EEPOKT ON THE DEEP-SEA DEPOSITS. 
175 
the bottom consisted of Cora] Sands and Muds yielding on analysis about 87 per cent, of 
carbonate of lime, coming from fragments of Coral, calcareous Algse, Lamellibranchs, 
Gasteropods, pelagic and bottom-living Foraminifera. Many of the large fragments were 
overgrown with Serpula and Polyzoa. Mineral particles were few and small, and con- 
sisted of pumice, felspar, volcanic glass, augite, magnetite, quartz, and some manganese 
grains. A few imperfect casts of the organisms remained after treatment with dilute 
acid. From 150 fathoms, about a mile from the reef, traces of a greenish coloured Volcanic 
Sand were obtained. 
Admiralty Islands to Japan . — The deposits between the Admiralty Islands and 
Japan (see Chart 31) were of very high interest, chiefly from the large number of Radio- 
laria present in them, and also from the almost complete absence of carbonate of lime in 
the deeper soundiugs. In depths greater than 2400 fathoms there was either no 
carbonate of lime in the deposit or only a small percentage, as for instance in 2450 
fathoms in lat. 2° N., where there was 6 per cent., due to the presence in the deposit of 
a few broken fragments of pelagic Foraminifera shells. On the other hand, there was 
79 per cent, of carbonate of lime in the deposit at 1850 fathoms on the Caroline Islands 
plateau, which was a Globigerina Ooze made up principally of the shells of pelagic 
Foraminifera, Coccoliths, and Rhabdoliths. The absence of the shells of Pteropods, 
Heteropods, and other pelagic Molluscs from this deposit is worthy of note, as well as the 
absence of the Foraminifera shells from all the deeper deposits, as these organisms were 
very numerous at the surface throughout the whole region. As already stated, siliceous 
shells and skeletons were especially abundant in some of the deposits in this section, 
more numerous than in any deposits previously met with during the cruise. In one 
instance these beautiful little organisms made up about four-fifths of the deposit, which 
was in consequence called a Radiolarian Ooze. This was the case in the deepest 
sounding, viz., 4475 fathoms, the greatest depth from which a specimen of the bottom 
had hitherto been obtained. On this occasion the sounding tube had sunk about 3 or 4 
inches (8 or 10 centimetres) into the bottom and brought up a section to that extent. 
The layer, which formed the upper surface at the bottom of the sea, was of a reddish or 
chocolate colour, and contained, besides the Radiolarian and Diatomaceous remains, 
numerous small round pellets of manganese peroxide, fragments of pumice, and clayey 
matter. The deeper layers were of a pale straw colour, and resembled both in appearance 
and touch the Diatom Ooze from the Antarctic Ocean. These deeper layers had a 
laminated structure, and were very compact and difficult to break up, being composed of 
felted masses of Radiolaria and frustules of Diatoms. 
Pumice was very abundant in all the deposits, the trawl frequently bringing up 
numerous rounded pieces, many of them partly decomposed and coated with manganese 
peroxide. The mineral fragments in the deposits appeared to be chiefly derived from 
the pumice, except in the soundings close to the Japan coast. All the deeper deposits 
