on board H.M.S. 'Challenger. 3 507 



gauese T ^ inch in thickness; very many Diatom, Eadiolarian, 

 and Challengeria remains ; very many manganese grains. 

 The trawl brought up many manganese nodules or concretions and 

 two shark's teeth ; these nodules had in most cases a nucleus of pumice. 



Sounding 267. 2nd July, 1875. 205 fathoms. Lat. 36° 10' N., 

 long. 178° 0' E. A grey clay containing : — Much amorphous clayey 

 matter ; many fine white mineral particles ; many Eadiolarian and 

 Diatom remains ; a few pelagic Foraminifera and their broken parts 

 and Coccoliths. 

 Several pumicestones came up in the trawl, the smaller ones having a 

 coating of manganese. 



Sounding 268. 3rd July, 1875. 2530 fathoms. Lat. 35° 49' K, long. 

 179° 57' W. (a) Eed clay, the upper layer in the tube 1 inch thick, 

 containing : — Much amorphous clayey matter ; many fine mineral 

 particles ; many Eadiolarian and Diatom remains ; some manganese 

 grains ; no carbonate-of-lime organisms. 



(b) A grey clay, in lower part of the tube 4 inches thick, con- 

 taining : — Same as in the upper layer, but, in addition, a good 

 many pelagic Foraminifera and Coccoliths, and fewer manganese 

 grains. 

 Sounding 269. 5th July, 1875. 2900 fathoms. Lat. 37° 41' IS"., long. 

 177° 4' W. A red clay containing : — Much amorphous clayey matter; 

 many fine mineral particles, pieces of pumice, and black and white 

 crystals; many Eadiolarian, Diatom, and Challengeria remains; two 

 broken pieces of Globigerina were noticed. 

 The trawl brought up many manganese nodules, pieces of pumice and 

 sharks' teeth ; a few of these had a coating of peroxide of manganese 

 | inch in thickness. Many of the nodules had a nucleus of pumice sur- 

 rounded by J an inch of the black manganese ; some were black man- 

 ganese throughout excepting a small spot in the centre ; one had a sili- 

 ceous sponge (Farrea) imbedded in an inch of the black manganese. 



fathoms. , o / 



Sounding 270. 7th July, 1875. 3000. Lat. 37 59 K, long. 171 68 W. 

 „ 271. 9th „ „ 3050. „ 37 49 R, „ 166 47 W. 

 „ 272. 10th „ „ 2900. „37 37N., „ 163 26 W. 

 „ 273. 12th „ „ 2740. „ 37 52 INT., „ 160 17 W. 

 In each case a red clay containing : — Much amorphous clayey 

 matter; very many fine white mineral particles (pumice) ; very many 

 Eadiolarian, Diatom, and Challengeria remains ; a good many man- 

 ganese grains. In 270 and 271 the remains of siliceous organisms 

 make up over one third of the bottom in bulk. 

 On the 12th July the trawl brought up fully a bushel of manganese 

 nodules ; these were chiefly of a rounded or kidney-shape, like a lot of 

 potatoes, the largest being about the size of a cricket-ball : one of the 



