274 Notes upon the Geology of the BajtnaTial Hills. [No. 3. 



a remarkable vesicular, and concretionary conglomeritic rock, highly 

 ferruginous, and in many places so charged with peroxide of iron 

 that it can be used as an ore of iron. It frequently stands up in 

 high, steep, and boldly projecting cliffs, and though traversed by 

 many joints is so coherent, that it breaks off in huge masses of 

 many hundred cubic feet, found at lower levels on the hill sides, 

 while the smaller, more broken and more rounded masses, are 

 scattered over the surface of the country. This curious rock is in 

 some cases associated with and passes into irregularly bedded hard 

 ferruginous sandstones, but generally speaking the whole thickness 

 is of the conglomeritic structure noticed above. In it occur, sharply 

 angular as well as rounded (slightly) pieces of sandstone shales, 

 pebbly grits, &c. all identical with those which occur in situ beneath 

 it in the series. Many of these are derived from the altered shales, 

 and sandstones below the trap. The general aspect of this rock 

 when weathered, is exceedingly rough and scoriaceous ; but on a 

 fresh fracture the mass has all the concretionary semi-crystalline 

 semi-vesicular aspect of the well known nodules of kunkur. In a 

 few cases it is calcareous as well as ferruginous, and then the re- 

 semblance is even more striking. It is in fact an iron-tufa due to 

 similar causes, and presenting exactly the same general character, 

 as ordinary calcareous tufa, save that it is ferruginous instead of 

 calcareous.* 



Along the flanks of the hills many detached, and in some cases 

 rich, deposits of kunkur occur, which are however no where worked 

 for lime. At Sukri-gully on the banks of the Ganges, where this 

 kunkur occurs in a tolerably regular bed, in addition to the 

 detached concretionary nodules and strings disseminated through 

 the red stiff clay which overlies it, it is worked to some extent for 

 the manufacture of lime. The same deposit under precisely similar 

 circumstances, shews at the projecting point on the Granges near to 



* This is the rock called Laterite in Capt. Sherwill's papers and Dr. MacClelland's 

 reports. It were well that this term (laterite) were either abandoned altogether, 

 or were more strictly denned in its application. It has been used as applying to 

 rocks so altogether distinct both in character and age, that it is useless as a defi- 

 nitive term, and its Original application to a clay has been quite forgotten or 

 overlooked. 



