part 2.] Wilkinson: Geological Structure of Southern KonJcan. 45 
is vesicular, the cavities being filled by quartz, &c. The soft laterite soil above hardens on 
exposure and this rapidly. It is very thick here and along the sea coast, trap only becoming 
disclosed in the deep sections and at the base of the cliffs. In proceeding inland, however, 
it is found higher up in the hills, which seems to show that it has a westerly dip, though it 
is very difficult to determine the amount, as all the sections are so covered by the detritus 
from the laterite. East of Rutnagherry, the latter rock extends for about, fifteen or twenty 
miles; beyond this the trap hills are more irregular in outline and increase gradually in 
height towards the ghats. The eastern boundary of the laterite runs west of Lanje in a 
south-east direction, passing east of Iiajapur to IChareputtun. South of the latter place its 
direction has been more correctly determined. 
About Phonda it is found nearer to the ghats than in other places, it then bears to 
the south-west, meeting low trap hills which run out from the ghats at the north of the 
Sawunt Waree state. The lower beds of this pass under it about half way between the ghats 
and the sea. South of this the width of the formation becomes much less, and it extends 
as a hand ten or fifteen miles wide along the western boundary of the state and in the 
narrow strip of British territory by Yingorla, &c. 
It occurs in great quantity in the Goa territory. In speaking of the laterite boundary, 
I refer to that of the plateau which has a very constant elevation, and consists, as I have 
mentioned, of a series of flat-topped or slightly undulating hills separated from one another 
by deep ravines, which have been excavated by the rivers which drain the country. 
There are numerous instances where this rock occurs farther east, forming patches which 
in many cases may he outliers of the great mass, though ofteuer occurring at a lower level, 
being the products of the denudation of the older laterite. These often have the appear¬ 
ance of true laterite, but are more generally found as gravel, sandstone, conglomerate, &c. 
The country east of the laterite boundary is more varied in aspect. The rivers rasing 
in the ghats run westward between lofty spurs for some miles, and then emerge into lower 
and more open country, which continues up to the scarped edge of the laterite hills. These 
spurs in the northern part of the district consist entirely of trap, the lines of flow of the 
beds in them being generally easily traceable, and merging at their eastern extremity into 
the main range of the ghats. These beds having been irregularly denuded, the result Is, 
that conical peaks have been left, which vary the otherwise even outline of the hills. These 
peaks are generally surmounted by a sharp black point of rock. A good example of this 
occurs iu a spur south of Phonda which runs out westward from the ghats. In the peaks 
on this, portions of a thick bed of black columnar basalt are seen, the bed of which these 
are outliers being very conspicuous in the ghats themselves. 
The metamorphies, &c., skirting the southern boundary of the trap are at a low level 
generally. The rock immediately under the trap is a white, yellow or pink altered sand¬ 
stone, associated with shales and lying unconformably on the older metamorphic rocks. 
The evidence tends to show that this sandstone formation was originally much thicker, 
hut it was much reduced by denudation before the outpouring of the trap, and this thinning 
has subsequently been carried on still further by other denudation affecting both it and 
the overlying rock. 
About Phonda and the country to the west, this sandstone (quartzite) is well seen, form¬ 
ing an open patch ot country about ten square miles in area and enclosed within the trap 
boundary, this rock with the exception of one or two isolated masses having been entirely 
denuded. 
