On the Tertiary Deposits, associated with Trap-rock, in the East Indies

I n introducing the following descriptions of some fossils from Peninsular India, I shall confine my remarks to the rocks, volcanic and sedimentary, with which those fossils are connected. They have already been noticed in a memoir, which, in conjunction with my friend the Rev. R. Hunter, I submitted to the Society in 1854. On that occasion I endeavoured to prove that there was no foundation “for the supposition that the great outpouring of basalt in India took place in the ocean,”—that the water of the lake in which it really was effused was in many places “so shallow as to allow the igneous rock to rise above its surface into the atmosphere,” and that therefore the flatness of the tops of trap-hills was not owing to superincumbent pressure, as is generally believed, but was “the effect of the well-known law by which the surface of liquid bodies is reduced to the same uniform level.” The age of the deposit formed at the bottom of the lake, before it was invaded by the volcanic eruption, I considered to be Lower Eocene; and, while inferring as a matter of course that the overlying trap was subsequent to it, I expressed the opinion that the similar rock which was frequently found underlying was more recent than both. In opposition to this last view it is held, that the underlying trap must have been poured out first, and the freshwater deposit formed over it. This, I admit, would be the theory attended with the