who made out[2] that the residuum of the melted ice consisted for the
most part of the silicious cases of diatomaceous plants, and of the
silicious spicula of sponges; while, mixed with these, were a certain
number of the equally silicious skeletons of those low animal organisms,
which were termed _Polycistineoe_ by Ehrenberg, but are now known as
_Radiolaria_.

[Footnote 2: _Ueber neue Anschauungen des kleinsten nördlichen
Polarlebens_.--Monatsberichte d. K. Akad. Berlin, 1853.]

In 1856, a very remarkable addition to our knowledge of the nature of the
sea bottom in high northern latitudes was made by Professor Bailey of
West Point. Lieutenant Brooke, of the United States Navy, who was
employed in surveying the Sea of Kamschatka, had succeeded in obtaining
specimens of the sea bottom from greater depths than any hitherto
reached, namely from 2,700 fathoms (16,200 feet) in 56° 46' N., and 168°
18' E.; and from 1,700 fathoms (10,200 feet) in 60° 15' N. and 170° 53'
E. On examining these microscopically, Professor Bailey found, as
Ehrenberg had done in the case of mud obtained on the opposite side of
the Arctic region, that the fine mud was made up of shells of
_Diatomacoe_, of spicula of sponges, and of _Radiolaria_, with a small
admixture of mineral matters, but without a trace of any calcareous
organisms.

Still more complete information has been obtained concerning the nature
of the sea bottom in the cold zone around the south pole. Between the
years 1839 and 1843, Sir James Clark Ross executed his famous Antarctic
expedition, in the course of which he penetrated, at two widely distant
points of the Antarctic zone, into the high latitudes of the shores of
Victoria Land and of Graham's Land, and reached the parallel of 80° S.