to 250
feet above the sea-level, consisting of various kinds of limestone rock,
sometimes soft and friable, but often very hard and even crystalline. It
consists of beds which sometimes dip as much as 30deg, and which also show
great contortions, so that at first sight the islands appear to exhibit on
a small scale the phenomena of a disturbed Palaeozoic district. It has
however long been known that these rocks are all due to the wind, {265}
which blows up the fine calcareous sand, the product of the disintegration
of coral, shells, serpulae, and other organisms, forming sand-hills forty
and fifty feet high, which move gradually along, overwhelming the lower
tracts of land behind them. These are consolidated by the percolation of
rain-water, which dissolves some of the lime from the more porous tracts
and deposits it lower down, filling every fissure with stalagmite.

[Illustration: SECTION OF BERMUDA AND ADJACENT SEA BOTTOM.

The figures show the depth in fathoms at fifty-five miles north and
forty-six miles south of the islands respectively.]

_The Red Clay of Bermuda._--Besides the calcareous rocks there is found in
many parts of the islands a layer of red earth or clay, containing about
thirty per cent. of oxide of iron. This very closely resembles, both in
colour and chemical composition, the red clay of the ocean floor, found
widely spread in the Atlantic at depths of from 2,300 to 3,150 fathoms, and
occurring abundantly all round Bermuda. It appears, therefore, at first
sight, as if the ocean bed itself has been here raised to the surface, and
a portion of its covering of red clay preserved; and this is the view
adopted by Mr. Jones in his paper on the "Botany of Bermuda." He says,
after giving the analysis: "This analysis tends to convince us that the
deep chocolate-coloured red clay of the islands found in the lower levels,
and from high-water mark some distance into the sea, originally came from
the ocean floor, and that when by volcanic agency the Bermuda column was
raised from the depths of the sea, its summit, most probably broken in
outline, appeared above the surface covered with this red mud, which in the
course of ages has but slightly changed its composition, and yet possesses
sufficient evidence to prove its identity with that now lying contiguous to
the base of the Bermuda column." But in his _Guide to Bermuda_ Mr. Jones
tells us that this same red earth has been found, two feet thick, under
coral r