THE DEPTH AND MARINE DEPOSITS OF THE PACIFIC OCEAN. 15 



nodules runs in a southeasterly direction to about 100° W. long., and 5° 

 south of the equator where it runs neai'ly due east off Aguja Point, its 

 eastern line then runs south, parallel to the South American coast. The 

 southern limit of the nodules as here given (PI. 3) is probably not its south- 

 ernmost limit, as the ' Challenger ' obtained manganese nodules a long way 

 south in the latitude of Valparaiso ; but nothing is known of the character 

 of the bottom on the area intervening between the lines of the ' Albatross ' 

 and ' Challenger.' The western and northern and eastern limits of the Eadi- 

 olarian ooze (PI. 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 Globiger- 

 ina 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 siliceous 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 ' Albatross,' and have been 

 spread westward by the prevailing southeast trades of the belt where they 

 are found (PL 4). . . . 



" Hauls of the trawl made off the Galapagos and at the western ex- 

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

 manganese nodules, with its Radiolarian ooze mud, Cetacean ear-bones, 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- 



