Lieut.-Colonel Sykes on a portion of Dukhun. 419 



at Seringapatam, which must have been propelled upwards, as it broke 

 through an oblique seam of hornblende in the sienite, and carried the pieces 

 up above the level of the hornblende vein* . " On the eastern coast," Mr. 

 Calder says, " from Condapilli northward, the granite is often penetrated 

 " and apparently heaved up by injected veins or masses of trap, and dykes of 

 " greenstone f ." 



Ferruginous Clay. 



The next distinctive feature is the occurrence of strata of red ochreous 

 rock, in fact, Mac Culloch's ferruginous clay underlying thick strata of basalt 

 or amygdaloid, precisely as is seen to be the case in the Giant's Causeway in 

 Ireland. It passes through every 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 amygdaloid^ near the source of the Seena river, indurated under basalt 

 at Kothool. Although hard, it is here so cellular as to have the appearance 

 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 300 to 600 feet of basalt. In the former 

 locality it is about three feet thick, in the latter 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 matter consists of very minute 

 crystals 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, and under 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. Such is the case at 

 Jehoor, and an illustrative specimen accompanies this paper. 



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 



* Physical Class, Asiatic Researches, part i. p. 22. 

 t Ibid., part i. p. 10. 

 VOL. IV. SECOND SERIES. 3 I 



