of the plain is 

 in general strewed with fragments of trap, amygdaloid, quartz, calcedony, 

 opal, cacholong, calc spar and zeolites, kanker, nodular iron ore, 

 and a conglomerate of ferruginous clay and iron ore imbedded in 

 compact kanker. These decomposing together in unequal proportions, 

 form a superstratum of a light brown soil, in which small crystals of 

 a pearly calc spar and zeolite glitter like particles of silvery mica 

 or talc, in soils formed by the decomposition of gneiss and granite. 

 This light-brown soil is extremely fertile, producing abundant crops 

 of wheat, chenna, bajra and juari : it is very different in colour 

 and appearance from the regur, which I have seen covering with 

 its black crust, rocks of all formations, at heights above the present 

 drainage level of the surrounding country, the granite and gneiss of 

 Bellary, a small part of Mysore, the limestone and sandstone of 

 Cuddapah, and the states at the foot of the Nulla Mulla hills. Beneath 

 this soil the trap, in public roads and other places liable to abrasion, 

 is often seen in the state of the concentric decomposition alluded to 

 in speaking of Beylhal, and also in a schistose form. In deep sections, 

 such as wells and quarries, the rock assumes a tabular appearance, 

 splitting almost horizontally into thick stratiform masses, which are 

 again intersected, at right angles, by almost vertical fissures, im- 

 parting a columnar structure. At Turvi, a village about four and a half 

 miles from the Mecca gate of Bijapore, beyond the ruined palace of 

 Aurungzebe, the basalt rests conformably upon a bed of amygdaloid 

 into which it passes. Large beds of the amygdaloid occur in the trap, 

 rising above its surface, as seen near the Allahpur gate of Bijapore. 

 The fissures, though nearly vertical, do not appear to indicate any 



, . axis of disturbance, dipping irregularly. At the 



rissures and joints. . 



bottom of a well at Tangoli, about fifteen miles 



south of Bijapore, the direction of the fissures was N. 25 W., dip W. 20 



