lly
adapted for transposition by birds. Besides the albatrosses, various
species of Procellaria and Puffinus, birds which range over immense
distances may, I think, have played a great part in the distribution of
plants, and especially account, in some measure, for the otherwise
difficult fact (when occurring in the tropics), that widely distant islands
have similar mountain plants. The Procellaria and Puffinus in nesting,
burrow in the ground, as far as I have seen choosing often places where the
vegetation is the thickest. The birds in burrowing get their feathers
covered with vegetable mould, which must include spores, and often seeds.
In high latitudes the birds often burrow near the sea-level, as at Tristan
d'Acunha or Kerguelen's Land, but in the tropics they choose the mountains
for their nesting-place (Finsch and Hartlaub, _Orn. der Viti- und
Tonga-Inseln_, 1867, Einleitung, p. xviii.). Thus, _Puffinus megasi_ nests
at the top of the Korobasa basaga mountain, Viti Levu, fifty miles from the
sea. A Procellaria breeds in like manner in the high mountains of Jamaica,
I believe at 7,000 feet. Peale describes the same habit of _Procellaria
rostrata_ at Tahiti, and I saw the burrows myself amidst a dense growth of
fern, &c., at 4,400 feet elevation in that island. Phaethon has a similar
habit. It nests at the crater of Kilauea, Hawaii, at 4,000 feet elevation,
and also high up in Tahiti. In order to account for the transportation of
the plants, it is not of course necessary that the same species of
Procellaria or Diomedea should now range between the distant points where
the plants occur. The ancestor of the now differing species might have
carried the seeds. The range of the genus is sufficient."

[106] _Nature_, Vol. VI. p. 262, "Recent Observations in the Bermudas," by
Mr. J. Matthew Jones.

[107] "The late Sir C. Wyville Thomson was of opinion that the 'red earth'
which largely forms the soil of Bermuda had an organic origin, as well as
the 'red clay' which the _Challenger_ discovered in all the greater depths
of the ocean basins. He regarded the red earth and red clay as an ash left
behind after the gradual removal of the lime by water charged with carbonic
acid. This ash he regarded as a constituent part of the shells of
Foraminifera, skeletons of Corals, and Molluscs, [_vide_ _Voyage of the
Challenger_, Atlantic, Vol. I. p. 316]. This theory does not seem to be in
any way tenable. Analysis of carefully selected