The texture of the sandstone at the surface, where it comes in
contact with the basalt, has in some places been altered by it, but
in others it seems to have been as little changed as the habitations
of the people who were suffocated by the ashes of Vesuvius in the
city of Pompeii. I am satisfied, from long and careful examination,
that the greater part of this basalt, which covers the tableland of
Central and Southern India, must have been held for some time in
suspension in the ocean or lake into which it was first thrown in the
shape of ashes, and then gradually deposited. This alone can account
for its frequent appearance of stratification, for the gentle
blending of its particles with those of the sand near the surface of
the latter; and, above all, for those level steps, or tables, lying
one above another horizontally in parallel bars on one range,
corresponding exactly with the same parallel lines one above another
on a range twenty or thirty miles across the valley. Mr. Scrope's
theory is, I believe, that these are all mere flowing _coulees_ of
lava, which, in their liquid state, filled hollows, but afterwards
became of a harder texture, as they dried and crystallized, than the
higher rocks around them; the consequence of which is that the latter
has been decomposed and washed away, while the basalt has been left
to form the highest elevations.
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