THE VOYAGE OF II.M.S. CHALLENGER. 
3(U 
these nuclei is very remarkable, especially when the small proportion of siliceous organisms 
in the deposit is remembered. One of the tow-nets contained several rounded lumps of 
the dei>osit, loosely held together by dendritic depositions of manganese and iron, which 
seemed to indicate the beffinnins: of the nodule formation. 
Station 299, 2160 fathoms. — The deposit at this station was a Blue Mud, but just on 
the border-line between Blue I\Iud and Bed Clay. There was over a litre of manganese 
nodules in the trawl. Some of these were formed round nuclei of pumice, while in others 
no apparent nucleus was present. The in’evailing form, represented in PI. III. fig. 4, 
is like an inverted eone with the apex removed. The lower part of the nodule was 
very areolar in structure, containing much clayey matter in alternate layers, and con- 
centric round a point which would be represented by the apex 
of the cone. The upper part of the cone is also made up of 
concentric layers, but is much harder and more compact. 
Another nodule from this station is represented in Fig. 3.5, 
with a Scalpellum attached. There were also in the trawl a 
tymj)anic bulla of a Glohiocephalus, with the petrous bone 
attached, and a Cephalopod beak, both coated with manganese. 
Station 300, 1375 fathoms. — The trawl appeared to have 
caught on the bottom, and it was with great difficulty that it 
could be released, the accumulators being stretched to their 
utmost. The beam of the trawl was scored in several places by 
patches of black manganese, as if the beam had caught on 
something coated with that substance. Amongst the ooze in 
the bag of the trawl were three or four basaltic pebbles, coated 
with manganese, and four flattened pieces of volcanic tufa, 
coated on one surface by deposits of manganese, G to 12 mm. 
in thickne.ss. 
Station 302, 14.50 fathoms. — The trawl, as at Station 300, 
caught upon the bottom, and was with difficulty released. The 
bag of the trawl contained about a peck of ooze, containing 
many manganese concretions and volcanic pebbles. Among 
manganese nodules were some large flat-shaped fragments, 
statmn 290 , 2100 fathoms. .South ;ij)pareiitly toi’ii from larger masses. They consisted of alter- 
nate layers, and were black-brown throughout. The majority 
of tlic nodulcH Inul nuclei of basic volcanic glass, surrounded by altered layers ; one of the 
nuclei is rej»resentcd in PI. XVI. fig. 4, and another in PI. XVI 1. fig. 4. Other nodules 
aj)jicared to have been formed around small aggregations of the deposit, for in them could 
be .seen many easts of Foraminif(*ra. 
