THE DEPTH AND MARINE DEPOSITS OF THE PACIFIC OCEAN. 19 
found at such a depth. At the next station in 2391 fathoms (lat. 18° 29’ S., 
long. 130° 51’ W.), the deposit was Red Clay containing 18 per cent of 
calcium carbonate; thence northwards the deposit continued to be Globi- 
gerina Ooze with a percentage of calcium carbonate exceeding 60 as far as 
lat. 5° S., then, finally, a peculiar Red Clay was met with at 1955 fathoms 
(lat. 10° 38’ N., long. 106° 48’ W.), containing no calcium carbonate. 
Typses oF Deposits. 
The deposits obtained during this cruise of the U.S. S. “ Albatross” all 
belong to “Deep-sea Deposits” found beyond the 100-fathoms line. The 
ordinary classification still holds good in this case, and the material at hand 
gives typical examples of both terrigenous and pelagic deposits. As may be 
expected from the configuration of the eastern shores of the Pacific, the ter- 
rigenous deposits form only a narrow belt along the continental shelf of 
North and South America. We have there Blue Muds, Green Muds, and 
Green Sands, giving place to pelagic deposits as the depth increases towards 
the open sea. 
Pelagic Deposits. Gtobigerina Ooze was the deposit most frequently met 
with, 36 samples having been studied. As regards the organisms that make 
up the calcium carbonate, it was at first proposed to give a complete list 
of the various species of Foraminifera, but as no difference could be found 
between the organisms of the successive stations, the Foraminifera are 
indicated merely as pelagic or bottom-living. The pelagic Foraminifera 
usually present are: Globigerina bulloides, Globigerina conglobata, Globigerina 
aquilateralis, Globigerina rubra, Globigerina dubia, Globigerina sacculifera, Orbu- 
lina universa, Spheeroidina dehiscens, Pullema obliquiloculata (very frequent), 
Pulvinulina menardii, and Puleinulina tumida. Fishes’ teeth and Echinoid 
spines are the most frequent calcareous remains that accompany the 
Foraminifera. 
Red Clay. The collection contains sixteen samples of Red Clay. The 
deepest sounding where this deposit was found was at 3120 fathoms, and 
the shallowest 1955 fathoms, the average depth being 2404 fathoms. The 
1 The determination of the percentage of calcium carbonate was done throughout by means of 
the method based on the displacement of carbonic acid by an acid and loss of weight, a modification 
of Mohr’s apparatus being used. This method is quite accurate and sensitive enough for the purpose, 
especially as calcium carbonate cannot be equally distributed throughout a sample, even when small, 
as is naturally the case with a deposit that has not been chemically, but mechanically, laid down, the 
size and abundance of the constituents varying continually, as may be expected from their organic 
origin. 
