[2] A man, if he have good nerve, may hang over the summits,
and suspend in his hand a plummet that shall reach the bottom.
I should mention that this tableland is not only intersected by
ranges, but everywhere studded with isolated hills rising suddenly
out of basins or valleys. These ranges and isolated hills are all of
the same sandstone formation, and capped with basalt, more or less
amygdaloidal. The valleys and cappings have often a substratum of
very compact basalt, which must evidently have flowed into them after
these islands were formed. The question is, how were these valleys
and basins scooped out? 'Time, time, time!' says Mr. Scrope; 'grant
me only time, and I can account for everything.' I think, however,
that I am right in considering the basaltic cappings of these ranges
and isolated hills to have once formed part of continued flat beds of
great lakes. The flat parallel planes of these cappings,
corresponding with each other, however distantly separated the hills
they cover may be, would seem to indicate that they could not all
have been subject to the convulsions of nature by which the whole
substrata were upheaved above the ocean.
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