PART 3.] 
Blanford: Geology of Bombay Presidency. 
93 
In tlie Bombay Presidency, the only known localities for these “ Pliysa beds, ” as they 
have been called from the prevalence of that shell (they are the Tdkli beds of 11 islop), are near 
Dewad (Dohud) in the Kewa Ivanta (Rogers, Quart. Jour. Geol. Soc., 1870, p. 118,) and in 
Western Kachh, where they have recently been found by Mr. Redden, of the Geological Survey, 
and near Kaladghi, where Mr. Foote, of the Geological Survey, discovered a thin bed of 
sandy marl lying beneath the lowest trap flow and the gneiss. 
Near Gokak, in Belgaou district, Mr. Foote found fossil TInios in a thin bed of sandstone 
resting on a flow of amygdaloidal trap, which forms locally the base of the trap series, 
and was poured out over the rugged surface of the gneiss. The sandstones overlap the 
amygdaloid bed in places, and rest directly on the gneiss. 
The intertrappean beds of Bombay belong to a very different horizon, being intercalated 
with the very highest trap flows hitherto explored, aud their fossils are distinct, with one 
exception (a species of Cypris), from those found in the lower group of sedimentary deposits. 
The Bombay intertrappeans are composed of shale, and are of freshwater origin, as is proved 
by their containing frogs, freshwater tortoises,* Cyprides, remains of insects, and land plants. 
As in the group near tho base of the traps, there are in Bombay several successive deposits 
with lava-flows intervening. They have been traced into the island of Salsette, but not 
farther, probably for want of searching for them. 
The origin of these freshwater deposits is easily conceived. Flows of lava spreading- 
over an uneven land-surface, cut into hills and valleys by subaerial denudation, must have 
dammed up the valleys of streams and converted them into lakes. Other (lows might fill up 
the first lakes, but by isolating fresh hollows would produce fresh ones, for the flows, however 
liquid, could not have presented an absolutely plane surface, and the outbursts from different 
foci must have crossed and dammed up the hollows between flows from tho same crater. 
The absence of sedimentary beds in the centre of the series may be due to the greater rapi¬ 
dity of deposition or to the peculiar climate produced by the wide spread of volcanic out¬ 
bursts and to want of rain. 
It is rather singular that fossils should be so much more common in the beds intercalated 
with the traps than in the Lametas at their base, although such shells as have been found in 
the latter are apparently similar to those met with in the former. 
The traps and their associated beds have been treated at somewhat greater length than 
the other rocks on accoirnt of their great importance in Bombay, and the remarkable geolo¬ 
gical interest attaching to them. 
V.— Older Tertiary Series. 
Tho last of the great rock systems in ascending order is far less thoroughly known than 
most of those lower in the series. Although the abundance of organic remains found in it, 
foraminifera, corals, echiuoderms, and mollusca in the lower beds, and bones of vertebrata in 
the higher, have attracted attention, not only in India, but amongst tho paleontologists of 
Europe, very much remains to bo done before the sequence of beds and their faunae can be 
said to be properly known. It has been pointed out, and with every appearance of probabi¬ 
lity, that tho fossil forms from Sind described in the “ Description des animaux fossiles du 
groupe nummulitique de 1’ Iude” by M. M. D’Archiac aud Haime must have been derived 
from formations varying to a considerable degree in age, and it is highly probable that a 
thorough examination of the Sind rocks will show the necessity of sub-dividing them to a far 
greater extent than has hitherto been attempted. 
* The frog named liana pitnlhi bj Owen haB been shown by Dr. Stoliczka to be an Oxgglatms. The tortoise 
named Testudo LeitiH by Dr. Carter is not a Testudo (as indeed has been shown by Dr. Carter), but belongs to 
Emys or some allied genus. 
