on board H.M.S. 'Challenger. 3 517 



with streaks of black, as if they had been dragged over lumps of manga- 

 nese. 



" The tow-net just behind these weights had in it very many Globigerince, 

 Pulvinulinw, and one or two Orbidinw (all dead), a good many manganese 

 pellets and a very little mud. 



" This net would seem to have caught the particles knocked up by the 

 weights in front. One of the tow-nets at the trawl was full to the brim 

 of a yellow or, rather, light-brown-coloured mud, in which were many 

 manganese nodules. Being so full of mud, not much of the finer portions 

 of the bottom could have been washed away ; hence this tow-net of mud 

 gives us information from which some idea may be formed of the ratio 

 which the manganese nodules bear to the ooze. In a peck of the mud 

 there was a little over a quart of manganese nodules. The nodules were 

 all nearly round. Some of the smaller ones were composed of the black 

 manganese to the centre, while some had just a small yellow spot in the 

 centre. Some of the larger ones had a yellow or dark green nucleus of 

 about half an inch in diameter, which was surrounded by concentric layers 

 of peroxide of manganese of half an inch in thickness. The yellow or 

 green nucleus was soft, and could be cut with the knife like new cheese. 

 Under the microscope it presented a mottled appearance, with yellow and 

 light- and dark-green spaces, many of these being partially surrounded 

 with agate bands. 



" Forarninifera could also be seen imbedded in the mass ; but all the car- 

 bonate of lime had been removed, strong nitric acid having no effect on 

 any part of this nucleus. Birds'-feet-like extensions of the black manga- 

 nese ramified into the yellow nucleus ; and it seemed as if the manganese 

 was extending into the nucleus as well as being deposited in concentric 

 layers around it, as in those instances where pumice forms the nucleus of 

 a nodule. There were lumps of the bottom in the tow-net which seemed 

 to show the beginning of this process of nodule-formation. These lumps, 

 which were of a redder colour than the rest of the bottom, seemed to be 

 cemented by a red substance (?). 



" Examined a portion of the bottom in the same way as usual with the 

 soundings. It contained : — many Grlobigerinas, Pulvinulinas (the pyra- 

 midal variety), and a few Orbulinas ; one or twoUvigerinas, and some Bilo- 

 culinas and others ; two arenaceous forms of Foraminifera, the tests com- 

 posed of particles of manganese and a red mineral ; many Coccoliths and 

 Ehabdoliths ; only two portions of siliceous spines and three Eadiolaria 

 were observed. 



" Eemoving the manganese from the washing there remained : — A good 

 many mineral particles (these were almost all of a dark lead-colour and 

 very areolar structure, reminding one of volcanic ash and scoria) ; one 

 small yellow crystal, several pieces of a red cherty-like mineral, and one 

 quartz-like particle were noticed ; manganese grains were abundant." 

 Sounding 319. 17th November, 1875. 2225 fathoms. Lat. 34° 7' S., 



