falls, and even then it is irregular; but the clouds generally hang
low. Hence, whilst the lower parts of the islands are very sterile,
the upper parts, at a height of a thousand feet and upwards, possess a
damp climate and a tolerably luxuriant vegetation. This is especially
the case on the windward sides of the islands, which first receive and
condense the moisture from the atmosphere.
In the morning (17th) we landed on Chatham Island, which, like the
others, rises with a tame and rounded outline, broken here and there by
scattered hillocks, the remains of former craters. Nothing could be
less inviting than the first appearance. A broken field of black
basaltic lava, thrown into the most rugged waves, and crossed by great
fissures, is everywhere covered by stunted, sun-burnt brushwood, which
shows little signs of life. The dry and parched surface, being heated
by the noon-day sun, gave to the air a close and sultry feeling, like
that from a stove: we fancied even that the bushes smelt unpleasantly.
Although I diligently tried to collect as many plants as possible, I
succeeded in getting very few; and such wretched-looking little weeds
would have better become an arctic than an equatorial Flora. The
brushwood appears, from a short distance, as leafless as our trees
during winter; and it was some time before I discovered that not only
almost every plant was now in full leaf, but that the greater number
were in flower. The commonest bush is one of the Euphorbiaceae: an
acacia and a great odd-looking cactus are the only trees which afford
any shade. After the season of heavy rains, the islands are said to
appear for a short time partially green. The volcanic island of
Fernando Noronha, placed in many respects under nearly similar
conditions, is the only other country where I have seen a vegetation at
all like this of the Galapagos Islands.
The Beagle sailed round Chatham Island, and anchored in several bays.
One night I slept on shore on a part of the island, where black
truncated cones were extraordinarily numerous: from one small eminence
I counted sixty of them, all surmounted by craters more or less
perfect. The greater number consisted merely of a ring of red scoriae
or slags, cemented together: and their height above the plain of lava
was not more than from fifty to a hundred feet; none had been very
lately active. The entire surface of this part of the island seems to
have been permeated, like a sieve, by the subterranean vapours: here
and there the lava, whilst soft, has been blown into great bubbles; and
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