AGASSIZ : LETTERS TO THE HON. GEORGE M. BOWERS. 83 



rent on the line Manga Reva to Acapulco agreed well with those taken in 

 the same current to the east. 



The samples of the bottom obtained by the soundings taken by the 

 expedition or gathered in the mud-bag and in the trawl indicate that an 

 immense area of the bottom of the eastern Pacific is covered by man- 

 ganese nodules, and that they play an important part in the character 

 of the bottom, not only in the ai'ea covered by this expedition, but also 

 that the area of manganese nodules probably extends to the northwest 

 of our lines to join the stations where in 1899 manganese nodules were 

 found by the "Albatross " in the Moser Basin, on the line San Fran- 

 cisco to Marquesas. This area may also extend south of our line Callao to 

 Easter Island, and join the line west of Valparaiso where the " Chal- 

 lenger " obtained manganese nodules at many stations. I do not mean 

 to imply that the manganese nodules are present to the exclusion of 

 Radiolarians and of Globigerinae. It is probable that the layer of 

 nodules is partly covered by them, and by the thick sticky dark choco- 

 late-culored mud which is found wherever manganese nodules occur. 



During this expedition we sounded every day while at sea, and de- 

 veloped 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 Galapagos to Acapulco, limiting an area occupied by 

 tlie "Albatross" in 1891. The area developed by us is included by a 

 line 3200 miles in length from Acapulco to j\Ianga Reva, and north of a 

 line from Manga Reva to Easter Island and from Easter Island to Callao. 

 We developed on our line Galapagos to Manga Reva the western exten- 

 sion of the Albatross plateau, and found it of a depth varying from 

 1900 to somewhat less than 2300 fathoms in a distance of nearly 3000 

 miles ; but about half-way from the Galapagos to Manga Reva we came 

 upon a ridge of about 200 miles in length with a depth of 1700 to 1055 

 fathoms, dropping rapidly to the south to over 1900 fathoms. I pro- 

 pose to call this elevation tlie "Garrett Ridge." 



Our line from Manga Reva to Acapulco continued to show the west- 

 ern extension of the almost level bottom of the eastern Pacific. In a 

 distance of 3200 miles the depth varied only about 400 fathoms. This 

 great area of the eastern Pacific was practically a mare incognitum. 

 Three soundings in latitude 20° S. toward the Paumotus and five sound- 

 ings in a northwesterly trend from Callao to Grey's Deep are all the 

 depths that were previously known in this great expanse of water.^ The 



1 These soundings were made (one) by tlie Italian S. " Vittor Pisani " in 1882 ; 

 (three) by the " Silverton " in 1893 ; (four) by the U. S. S. " Alaska," and two east 

 of the Paumotus by the H. B. M. S. "Alert." 



