the coast, and at the height of about forty-five feet above the water.
Upon examination this white stratum is found to consist of calcareous
matter with numerous shells embedded, most or all of which now exist on
the neighbouring coast. It rests on ancient volcanic rocks, and has
been covered by a stream of basalt, which must have entered the sea
when the white shelly bed was lying at the bottom. It is interesting
to trace the changes produced by the heat of the overlying lava, on the
friable mass, which in parts has been converted into a crystalline
limestone, and in other parts into a compact spotted stone. Where the
lime has been caught up by the scoriaceous fragments of the lower
surface of the stream, it is converted into groups of beautifully
radiated fibres resembling arragonite. The beds of lava rise in
successive gently-sloping plains, towards the interior, whence the
deluges of melted stone have originally proceeded. Within historical
times, no signs of volcanic activity have, I believe, been manifested
in any part of St. Jago. Even the form of a crater can but rarely be
discovered on the summits of the many red cindery hills; yet the more
recent streams can be distinguished on the coast, forming lines of
cliffs of less height, but stretching out in advance of those belonging
to an older series: the height of the cliffs thus affording a rude
measure of the age of the streams.
During our stay, I observed the habits of some marine animals. A large
Aplysia is very common. This sea-slug is about five inches long; and
is of a dirty yellowish colour veined with purple. On each side of the
lower surface, or foot, there is a broad membrane, which appears
sometimes to act as a ventilator, in causing a current of water to flow
over the dorsal branchiae or lungs. It feeds on the delicate sea-weeds
which grow among the stones in muddy and shallow water; and I found in
its stomach several small pebbles, as in the gizzard of a bird. This
slug, when disturbed, emits a very fine purplish-red fluid, which
stains the water for the space of a foot around. Besides this means of
defence, an acrid secretion, which is spread over its body, causes a
sharp, stinging sensation, similar to that produced by the Physalia, or
Portuguese man-of-war.
I was much interested, on several occasions, by watching the habits of
an Octopus, or cuttle-fish. Although common in the pools of water left
by the retiring tide, these animals were not easily caught. By means
of their long arms and suckers, they could drag their bodies into very
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