44 
Records of the Geological Survey of India. 
[vol. n r . 
burnished surfaces which traverse the rock might seem to indicate the former cause and 
in appearance certainly resemble the ‘ slieken sides’ in a coal shale, but the peculiar arrange¬ 
ment of the steatite amygdala and their enveloping layers of quartz strongly contra indicates 
this idea, as there is no crushing or subsequent re-cementing of these brittle quartz layers, as 
would be seen if the burnished surface of the included nodules were due to pressure. Pres¬ 
sure has then nothing to do with the production of the smooth surfaces traversing the finer 
sorts of the steatite and displayed on the surface of its nodules, and the phenomenon is due 
to some peculiar form of segregative action whereby the nodules themselves originated from 
the finer portions of the adjacent rock. I think I am warranted in regarding this stea¬ 
tite as a mineral species, although it sometimes exhibits a passage into a form to which that 
term might he less applicable. Some of the largest lumps of the compactor variety of the 
mineral are pale grey distinctly tinged with pale yellowish or leek-green, or perhaps rather 
green than grey, lustre rather waxy, and decidedly tough, especially in a direction across 
the polished foliation planes which are rarely absent in the mass. 
The serpentine is everywhere very uniform in appearance, but in some spots, as west 
of La.idi, a rock is associated with it like an ordinary greenstone. I think it not quite 
certain that this rock is not an altered one, or if not a bedded rock or shale altered, I should 
regard it as a variety of serpentine produced by the reaction of the bedded rocks on it; 
my reason for so judging being the trifling and insignificant development of it, its obscure 
relations and the unlikelihood of a mere patch of rock of this character appearing here and 
there in the merest indications, if not a part of, and subordinate to, the general serpentine 
effusion in the neighbourhood. Nowhere else does this trap rock appear as an inde¬ 
pendent formation, but merely here as a very feebly developed satellite of the widely diffused 
Serpentine. 
Sketch of Geological structttbe of the Southern Konkan, by C. J. Wilkinson, 
Esq., late of the Geological Survey of India. 
The South Konkan is in its northern part composed of trap rocks, covered to a varying 
distance from the sea by laterite. Where the latter rock is present it gives a monotonous 
aspect to the country, forming an undulating and in some places quite flat plateau, the sur¬ 
face of which is a sheet of rock, black and slag-like externally. This laterite plateau, which 
has a general elevation of between two and three hundred feet, has a bare black appearance, 
supporting no vegetation, except scanty grass and stunted trees here and there. There are 
places where the rock has been denuded, and here owing to the presence of thicker soil, the 
ground can he cultivated. 
It is cut through by numerous rivers, the largest of which rise in the ghats, and after 
(lowing through comparatively open trap country, enter the laterite through deep ravines, 
which widen towards the sea, the rivers becoming broad tidal creeks. In these ravines, 
along the banks of the rivers, villages are generally situated, and every available spot of 
the rich alluvial soil is cultivated for the production of rice and other grain. At the sea 
coast the laterite forms bluff cliffs, in the lower part of which trap is disclosed. 
At Rutnagherry, &c„ in well and other sections, the trap is found to be overlaid by a 
thickness of a few feet of white clay, imbedding fruits and containing thin carbonaceous 
seams composed for the most part of leaves. This is separated from the soft laterite above 
by a ferruginous hand about an inch thick, having much the appearance of Haematite. It 
