'Transactions of the Bombay Geographical Society, from September 1850 to June 1852. Edited by the Secretary. Volume X.' [‎180] (313/458)

GEOLOGY OF BOMBAY.
crystalline, the material excavated from the Dhobee Tank in April and
May 1851 being to the depth of twenty feet continuously* crystallised
throughout. To the eastward again of the Wellesley Monument, and
all along from the Cooperage to Malabar Hill, within from 100 to 200
yards of the shore, the material is perfectly loose from the surface
down : it abounds in fresh water, and notwithstanding the porousness
of the soil, is favourable for the purposes of cultivation.
26. In excavating two large wells near the Wellesley Monument,
the shell gravel was found to extend down eighteen feet, to the trap;
the lower beds being of sand^were being dug through, when the water
flowed so freely at the dryest part of the season that it materially in
terrupted the work. Here large masses of coral were found, such as is
now growing in Back Bay : it occupied the position in which it
grew, and had neither suflered from decomposition, mineralization, or
abrasion. This variety of coral never appears on our shores as a rock,
for having attained the thickness of six or eight inches, and an area of
a square foot or two at the outside, the zoophyte seems to die, and the
stony covering to become detached. On this the coral almost
immediately becomes abraded and worn, and is found in rolled masses
on the beach. The inference from the condition of the coral found
under the shell gravel on the Esplanade, is, that it was suddenly sub
merged, and at once buried so deep in sand and gravel that it was be
yond the reach of further injury : how the water which pervades the
whole shelly and arenaceous beds in Bombay should within such narrow
limits be possessed of such different properties—crystallising the shells
at one place, and filling up their cavities into a solid crystalline mass, and
leaving the whole gravelly mass unaffected in others close by,—is not
easily explained.
27. —Where the shells are generally cemented and mixed with ar
gillaceous matter, as for example where the railway cuts through
road opposite Mahim Wood, and again near Sewree Fort, the formation
becomes exceedingly hard and compact, with an earthy 7 in place of a
crystalline appearance.
28. — Where found, —'The formation, the peculiarities of which have
thus minutely been described, first makes its appearance on the s ea
shore south of the Lighthouse, and forms the graveyard at th®
* See Bepoits of th« Society for April, p. sir.
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