70 
liecords of the Geological Survey oj Imha. 
[voL. xiir. 
from Mr. Maloolmson, both very competent geologists, that even Bombay and I 
Salsotte had not been geologically examined, and that little was known of their I 
details and still less of those of the Konkan on the opposite side of the harbour. | 
Feeling much interest in the subject, I determined, while visiting the Island and 
the main land for other purposes, to pay what attention I could to the geology 
I began with Bombay, and spent some time in laying down the clip and direction 
of its rooks, which I found to be mostly igneous, traps and green.stones, with j 
occasional intervening bods, probably of sedimentary origin, all dipping more 
or less westward at a high inclination. While thus engaged I was fortunate ^ 
enoun-h to fall in with a bed, newly uncovered, containing very perfect remains | 
of batrachians, which lay immediately beneath a sheet of basalt capping the 
western side of the Island of Bombay, and which was evidently its latest forma¬ 
tion. I sent home to the late Dean Buckland some specimens of the fossils, 
which were figured in the Journal of the Greological Society (Vol. Ill, p. 224), 
and thus the o-eological date of the basalt was established. I found the same 
dip and bearing to prevail in Salsette. ' 
On reaching the Konkan, and pausing near Kalian, I was much struck with 
the difference between the outline of the eastern and western eminences. The 
hills of Salsette were sharp-topped and steep, all their lines more or less inclined 
and covered to the top with vegetation, whereas the hills, or rather mountains, 
of the Konkan, were flat-topped, their leading lines horizontal or nearly so, their 
sides terraced, the terraces divided by cliffs, and the tops, at least, bare of vege¬ 
tation. It seemed as though in the one case the bods, being tilted, had allowed 
the rain to penetrate and produced disintegration, while in the other, the beds 
being flat, resisted penetration and its consequences. It was also clear that the 
eastern mountains, as Towlee, Bhow-mulling, and Matheran, were outliers from 
the great mass of the Western Ghauts, strictly conformable to them in their struc¬ 
ture, and that the dip of their beds, so slight as to appear locally horizontal, 
was really towards the east, and with a remarkably uniform inclination. 
This contrast, obvious at the first glance, led me to suppose that the origin of 
the traps must bo sought for either in the trough of Bombay hai'bour or in the 
adjacent margin of the Konkan, or wherever the beds dipped from a centre or 
central line. It was further evident, with so complete a correspondence between 
the beds of the outliers and the main range, that the whole must at one time 
have been continuous, and that a vast mass of intervening matter must have 
been excavated and removed. 
Following out these ideas, I proceeded to examine the floor of the Konkan, at 
first along its western edge towards Panwell, and then more minutely along a 
line which pointed westwards from Kalian towards the great bay of the Malsege 
Ghaut, and which presented some very remarkable appearances. 
The rock beds, so far as I observed, at or near the level of the floor of the 
Konkan, which was not much above that of the sea, were all of a uniform variety 
of trap, and all amygdaloidal, the vesicles being mostly filled with zeolite. 
Usually the lower part of each bed was more or less solid, and the upper part 
vesicular. The vesicles were of all sizes, up to a length of 12 or 13 inches and a 
diameter of 3 or 4, and they were frequently elongated, as though the trap. 
