356 



Geology of the Deccan. 



[Oct. 



Ferruginous Clay. — The next distinctive feature is the occurrence of 

 strata of red ochreous rock, in fact, MacCulloeh's ferruginous clay un- 

 derlying thick strata of basalt or amygdaloid, precisely as is seen to be 

 the case in the Giant's Causeway in Ireland. It passes through evesy 

 variety of texture, from pulverulent, friable, and indurated, to compact 

 earthy jasper. The stratum is from an inch in thickness to many feet. 

 The rock makes a red streak on paper, with the exception of the very 

 indurated kinds, and does not affect the needle. It is pulverulent near 

 the basaltic columns at Serroor, friable under sub-columnar red amyg- 

 daloid, near the source of the Seena river, indurated under basalt at 

 Kothool. Although hard, it is here so cellular as to have the appear- 

 ance of sponge, and reduced to powder, looks like brickdust. 



In the scarps of the hill fort of Hurreechundurghur and a mountain 

 near Joonur in which are excavated numerous Boodh cave temples, it 

 is found compact and homogeneous, and is, in fact, an earthy jasper. 

 In these localities it lies under from three-hundred to six-hundred feet 

 of basalt. In the former locality it is about three feet thick, in the lat- 

 ter one foot. At Nandoor, north-north-west of Ahmednuggur, in the 

 valley of the Godavery river, it is found as a porphyritic stratum, many 

 feet in thickness, and is used as a building stone. The imbedded mat- 

 ter consists of very minute crytsals of lime. At Wangee, lying nearly 

 in the latitude of Barlonee, but differing 18 miles in longitude, and 

 at Barlonee it occurs as an earth : as both places lie on the same 

 level, I have no doubt the stratum is continuous between them. It 

 occurs abundantly in the ghats, frequently discolouring the rivulets, 

 and giving a ferruginous character to the soil over a considerable 

 area. When thin, andunder heavy beds of basalt or amygdaloid, the 

 exposed edge of the stratum projects, is rounded, and double the 

 thickness of the stratum itself ; as if it had once been in a tenacious 

 fluid state, and squeezed out by the superincumbent basalt j such is 

 the case at Jehoor. 



Pulverulent Limestone.— Limestone is met with, in the Dukhun, only 

 in three states : pulverulent, nodular, and crystalline. The first occurs 

 in thin seams on the banks of rivers and water-courses and at the base of 

 hills in debris. The seams are from an inch to three feet in thickness, 

 covered by a few feet of black earth. Sometimes in whiteness it re- 

 sembles pounded chalk, and is then used by children to smear their 

 writing boards. 



In this state it occurs at Jehoor and Islampoor near Ahmednuggur. 



