548 J. G. Malcolmson, Esq., on the Fossils of 



of the mass it affects the magnet. Not far from where this rock occurs, I collected specimens of 

 hornblende schist, leaving little doubt as to the ores being of the same nature, the former having 

 become altered in situ, in the same manner as some of the superficial strata at Deemdoortee are 

 seen to do, I therefore conclude, that the superior quality of the Nirmul iron depends on the 

 ore being a comparatively pure protoxide. It certainly is not dependent on the nature of the fuel, 

 which is much the same in both places*. Captain Herbert, indeed, long ago suggested, that the 

 superiority of the Gwalior iron over that principally worked in the Himalayahs, depended on the 

 former being a magnetic ore, like that of Sweden ; but the first accurate information on the sub- 

 ject was communicated by Dr. Royle to Mr. De La Beche, who states f, on the authority of that 

 gentleman, that magnetic iron ore is extensively diffused in hornblende slate in the central range 

 of mountains in India, and that it also occurs in the Himalayahs. This geological position corre- 

 sponds with that of the Nirmul ore; but the latter does not bear any resemblance, except in its 

 peculiar lustre, to the Menaccanite of Cornwall, to which it is compared by Mr. De La Beche ; 

 nor could I detect any titanium in it. With regard to the geological relations of the magnetic 

 iron ore, it is also necessary to observe, that in India it is not confined to the hornblende schist, 

 but is found extensively distributed in the granite and gneiss of the Carnatic and Mysore, in quartz 

 rock near the iron works of Porto Novo ; and, as has already been observed, associated with galena 

 in the diamond sandstone of Cuddapah. The discovery of a mineral, so generally confined to the 

 primary rocks, in the great sandstone formation, affords an additional argument in favour of the 

 opinion of those, who consider this rock and the subjacent schists, as equivalents to the older 

 European sedimentary formations, rather than to those of the supermedial order. 



Description of the Sichel Hills, and of the Freshwater Shells. 



Returning to the line of route, the granite, on approaching- to the Sichel 

 hills, hecomes softer and decomposes rapidly ; and the soil gradually changes 

 to the well-known black basaltic mould, known in India by the name of "^ cot- 

 ton ground," and, as usual, it is mixed with calcedonies, zeolites, &c. Amongst 

 these minerals were some fragments of a red colour, and considerable specific 

 gravity, though full of irregular cavities, and so like the slag of an iron fur- 

 nace, that I considered them to have had that origin, till I discovered a consi- 

 derable mass of a similar nature protruding from the granite and black soil by 

 which it was covered. Along with these fragments were others of a semivitri- 

 fied matter, containing small white crystals of felspar, and hardly to be distin- 

 guished from a piece of granite fused by Dr. Voysey in the steel furnaces of 

 the neighbouring district. The granite constitutes the surface rock a little 

 further, gradually passing into a black compact basalt, intermixed with many 

 white spots, apparently of felspar. The trap then becomes softer, forming- 

 small hills of a cellular amygdaloid, abounding in cavities lined with green 



* Iron, which has been ascertained to be superior, for many purposes, to the best German iron, 

 has been recently imported from the western coast of India ; but the mines from which it was ob- 

 tained have not been examined. Captain Jervis, of the Bombay Engineers, however, informs 

 me, that ores, powerfully affecting the magnet, exist in great quantity at Taygoor, a village of the 

 Koncan, not far from the port from which the iron in question was procured. 



t Manual of Geology, 3rd Edit., p. 435. 



