Records of the Geological Sane// of hulia. 
[vol. v. 
92 
a plane. Had tliis surface, thus formed by the action of rain and rivers, been depressed 
beneath the sea before being covered up by trap, some traces of marine deposits must in 
places have remained at the base of the volcanic rocks conformably underlying them. But 
nothing of the kind occurs. The Lameta beds are of freshwater origin, and the Bagh 
beds, which are marine, afford evidence of having been raised above the sea and acted upon 
by streams and rain before the lavas overflowed them. Now, the bottom flows are frequently 
some of the most compact and crystalline met with; they are as widely spread and as 
horizontal as any of the others. The same is the case in Bombay Island with the topmost 
flows; the basalt of Malabar hill, which rests on the freshwater shales seen at its base, is 
perhaps the most compact and most clearly stratified flow in the island, and that it must 
originally have been horizontal from Valukeshwar to Waiii, upwards of four miles, is evident, 
for it l'ests conformably everywhere throughout that distance on the sedimentary beds. If 
then the rocks at the base of the series throughout a large area, and those at the top at 
Bombay, arc of subaorial origin, and these beds are as compact, as crystalline, and as distinctly 
stratified as the intermediate flows,-if, in short, there is no lithological distinction between 
the flows which are proved to have been poured out on the land and the groat mass of the 
bods,-it is surely illogical to assert that the traps in general are submarine without adducing 
any other argument than their lithological characters. 
The whole thickness of the traps cannot be less than 5,000 feet, probably it is more. 
The time occupied in their accumulation must have been groat, for the sedimentary beds 
intercalated prove large poriods of repose, during which lakes were formed and became stocked 
with living animals; and it is impossible to say how much of the interval between the Middle 
Cretaceous and the Eocene epochs was occupied in their formation. As before stated, they 
rest upon the B;igh beds, which are of Tipper Greensand age; while upon them, after a break 
marked by great denudation, rest the Nummulitics, which are Eocene. 
So far as physical evidence is concerned, the break at the base of the traps in the Nar¬ 
bada valley appears less than that which separates them from the overlying Nummulitics near 
Surat. In Kachh, a group of ferruginous clays intervenes between the traps and the 
Nummulitics. For these reasons I am myself disposed to look upon the lower traps at least, 
and consequently on the freshwater beds of the Narbada valley aud Nagpur, as probably Cre¬ 
taceous. But most geologists are inclined to class the whole of the volcanic series as Eocene. 
The traps cover the whole of the Bombay Presidency from the Narbada river as far 
south as the parallel of Goa in the neighbourhood of Belgaon and Kaladghi. North of the 
Narbada in the Rewa Kanta they occupy but a small area ending abruptly south of Chota 
Udepiir. Powagarli hill is an isolated mass; and there is a larger tract composed of them 
around Dewad. A belt of them extends partly across Kattiawar, and another, five to ton miles 
broad, throughout the greater part of Kachh, the dip being to the south. Traces may 
perhaps bo detected farther to the westward, as at Ranikot in Sind, but no absolute proof of 
their existence has been found. 
Intertmppean beds .—To these reference has jnst been made. The most important are 
limestone, calcareous shale, chert, and more rarely sandstone, containing in abundance remains 
of plants and freshwater shells, the most common being Physa, Lymnea, Paludina, Mela¬ 
nia, JJuio, &c. The bods containing these fossils have not hitherto been found more than 300 
or TOO feet above the base of the traps. Each bed can rarely be traced for a longer distance 
than three or four miles, and seldom exceeds 2 to 3 feet in thickness; but successive beds are met 
with, trap flows intervening, sometimes as many as three sedimentary intercalations being 
met with one above the other, and often difi'ering from each other in mineral composition and 
in the fossils contained. That these beds have been deposited upon the underlying trap, and 
that the overlying flow has been poured over them, is clear, because the upper surfaces of the 
freshwater bands are always hardened and altered (though sometimes to a very slight degree) 
and their base is unchanged. 
