OCEANOGRAPHY OF THE PACIFIC. 11 



entirel}^ in the fine washings, while in others they may be compara- 

 tively coarse. Volcanic glass is sometimes present in notable quantity. 

 Manganese-iron nodules, and concretions upon other minerals, are 

 almost universally present. They are the black specks ("bk. sp.") so 

 frequently recorded on the official records, the larger ones being gener- 

 ally referred to as rock C"' R.'') Phillipsite is a freqent constituent. 

 It is found as quite perfect crystals, single, twinned, or multiple, or 

 more frequently as spherules made up of crystals arranged radially. The 

 simpler forms are found in great numbers at station 331 (2,997 fathoms), 

 and the spherules at station 495 (3,204 fathoms). Vertebrate remains, 

 teeth of sharks and other fishes, and otoliths, have not been observed 

 in this or other deposits, though carefull}- looked for. 



This red clay deposit is indicated in 75 per cent of the soundings 

 from which specimens were received (1,043 out of 1,394), between the 

 Hawaiian Islands and the Philippines. It is conspicuously absent 

 except at three stations along the line from Guam to Yokohama, being 

 replaced at corresponding depths b}^ volcanic mud. It is probal)le 

 that this belt of volcanic mud does not extend far from the range of 

 volcanic islands along which the cable route passes. 



The least depth at which a distinctly red cla}^ deposit has been noted 

 is at station 680 — 2,010 fathoms. It is always found in abysmal depths. 

 Ordinarily, as the contour line rises above the 2,500-fathommark foram- 

 inifera rapidly increase in numbers and perfection of form, and soon 

 justify the classification of the deposit under the head of globigerina ooze. 



Glohigerina ooze. — Globigerina ooze is defined as a deposit containing 

 over 30 per cent of calcium carbonate, principally in the form of 

 minute shells of foraminifera. Other organic remains commonly 

 found in this deposit are sponge spicules, radiolaria, diatoms, and the 

 ver}^ minute coccoliths and rhabdoliths. As a rule, in this part of the 

 Pacific Ocean globigerina ooze will be found wherever the depth is 

 less than 2,200 fathoms. The exceptions are found in the region of 

 volcanic islands or submarine volcanic peaks where the foraminifera 

 seem to be overwhelmed by volcanic sand, and in the vicinity of island 

 shores where coral sand or blue or green mud may predominate. The 

 globigerina ooze, wherever found on the line of this survey, is composed 

 principally of the few species (about 20) of foraminifera known to be 

 pelagic. Bottom living species are rare and individuallj'^ few in num- 

 ber. The proportion of mineral matter, other than calcium carbonate, 

 in this deposit is relatively small. Manganese concretions are gener- 

 ally present and sometimes quite numerous, and fragments of pumice 

 are common. Crystals and spherules of phillipsite a,re often noted. 

 The finer mineral fragments are quite lost in the mass of foraminifera, 

 but appear when the latter are dissolved out with acid. At one sta- 

 tion — 643, 1,757 fathoms — the cavities of very many of the shells were 

 found to be filled with a siliceous deposit forming complete casts of the 



