THE DEPTH AND MARINE DEPOSITS OF THE PACIFIC OCEAN. 13 
of Letté while crossing the volcanic ridge which runs parallel to the Tonga 
Island plateau. Crossing the eastern Fiji plateau we meet with deposits of 
coarse coral sand, pteropod ooze, and fine coral ooze, associated with man- 
ganese particles and Globigerinz, much as in the deposits of the Paumotus. 
“On our way through the Ellice and Gilbert Islands to Jaluit we obtained 
in the proximity of the islands coarse coral sand, pteropod ooze, and fine coral- 
sand ooze more or less mixed with Globigerinz. In the deeper waters sepa- 
rating the islands of each group, and the groups themselves, we encountered 
only Globigerina ooze, varying greatly in the size of the species obtained ; 
very coarse species being met with . . . in the Gilbert group in 1365 and 
1569 fathoms. .. . 
“Tn 2221 fathoms, between Apamama and Maiana, we met with the same 
Globigerinx, characterizing the equatorial current, which we had obtained 
before in the Paumotus and to the northward. Although on our way to 
Jaluit from Taritari we sounded in over 2500 fathoms, yet we nowhere 
obtained red clay in the bottom deposit, either on that line or in the deep 
water separating the islands of the Ellice or of the Gilbert group. . . . We 
found the same conditions in the Marshall group, coarse coral-sand, passing, 
according to depth and distance from land, into fine coral-sand, or coral-sand 
ooze, with a gradually increasing percentage of Globigerinw. These are 
met with in as great a depth as 2613 fathoms, between Jaluit and Ailanglab 
Lab and all through the Marshall group in deep water in the channels between 
the different groups. . . . 
“Red clay is, however, met with in the bottom deposits of the northern 
part of the Marshall group between Rongelab and Likieb . . . in depths 
varying from 2469 to 2609 fathoms, though even at that depth it is asso- 
ciated with a considerable percentage of Globigerine. 
“Similarly on our way through the Carolines we found Globigerins to 
constitute a considerable percentage of the bottom deposits to depths of 
nearly 2500 fathoms. . . . The bottom deposits in the Carolines consist, as 
we would naturally expect from the geological structure of the Carolines, 
near the island groups, in great part of volcanic mud mixed with coral sand 
and Globigerine ; the size of the sand, volcanic or coral, gradually decreasing 
as the depth increases. . . 
“Tt is only as we pass into the ‘Caroline Deep’ separating the Carolines 
from Guam and the Ladrones that we come upon bottom deposits consisting 
of red clay, manganese nodules, and pumice, as well as volcanic particles: 
