'Transactions of the Bombay Geographical Society, from September 1850 to June 1852. Edited by the Secretary. Volume X.' [‎199] (332/458)

FRESH WATER BEDS.
199
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)' ock l»s besiiJ
mm beneatluiij
t has at one pointy
eration after tklJ
the zigzag %
The fossils iatfc
?hen the enginid
Mr Clark, Justi
aper, an essay m
' Branch oftlifil
1 H. J, Carter, fc
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respect. That A
mass of black tffi-
ee classes of r^' 1.
Auxuuy vyypnusQ prevailed throughout these
lacustrine deposits and in some parts strata were wholly composed of the shells of
these little animals : there were the remains of several species of them-Iona
ovoid and granulated on the surface, another cylindrical, and a third discovert
by Dr. Leith which had a striated rim round the large end. The author had also
found several small seeds and Dr. Leith again had discovered leguminous nod,
like those of the tamarind tree, with roots and stems of aquatic plants which
with pieces of vanous kinds of wood abound in the lower part of these strata in
a bituminized or anthracitic or coaly state, giving the whole a black carboniferous
character. No positive evidence of shells had yet been met with but
the author had found in a black chertified portion of the upper part
of these strata the section of a fossil which could hardly be takeri for
anything else but the remains of a shell resembling a Paludina. All this
proved that these strata were purely lacustrine, and hence it followed
that in the position now occupied by the island of Bombay, that is so far
as latitude and longitude are concerned, there was onee a river or fresh water lake •
but it by no means followed that this lake should have been on a level with the
sea, since the author had shown in his 4 IVlemoir on the Geology of the Southeast
Coast of Arabia’ that that shore at least of the Arabian Sea had undergone an
elevation and depression of more than 4000 feet. 6
“Next to the Lacustrine strata in interest, perhaps, was a rock which had been
called ‘ CoMglomerate, , 4 trap tufa,* &c. This appeared to be an igneous one, which
had been altered by its passage through aqueous strata and formations containing
much iron. The presence of large angular portions of aqueous strata proved this
and the heterogeneous admixture of igneous and aqueous rocks in the greater part
of it made it closely resemble in composition the Uothiiegendes of the New Red
Sandstone Series, also called 4 Exeter Conglomerate j’ while its argillaceous nature
in some parts, mottled red and white and always highly ferruginous allied it with
the foregoing characters so strongly lo the Laterite, that the author conceived
them to be one and the same formation. There had been two or more effusions of
it, because dykes of it were seen passing through masses of tlie same material;
the hills at the northern extremity of the island were composed of it: it might be
seen following the course of the lacustrine strata imbedded in the diorite, and
bursting through the latter in several places. ,,
43.—The yellow sedimentary beds continue traceable all along the
landward base of Worlee Hill by the public road, occasionally mani
festing themselves on the sea shore. A bold promontory of hard com
pact basalt runs out to seaward from the fishing village of Worlee :
just behind the fort, close by the beach, there are six or seven wells,
nearly adjoining to each other, all cat through the stratified rock—they
are all old and moss grown, and all I could determine of the strata
was that they dipped at an angle of from 10 ° to 12 ° nearly due
south. From this onward to the estuary at Mahim, the rock sinks
beneath the level of the sea, and is covered over by littoral concrete.
The basalt, as already stated, re-appears at Bandora, and forms the
Promontory and ridge of Nossa Senora de Monte. The rock to the
eastward ot this seems mostly tuffaceous, and is, very probably, the