14 THE DEPTH AND MARINE DEPOSITS OF THE PACIFIC OCEAN. 



. . . and as we approach Guam, ... in 2337 fathoms, we come upon de- 

 posits of fine volcanic sand. 



"No soundings were made by the 'Albatross' on the line from Guam to 

 Yokohama, as the line is parallel for a considerable length with that run by 

 the ' Challenger ' from the Admiralty Islands to Japan." 



The same report also includes a few remarks by Sir John Murray on the 

 bottom deposits,^ accompanied by two colored maps : one showing the dis- 

 tribution of the deposit types, and the other showing the depths, in the por- 

 tion of the Pacific traversed by the " Albatross." 



Fourth Expedition. — In the winter of 1904-1905 Dr. Alexander Agassiz 

 made his most recent expedition in the " Albatross " in the eastern tropical 

 Pacific. From San Francisco the " Albatross " proceeded to Panama, thence 

 to the Galapagos Islands, and to Aguja Point in Peru, thence out into deep 

 water and to Callao in Peru, thence to Sala y Gomez and Easter Island, then 

 back to Galapagos Islands, thence to Manga Reva in the Paumotu Archi- 

 pelago, and finally from Manga Reva to Acapulco. The following remarks 

 on the bottom-deposits are extracted from Dr. Agassiz's General Report of 

 the Expedition : " 



" Off Mariato Point [on the voyage from San Francisco to Panama] the 

 'Albatross' made two hauls in the vicinity of the stations where in 1891 she 

 found ' modern greensand ' in 555 and 782 fathoms. It was interesting to 

 find the greensand again, as the specimens collected in 1891 were lost in 

 transit to Washington. ... On the 2d [November] we left [Panama] for 

 Mariato Point to make a few additional trawl hauls in the region of the 

 greensand. In both the hauls made off Mariato Point greensand was 

 found, but not in the quantity obtained in 1891. . . . 



"The bottom of the area explored by the ' Albatross' in 1891 is covered 

 by green and brown mud mixed with masses of decayed and decaying vege- 

 table matter. South of this area we come upon the great tracts of the 

 Eastern Pacific, the bottom of which is covered by manganese nodules. 

 The extent of this tract is shown in Plate 3, where are given the northern 

 and eastern limits of the manganese nodules as well as its southern limit 

 extending from Easter Island to Manga Reva. From the northern extrem- 

 ity of Moser Basin the line forming the northern limit of the manganese 



1 Mem. Mus. Comp. Zool, Vol. XXVI., 1902, pp. 109-111, maps 1" and l^. 



2 lUd., Vol. XXXIII., 1906, pp. xi., xii., 5 et seq. 



