'Transactions of the Bombay Geographical Society, from September 1850 to June 1852. Edited by the Secretary. Volume X.' [‎174] (307/458)

174
©EOLGGY OF BOMBAY,
15.—At Chinchpoogly the greenstone once more rises into a fine bold
ridge, 'which attains the altitude of 150 feet at Parell Flagstaff, a n( j
. • _ 1 1. P ^ i-V./-, on-f* f Wrt YY111 f'SI W71 vf f ie, .1 il
continues unbroken for the space of two miles. Betwixt this and the sea
g* 1 ,
on the Harbour side, the ground undulates in three successive rid o ^
nearly parallel to each other, one overhanging the shore, and one be«
twixt this and that just described, the two last being broken and irregular.
Though the uniformity of the external aspect of these might lead to
the supposition that the structure of the rocks was the same through
out, this is far from being the case. The bolder and more elevated
portions of all the ridges consist of fine-grained compact greenstone,
with very few minerals imbedded. In the portion of the hill south
of the flagstaff, where the road crosses from Sewree to Parell, a
curious mass of tuffa intrudes itself ; externally, it is so blackened with
the weather as not to strike the eye as in any way differing materially
from the rocks around—when fresh broken, it is for the most part al
most white. It will he found more minutely described under trap
twffa. Each of the ridges rests on a series of strata full of organio
remains, and which, with the tuffas, occupy a very extensive
space betwixt the beds of trap. The Fort of Sewree is built
upon a mass of black rock, which might at first be readily
mistaken for basalt—it is, in fact, a Lydian stone, a black jasper
or chert, the result, most probably, of the action of the volcanic rocks
around on a stratified clay; bed : the strata are still traceable in
the midst of the fusion to which they have been subjected. A series of
flats, from which the sea is excluded artificially, and on which salt
is extensively made, here prevail, and the surface of the island seldom
at this place rises more than a few feet above high-water mark, and
generally bears obvious traces of submergence. A beautiful group
of litile hills make their appearance opposite the old artillery grounds,
Matoongn, and so continue to Sion, at the extreme end of the island.
The southernmost of these consists of the jaspideous rock, or chert, of
which Sewree Fort is composed,—the rest in general of various
descriptions of trap tuffa, with occasional exhibitions of greenstone.
THE CENTRE OF THE ISLAND.
16.—Betwixt the two sets of ridges just described—the
ridge from Malabar Point to Bassein, and the greenstone
# eo ’ is!er fl
Jis» lnl0stp
!> f , the ;
iit®i aft erffa _
recent, on
stjtions for t' 1(
(ii*inetotrs
fell beds, a ve
jacter or positio
(lough there is
stratified beds, J
11,-It is qi
titliin the hum
o( upheavals ai
instead of a sin,
lauds,
tion, if not
sillier three or
tiles effectual! 1
*
inti old MS. a
continuing whe
dilie Island,”
N and Bi
&l ] tunning o
inland; atl
causeway
admi
“Penings i
const!
into th
constru
•The n
iin § tin
hbour
k once
>ve,
5ro\
lit:
18,
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