'Transactions of the Bombay Geographical Society, from September 1850 to June 1852. Edited by the Secretary. Volume X.' [‎188] (321/458)

188
GEOLOGY OF BOMBAY.
with in Mahim Wood, and in most of those under the western portion
of the Esplanade, the same as at Sewree ; as also alons* the line of tbs
Grant Road, and so to Juggonath Sunkersett’s house: it crops out
under the sands betwixt the rocks in the upper part of Back Bay and
the Sanitarium : it is found forming the rice fields betwixt Mafcoonga
graveyard and Sion, transformed into the ordinary brown earth of our
higher grounds, and recognisable chiefly from the tubes which indicate
the former existence of mangrove roots.
32. Whenever the excavations in the places enumerated are first
made, a very powerful effusion of sulphuretted hydrogen gas is emit
ted,—so much so at times, as to taste the water and taint the air around,
I have met with no good section near Sion, or in the higher portion
of the Flats betwixt the Club and Love Grove, but the kunkur and the
tubes abound on the surface in both of these localities : I have no
doubt the arrangements are the same. When tolerably free of salt,
the blue clay, as in the case of that under the esplanade, answers for
pottery purposes, but it shrinks greatly, and is apt to warp in drying
—it burns into a dirty yellowish red. When much contaminated
with salt, as is the case of that in the flats, it is most difficult to
sweeten it : I have washed specimens of it in a tub for the whole
course of a monsoon, and to the last found the water with which it
was washed slightly salt to the taste. When thrown or moulded in
this state it promises admirably, and turns when green like fine horn—
the moment it is further dried it crumbles to pieces.
-A.
33. —Along the line of the railway, betwixt Mahim Road and Sion,
the concrete is awanting—the blue clay extends from the surface
down to the rock. The Lagoon formation, or newer clay, covers the
fractured portion of the mangroves, here penetrating to the depth of
from one to two feet, the railway cuttings furnishing excellent
exhibitions of both. Here selenite is found in abundance, ffili D £
up in plates the cracks of the clay. The plates are generally
oval, thinning out at the edges all round—sometimes they a re
lenticular : they vary in size from an inch to four inches in thek
larger, and about half as much in their smaller, diameter, and ft° m
one-sixteenth to half an inch thick. Externally they are rough and
earthy, of a greenish or yellowish brown tint : when held up befcwW
the eye and the light, a beautiful feather-like object makes its
iltlie plate, or
rfmetin with
loinbay; they
le selenite, lik
sly explainec
tompose the
tflioie or seleni
31,-In cuttii
anted from tl
ilward of th
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'% of Matoc
w shores. Th
^ adhering f
la weight,
Stare as a
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