096 



SCIENCE. 



[X. S. Vol. XXI. Xo. 540. 



indicate tliat an immense area of the bot- 

 tom of the eastern Pacific is covered with 

 manganese nodules, and that they play an 

 important part in the character of the bot- 

 tom, not only in the area covered by this 

 expedition; the ai'ea of manganese nodules 

 probably extends to the northwest of our 

 lines to join the stations where manganese 

 nodules Avere found l)y the Albatross in 

 1899 in the Moser Basin, on the line San 

 Franeisco-LIarquesas. This area may also 

 extend south of our lines Callao-Easter 

 Island, and join the line west of Valpa- 

 raiso, where the Challenger obtained man- 

 ganese nodules at many stations. I do not 

 mean to imply that the manganese nodules 

 are present to the exclusion of radiolarians 

 and of Globigerinte. It is probable that 

 the layer of nodules is partly covered by 

 them, and by the thick, sticky, dark choco- 

 late-colored mud which is found wherever 

 manganese nodules occur. 



During this expedition we sounded every 

 day while at sea and developed very fairly 

 that part of the eastern Pacific which lies 

 to the south and west of the line from Cape 

 San Francisco to the Galapagos and west 

 of a line from Galapagos to Aeapulco, lim- 

 iting an area occupied by the Albatross in 

 1891. The area developed by us is in- 

 cluded by a line 3,200 miles in length from 

 Aeapulco to Manga Reva and the area 

 north of a line from IManga Reva to Easter 

 Island and from Easter Island to Callao. 

 We developed on our line Galapagos to 

 Manga Reva the western extension of the 

 Albatross Plateau, and found it of a depth 

 varying from 1,900 to somewhat less than 

 2,300 fathoms in a distance of nearly 3,000 

 miles; but about half-way from the Gala- 

 pagos to Manga Reva we came upon a ridge 

 of about 200 miles in length with a depth 

 of 1,700 to 1,055 fathoms, dropping rapidly 

 to the south to over 1,900 fathoms. I pro- 

 pose to call this elevation Garrett Ridge. 



Our line from Manga Reva to Aeapulco 



continued to show the westei'n extension of 

 the almost level bottom of the eastern 

 Pacific. In a distance of 3,200 miles the 

 depth varied only about 400 fathoms. This 

 great area was practically a mare incog- 

 nitum. Three soundings in latitude 20° 

 south towards the Paumotus and five 

 soundings in a northwesterly trend from 

 Callao to Grey Deep are all the depths that 

 were known previously of this great ex- 

 panse of water. This existence of the great 

 plateau dividing Barber Basin along the 

 South American coast from Grey and 

 JNIoser Basins to the west is most interest- 

 ing. It recalls the division of the southern 

 Atlantic into an eastern and western basin 

 by a central connecting ridge. The Alba- 

 tross Plateau joins the western extension 

 of the Galapagos Plateau as developed by 

 the Albatross in 1891. 



The existence of a sounding of 2,55-l 

 fathoms near the equator in longitude 110° 

 west would seem to indicate a small basin 

 included in this plateau disconnected from 

 Grey Deep and Moser Basin by its exten- 

 sion to the west. How far west towards 

 these basins that extension reaches no 

 soundings indicate as yet. It is interest- 

 ing to note that along the Mexican coast 

 there are a number of deep basins lying 

 disconnected close to the shore just as we 

 found a number of disconnected deeps close 

 along the South American coast extending 

 from ofE Callao to off Caldera, Chili, op- 

 posite high volcanoes or elevated chains of 

 mountains. These basins and a great part 

 of the steep ]\Iexiean continental shelf are 

 deeper than the Albatross Plateau to the 

 south and form a deep channel separating 

 in places the plateau from the steep con- 

 tinental slope. The steepness of the con- 

 tinental shelf is well seen, especially off 

 Aeapulco and Manzanilla. One of the 

 small basins along the Mexican coast, with 

 2,661 fathoms, lies of¥ Sebastian Viscaino 

 Bay; another, with more than 2,900 fath- 



