1G4 
THE VOYAGE OF H.M.S. CHALLENGER. 
Orhulitia umversa, together with other Foraminifera and fragments of Echinoderms. 
The mineral partieles appeared to make np 1 per cent, of the deposit, and consisted of 
hornblende, magnetite, felspar, vitreous fragments, and a few quartz grains. There was 
from 2 to 1 0 per cent, of Diatoms and Radiolaria in these Globigerina Oozes. 
The remaining variety of deposit (Red Clay) was obtained in lat. 42“ S. at a depth of 
2600 fathoms (see Chart 24). It contained 18 per cent, of carbonate of lime, consisting 
of entire shells and fragments of Glohigerina hulloides, Globigerina inflata, and Glohi- 
gcrina mbra, PulvinuUna micheliniana, Orhulina universa, a few other Foraminifera, 
Coecoliths, Polyzoa, and fragments of Echinoderms. The mineral particles only formed 
1 per cent, of the deposit, and consisted of felspars, hornblende, augite, magnetite, 
pumice, fragments of volcanic glass, and grains of peroxide of manganese, with a mean 
diameter of about 0'08 mm., while a few rounded fragments of quartz reached a diameter 
of 0’5 mm. The remainder of the deposit consisted essentially of amorphous and clayey 
matter with very minute fragments of minerals and pumice. There was a larger per- 
centage of carbonate of lime in the upper layers of the deposit than in the deeper ones. 
The trawl brought up 10 or 12 litres of manganese nodules, pumice stones, rolled pebbles 
of gneiss, fragments of palagonite, earbones of Cetaceans, and sharks’ teeth. 
From the foregoing description it appears that the deposits forming at the most 
southerly points reached by the Challenger are composed chiefly of continental debris 
earned into the ocean by the floating ice of these regions, and that this material makes 
up le.ss and less of the deposit as the distance from the Antarctic Continent increases until 
it almost disappears about lat. 46° or 47“ S., although at other longitudes in the 
Atlantic and Pacific continental debris from the Antarctic Continent appears to be carried 
fully ten degrees farther to the north. The deposits along the Antarctic Ice-barrier, 
which have been called Blue Muds, resemble in many respects the deposits formed at 
similar depths off the Atlantic coast of British North America. The nature of the rock 
fragments dredged in these latitudes conclusively proves the existence of continental 
land certainly of considerable extent within the Antarctic Circle. One of the fragments 
of gneiss dredged from a depth of 1950 fathoms measured 50 by 40 centimetres, and 
weighed more than 20 kilogrammes. In the region occupied by the Diatom Ooze, 
northward of the Blue hluds, the predominant feature of the deposit is due to the 
innumerable frustulcs of Diatoms and skeletons of Radiolaria which have fallen from the 
surface and .subsarflice waters of the ocean. Farther north again the pelagic Foraminifera 
{)rcdominate in the deposit, except at the depth of 2600 fathoms, where the greater part 
of them has been removed by the solvent powers of the sea-water, as is usual at the great 
dcptks of the ocean. 
South of lat. 50° S., Diatoms were frequently met with in the surface nets in 
enormous abundance. The most abundant were various species of Chxtoceros, 
but there were also many other genera. The tow-nets were on some occasions 
