t 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 seaweeds 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 narrow crevices; and when thus fixed, it
required great force to remove them. At other times they darted
tail first, with the rapidity of an arrow, from one side of the
pool to the other, at the same instant discolouring the water with
a dark chestnut-brown ink. These animals also escape detection by a
ver