6 "ALBATROSS" EASTERN TROPICAL PACIFIC EXPEDITION. 



latitude of Valparaiso ; but nothing is known of the character of the bottom 

 on the area interveninsr between the lines of the ''Albatross" and " Chal- 

 lenger." The western and northern and eastern limits of the Radiolarian 

 ooze (PL 3) indicate a great tract partly covering the area of manganese 

 nodules. 



To the west of the Radiolarian ooze area lies a great tract of Globigerina 

 ooze ; it is east of the Marquesas and of the Paumotus and extends north 

 some way into Moser Basin (PI. 3). 



Diatoms are found in a very wide belt reaching from the equator to 

 nearly the general latitude of 15° S., in some localities south and west of 

 Aguja Point, as well as others. Close to the South American coast they 

 occur in sufficient quantities to have formed silicious earth. 



It will be noted that the belt where diatoms occur is entirely within 

 the influence of the western and northern set of the Humboldt current, 

 and that while diatoms are found in great abundance in an area near the 

 equator, yet they have undoubtedly been brought north by the Humboldt 

 current from more southern latitudes than those explored by the " Alba- 

 tross," and have been spread westward by the prevailing southeast trades 

 of the belt where they are found (PL 4). 



BOTTOM FAUNA OF THE EASTERN TROPICAL PACIFIC. 



Plate 3*^. 



Hauls of the trawl made off the Galapagos and at the western extremity 

 of our lines off Aguja Point brought us within the area of the manganese 

 nodules, with its Radiolarian ooze mud, Cetacean earbones, and beaks of 

 Cephalopods ; nothing could stand the damaging work of these nodules in 

 grinding to pieces all the animal life the trawl may have obtained (PL 3). 

 Down to a depth of 2200 fathoms or so the bottom was constituted of 

 Globigerina ooze, its character being more or less hidden when near the 

 coast by the amount of detrital matter and terrigenous deposits which 

 have drifted out to sea. 



North of the Galapagos, as in the 1891 expedition,' we found vegetable 

 matter at nearly all the stations, and between the Galapagos and Callao 

 such material was not uncommon in the trawl. 



Beyond the line of 2200 fathoms dead radiolarians become quite abun- 



» Bull. M. C. Z. XXIII, No. 1, p. 11, 1892. 



