22 THE DEPTH AND MARINE DEPOSITS OF THE PACIFIC OCEAN. 
A very interesting fact brought to light by the cruises of the “ Albatross ” 
and the “Nero” is that the presence of manganese nodules in a deposit is 
not at all incompatible with a high percentage of calcium carbonate, and 
especially if many volcanic minerals are at the same time present in the 
deposit, as indeed was indicated in the description of Station 297 in the 
Challenger Report on Deep-Sea Deposits. Nodules were found in one deposit 
containing 33 per cent of calcium carbonate, and in eight typical Globigerina 
Oozes containing respectively 77, 62, 78, 54, 60, 75, 50, and 65 per cent of 
calcium carbonate. We have here a large proportion of the total number 
of stations where nodules were dredged, so that we may infer that 
manganese nodules are by no means exclusively characteristic of Red Clay. 
Their origin depends more on a ready supply of manganese and iron than 
on depth, and is not dependent on the presence or absence of calcareous 
organisms.’ 
The nodules, and specially those that are in course of formation, are often 
associated with palagonitic tuffs, on which the oxides form a coating of 
variable thickness; the oxides also form irregularly distributed nuclei within 
the cakes of palagonitic tuffs. We may mention here the peculiar forma- 
tion of Station 4693 (lat. 26° 30'S, long. 105° 45’ W.), where the oxides 
are deposited within, and on the surface of, consolidated cakes of Globigerina 
Ooze. This is the only instance met with during the cruise of a deposit being 
dredged as consolidated lumps. During the cruise of the “Challenger” a 
large piece of consolidated Globigerina rock was dredged between Arrou and 
Banda at a depth of 129 fathoms; this rock differs from the hardened ooze 
described here in being quite hard, requiring a sharp blow of the hammer to 
break it, and, moreover, it is not associated with manganese oxide. The 
formation most nearly resembling this one appears to be a Globigerina Ooze 
dredged by the S. 8. “ Britannia” in the year 1901 in lat. 14° 32’ S. and 
long. 175° 55’ W. According to the report by Sir John Murray and Mr. 
Peake, the material came up perfectly hard and dry, and required a hammer 
to knock it out of the tubes. Nevertheless, the phenomenon is of rare 
occurrence, and is worth mentioning. 
Philipsite is by no means rare in the Globigerina Ooze of this part of the 
Pacific Ocean. It was met with in five typical samples containing respec- 
1 Reference to ‘‘ A Contribution to the Oceanography of the Pacific,” by James M. Flint (Bull. 
U.S. Nat. Mus., No. 55, 1905), will show that, in that part of the ocean traversed by the “ Nero,” man- 
ganese concretions are generally present, and sometimes quite numerous, in Globigerina Ooze. 
