174 
THE VOYAGE OF H.M.S. CHALLENGER. 
siliceous organisms made up 5 to 10 per cent. Two or three rounded nodules of pumice, 
1 to 3 centimetres in diameter, were obtained from 1050 fathoms. 
Mecuigis Island to Admi)'alty Islands. — In this section (see Chart 31 and Diagram 
1 5) the deposits presented some points of considerable interest. At 500 fathoms, near 
]\leangis Island, the deposit was a Blue ]\Iud with 34 per cent, of carbonate of lime, made 
up principally of pelagic Foraminifera, and over 20 per cent, of mineral particles, includ- 
ing felspars, quartz, augite, hornblende, magnetite, and pumice. In the trawl were many 
fragments of trachytic tufa. The deposit from 2550 fathoms was a Red Clay containing 
no carbonate of lime, and comparatively few mineral particles, which were volcanic, the 
great ma.ss of the material being made up of fine amorphous and clayey matter. The 
trawl brought up from this depth several fragments of pumice about the size of a hen’s 
egg; these all contain porphyritic minerals, and are in some cases slightly impreg- 
nated with manganese. At 1675 and 2000 fathoms were found Globigerina Oozes 
with 49 and 35 per cent, of carbonate of lime respectively. Mineral particles were 
few and small, and consisted of felspars, pumice, augite, and magnetite. Fewer Cocco- 
liths and Rhabdoliths were present in the greater depth. The trawl brought up from 2000 
fathoms a considerable number of pumice stones varying in size from that of a marble to 
that of a hen’s egg. The surfaces of most of these were impregnated with manganese. 
At 2000 fathoms nearer the coast of New Guinea the deposit was a Blue Mud containing 
13 per cent, of carbonate of lime, chiefly derived from remains of surface Foraminifera. 
The mineral particles were exceedingly few and small, and consisted of fragments of fel- 
spar, augite, volcanic glass, and quartz. Two or three small pellets of pumice and several 
worm tubes were obtained in the sounding tube. The deposit in 1070 fathoms, between 
New Guinea and the Admiralty Islands, was a Blue Mud with a reddish surface layer, and 
contained 17 per cent, of carbonate of lime. No difference could be detected in composi- 
tion between the two layers. Mineral particles made up 10 per cent., but the mass of 
the deposit wa-s fine amorphous clayey material. The trawl brought up a large quantity 
of mud, large pieces of pumice, fragments of wood and fruits, Pteropod and lanthina 
shells, and nearly two hundred specimens of deep-sea animals ; the net was covered with 
a branching Rhizo})od. The pieces of pumice varied in size from that of a pea to that of 
a hen’s egg, and were slightly impregnated with manganese, and overgrown by Serjmla 
and Jhjperammina vayans. Siliceous organisms made up 4 per cent. 
Jlurnholdt Jkty,New Guinea. — The deposit in 37 fathoms was a Blue Mud containing 
29 per cent, of carbonate of lime, derived from pelagic and other Molluscs, bottom-living 
and pelagic Foraminifera, Ostracodcs, fragments of Echinoderms, and calcareous Algm. 
The mineral ]»artifles with a mean diameter over 0'05 mm. are estimated to make up 20 
|)cr cent., while the fine washings largely consist of smaller mineral particles. A ""few 
green en.sts of Foraminifera remained after treatment with dilute acid. 
(yY Ad tnirahy Islands . — From 16 to 25 fathoms in Narcs Harbour (see Chart 34) 
