26 THE GEOLOGY OF BERMUDA. 
substances, chiefly peroxide of iron and alumina, silica, and some earthy 
phosphates. Now these substances are to a very small degree soluble 
in water charged with carbonic acid; consequently, after the gradual 
removal of the lime, a certain sediment, a certain ash, as it were, is left 
behind. One per cent. seems a very small proportion, but we must. 
remember that it represents one ton in every hundred tons of material 
removed by the action of water and of the atmosphere; and the evi- 
dences of denudation on a large scale are everywhere so marked, that, 
even were some portion of this 1 per cent. residue further altered and. 
washed away, enough might still be left to account fully for the whole 
of the red earth.”* Assuming the “red earth” to be the insoluble resi- 
due left by the solution of the major part of the calcium carbonate of 
the coral rocks, it should be observed that its materials doubtless have 
the same twofold origin which has been recognized in the case of the 
somewhat analogous red clays of the deeper parts of the ocean bottom. t+ 
They are doubtless in part derived from the minute quantity of non- 
calcareous mineral matter existing in the corals, shells, and other cal- 
careous skeletons of marine animals and plants; in part from the 
decomposition of volcanic minerals, which are continually being trans- 
ported in various ways to all oceanic islands. Analyses of samples of 
the ‘‘red earth” are quoted by Thomsont from a “‘ Report from Professor 
Abel, F. R. S., to H. E. General Lefroy, C. B., F. R.S., on the Character 
and Composition of Samples of Soil from Bermudas.” 
PHENOMENA RESULTING FROM UNEQUAL HARDENING OF THE LIME- 
STONE. 
A number of interesting phenomena result from the unequal hardening 
of the sand-rock where vegetable stems or roots or other accidents have 
determined the location of channels for the percolating waters. On the 
weathered surface of cliffs and banks of the drift-rock may often be ob- 
served hard bodies somewhat projecting, consisting of a more firmly con- 
solidated sand-rock, having the form of slender cylinders irregularly 
branching, the main trunks being generally nearly vertical. These stems 
may generally be seen to be tubular, and in the slender cavity may gener- 
ally be found more or less of woody fiber. These bodies have much the 
form and aspect of the “ branched bodies” observed by Darwin at King 
George’s Sound on the south-west coast of Australia, and at the Cape of 
“Thomson, op. cit., Vol. I., pp. 294, 295. 
t Thomson, op. cit., Vol. I., pp. 215-218; Vol. II., pp. 255, 256. 
t Op. cit., Vol. I., pp. 325, 326. 
