REPORT ON THE DEEP-SEA DEPOSITS. 
203 
basin. The Red Clay of the Atlantic is usually of a reddish colour, the dark chocolate- 
coloured variety, with its zeolitic crystals formed in situ, found in the Pacific and also in 
the Indian Ocean, not having been met with in the Atlantic. 
In the Indian Ocean, again, the area covered by Red Clay is less than that covered 
by Globigerina Ooze, being estimated at 4,900,000 square miles. It is found to extend 
from off the western shores of Australia and the East Indian Islands, south of the equator, 
across the ocean towards Madagascar, reaching also to a small extent into the Southern 
Ocean to the south and west of Australia. In the North Indian Ocean there is a small 
detached patch in the deep water of the Arabian Sea, between the Maidive and Laccadive 
Archipelagoes and the coast of Africa. 
In the Pacific the Red Clay attains its most typical and most extensive development, 
covering by far the greater portion of the sea-bottom. Its area is estimated at about 
40,800,000 square miles. The whole of the deep water of the eastern portion of the 
Pacific basin is occupied by Red Clay, and it extends more or less uninterruptedly over 
the western portion, approaching the shores of Japan in the north and of New Zealand in 
the south. It covers also a considerable tract in the Southern Ocean, where there is a 
detached area situated some distance off the coast of Chili. There are several detached 
patches occupying the deeper water between the various groups of islands of Oceania, 
viz., two small areas in the Coral Sea between the New Hebrides and the north-east coast 
of Australia ; another between New Caledonia and New Zealand ; another between the 
Solomon Islands and the Marshall and Gilbert groups ; another between the north coast 
of New Guinea and the Caroline group, a considerable area in the deep water between 
the Philippines, Japan, Bonin Islands, Ladrone Islands, and Pelew Islands ; a consider- 
able area is also found between Australia and New Zealand, extending into the Southern 
Ocean. 
Radiolarian Ooze. 
This deposit, like the Red Clay, is confined to the greater depths of the ocean, 
indeed, as will be presently pointed out, it has a greater average depth than the Red 
Clay. The name was adopted during the cruise of the Challenger by Mr. Murray for 
those deposits which, while resembling Red Clays in most respects, differ from them 
in containing a much larger number of Radiolarian shells, skeletons, and spicules, together 
with Sponge spicules and the frustules of Diatoms. There is in short little, if any, 
difference between these deposits and Red Clay, except what may be attributed to the 
greater or less abundance of these remains of siliceous organisms. The colour is red, 
chocolate, or occasionally straw coloured ; it is less plastic than the Red Clay, at least 
the typical examples are so. The peroxides of iron and manganese are everywhere 
present, as are also fragments of pumice, augite, felspars, hornblende, magnetite, pala- 
gonite, chondritic and other cosmic spherules. Manganese nodules and palagonitic 
