The large supply of water found in the Island is remarkable,
there being, apart from the numerous small brackish springs which
occur on the outskirts and the low lands, no less than 212 fresh
water springs, yielding daily about 8000 tuns of the purest quality.
There is, indeed, scarcely a paddock or meadow without its spring
of the very clearest water. For such a bountiful gift to this Island*
while the neighbouring one of Ascension is entirely dependent upon
condensed sea water and collected rain water stored in tanks, I
think the difference in geological structure accounts. Clouds very
frequently envelope the high mountainous parts of both these
Islands, as they do at Madeira and the Canary group, though not to
so great an extent, and, except on those bright cloudless days
which sometimes occur, a condensation of moisture is taking place
night and day. The water thus deposited soaks into the soil, and,
flowing along the impenetrable upper surface of some substratum of
thick lava, finds its exit, where the edge of that stratum crops out, in
the form of a fresh water spring. Ascension appears to differ in this
respect; the lava strata do not exist in such broad massive sheets or
layers, but the whole formation partakes more of a cindery, scori-
aceous, and porous nature, so that whatever moisture is deposited
from the clouds on the mountain top penetrates vertically down
through the Island, and is not, as at St. Helena, arrested in its progress
by any solid strata.
The lava beds on the high land, where they have now passed
into a hard grey or whitish marl, are considerably perforated by
cylindrical holes, measuring from three-quarters to an inch in
diameter and two or three inches deep. These holes pass occasionally
into one another, and generally terminate in a conical form.
Upon close examination their interior surface shows a roughly-
grooved texture, the furrows running transversely round the sides,
plainly indicating the marks of some apparatus by which they have
been bored. In considerable numbers these perforations may be
seen along the roadside banks, in the neighbourhood of Joho’s Hole,
Green Gate, Hailey’s Mount, and very generally at the same
sphere at the time of examination. It is found to hold in solution a considerable quantity
of neutral salts, principally sulphate of magnesia, and is a mild and effectual cathartic. It
very nearly resembles the Bristol Hot Wells, hut is not so unpleasant to the taste and would
most probably be found equally useful in the cure of those diseases for which that celebrated
spring is used.” My failing to meet with this spring would not be altogether conclusive that
it does not now exist.
altitude of about 2000 feet above the sea. Mostly they are filled
with mud, and altogether present a very ancient appearance. I t
being contrary to all evidence that these rocks were ever in such
positions as to be bored by pholades, or.any creatures inhabiting
the sea, we may reasonably form the conclusion that the litho-
domous perforations which we now find in them have been made by
the great land snail of St. Helena, the Bulimus auris vulpina,
previous to its becoming extinct in the Island. This opinion is
strengthened by the non-existence of any other creature likely to
have bored them, as well as by the fact that a comparison of some
of the shells with the holes shows a very accurate correspondence.
Some additional force may also, I think, be derived from the fact
mentioned to me by Mr. Gwyn Jeffreys, that this extinct bulimus
must have lived in water or swamps, as well as on land. I t is true
that nothing like a lake or a swamp of any size now remains in the
Island, but there is no reason why, previous to its being so broken
up and drained by denudation, large ponds and swamps should not
have existed—indeed it seems most probable that they did, and also
that their edges or coasts "were formed of these very rocks in which
the perforations occur. The existence of so much moisture would
have greatly facilitated the passing of the lavas into felspathic
marls, and thus account for the large masses which occur in a
tumbled, displaced position from what they must originally have
occupied as strata.
The subsequent disappearance of swamps by drainage, as the
Island became smaller, would very probably account for the death
and extinction of this bulimus by depriving it of its natural element,
and perhaps also of its food, in some semi-aquatic plants, the
existence of which might also be brought to an end as the land
became drier.
I t is also not a little, remarkable that the dead bulimus shells are
now found on the north-eastern side of the Island, where, no doubt,
judging from the appearance of the land, swamps would have
existed at a moré recent period than at any other part.
The Island cannot be said to be rich in minerals, nothing having
yet bI eeTn di scovered of much commercial value. Pyrolu"site, or
black oxide of manganese, has been exported to Europe and obtained
a fair market price, but it is an ore of a hard description, and
difficult to separate from the clay-beds in which it occurs. This,