DEEP-SEA EXPLORATION. 
399 
The term “fine washings” is nsed to indicate the amorphous clayey matter in a deposit left after 
treatment with dilute hydrochloric acid. 
2. liadiolarian ooze. — This deposit resembles the red clay in most respects, but contains a much 
larger number of radiolariau shells, skeletons, and spicules, together with 8i)ougo spicules and 
I'rustules of diatoms. The Challenger samples ranged in depth from 2,350 to 4,475 fathoms, the 
average being 2,894 fathoms. There is usually only a trace of carbonate of lime, though it may rise 
to nearly 20 per cent, principally due to the remains of pelagic foraminifera, along with a few other 
calcareous fragments. Manganese nodules, palagonitio fragments, sharks’ teeth, earbones of cetaceans, 
zeolitio crystals, and cosmic spherules have been found in nearly all the samples of radiolarian ooze. 
Average composilion of the Challenger samples of radiolarian ooze. 
Carbonate of lime: 
Pelagic foraminifera 3.11 
Bottom -living foraminifera 11 
Other organisms 79 
4.01 
Residue : 
Siliceous organtsms 54.44 
Minerals 1.07 
Pine washings 39.88 
9.5. 99 
100 
3. Diatom ooze. — This deposit when wet has a yellowish straw or cream color. When dried it is 
nearly pure white, resembling flour. Near laud it may assume a bluish tinge. The surface layers 
are thin and watery, but the dee^ier ones are more dense and coherent, breaking uji into laminated 
fragments. It is soft and light to the touch when dried, taking the impress of the fingers and sticking 
to them like flue flour. Small samples a]ipear quite homogeneous and uniform, but in all the Challenger 
soundings there were fragments of minerals and rocks, and gritty particles can generally be felt when 
the substance is xiassed between the fingers. The C/ml/cwycr samples varied in de]ith from 600 to 1,975 
fathoms, the average depth being 1,477 fathoms The principal part of the deposit is made up of the 
dead frustules of diatoms, together with radiolarian remains, sponge spicules, and their fragments. 
The carbonate of lime varies from 2 to over 30 per cent, due principally to the dead shells of pelagic 
foraminifera. The mineral particles vary greatly in nature, size, and abundance, sometimes volcanic 
rocks and minerals, sometimes those of ancient and sedimentary formations iiredominatiiig. This was 
to be expected, for all the Challenger samples lie within the region of floating ice in the southern 
hemisphere. 
Average composition of the Challenger samples of diatom ooze. 
Carbonate of lime : 
Pelagic foraminifera 18. 21 
Bottom-living foraminifera 1. 00 
Other organisms 3. 15 
22.90 
Residue: 
Siliceous organisms 41. 00 
Minerals 15.00 
Pine washings 20. 44 
77.04 
100 
4. Ctlohigerina ooze. — This deposit is white, milky yellow, rose, brown, or grayish, depending on 
the nature of the inorganic substances mixed with the foraminifera shells. The iirevailing color is 
milky white or rose-color far from land, and dirty white, blue, or gray near land, when there 
is a considerable quantity of detrital matter from rivers in the deposit. It is line-grained and 
homogeneous. In tropical regions many of the foraminifera are visible to the naked eye, while in 
temperate regions the form of the organisms is, as a rule, indistinguishable without tlie aid of a lens. 
When dried a globigerina ooze is usually pulverulent, but some specimens with a low percentage of 
carbonate of lime cohere slightly. The Challenger samides ranged in depth from 400 to 2,925 fathoms, 
the average depth being 2,002 fathom.s. In addition to the pelagic foraminifera many other organisms 
contribute to the carbonate of lime in a globigerina ooze, some living in the surface waters, others at 
the bottom of the sea. Among the former are pelagic mollusks (pteropods and heteropods) and jielagic 
calcareous algte (coccospheres and rhabdos^iheres with their broken jiarts, coccoliths and rhabdoliths); 
and among the latter are remains of mollusca, echinoderms, annelids, corals, polyzoa, and bottom- 
living foraminifera. The percentage of carbonate of lime varies from 30 to nearly 100 per cent, the 
estimated percentage due to the presence of the dead shells of pelagic foraminifera alone being usually 
