THE DEPTH AND MARINE DEPOSITS OF THE PACIFIC OCEAN. 155 
north to 2° south latitude, the southern boundary coinciding with the 
parallel of 2° south. A third considerable area of Globigerina Ooze sur- 
rounds the Caroline archipelago, and a fourth surrounds the Marshall and 
Gilbert archipelagos, while several small isolated areas surround the scat- 
tered groups of islands, and cover the summits and flanks of some sub- 
marine elevations. It will be observed that generally the Globigerina Ooze 
is found in depths between 1000 and 2300 fathoms, while the Red Clay is 
found in depths exceeding 2300 fathoms. There are, however, important 
exceptions to this statement. 
Ill. Diatom Ooze.—This type occurs in the form of two broad bands, 
the larger in the far south and the smaller in the far north. The south- 
ern one forms part of the circumpolar band surrounding the Antarctic 
continent, outside the band of Blue Mud, and covers an area of about two 
and a half millions of square miles, while the northern one stretches 
across the northern boundary of the Pacific, from Japan on the west to 
Vancouver on the east, and covers over a million square miles. One of 
the most interesting results of the recent expedition of the “Albatross” 
is the discovery of this type of deep-sea deposit, so characteristic of high 
latitudes, within the tropics, viz., in latitude 12° south, off the west coast 
of South America, where, however, it has apparently a very restricted 
area of distribution. 
IV. adiolarian Ooze. — This type covers two large and two or three 
small areas in the tropical part of the Pacific. The most important one 
is the comparatively narrow band in latitude 10° north, stretching from 
165° to 80° west longitude, and covering an area of nearly two million 
square miles. A second area, nearly a million square miles in extent, 
stretches from latitude 8° north to 12° south, and from longitude 180° to 
164° west. Of the other smaller areas, one occupies the Challenger Deep 
in the North Pacific, extending from 143° to 147° east longitude and 
from 12° to 15° north latitude, and two lie in the South Pacific, one in 
latitude 3° to 8° south and longitude 151° to 153° west, the other in lati- 
tude 10° south and longitude 156° west. 
V. Pleropod Ooze. —It is rather curious to note the absence of this type 
in the northern and eastern Pacific, the most northerly and easterly posi- 
tion hitherto known being latitude 9° south and longitude 139° west in the 
Marquesas group. Several small areas of Pteropod Ooze are dotted over the 
western portion of the Globigerina Ooze area of the South Pacific, especially 
