CHAP, v.] GENERAL CONCLUSIONS. 247 



general results were arrived at which are of great interest even 

 in their present crude form. 



1 propose in this chapter to summarize these results, giving 

 briefly a general outline of the conditions as to the contour 

 of the bottom of the ocean, tlie nature of the deposits which 

 are being laid down on the bottom, the general distribution 

 of temperature, the direction and force of surface and subma- 

 rine movements of the water, and the nature and distribution 

 of the deep-sea fauna, according to my present impressions; 

 premising that these may be modified to a certain extent by 

 further study of the materials in our hands. I will, however, 

 confine myself at present, as far as possible, to the facts which 

 appear to be ascertained with some approach to certainty. 



The Contour of the Bed of the Atlantic. — During the first 

 few days of our cruise we verified many previous observations 

 to the effect that, after passing a comparatively narrow, shal- 

 low belt, the water deepens rather suddenly along the coasts 

 of Europe and I^orth Africa, to between 2000 and 2500 fath- 

 oms, a peculiar ridge, first observed by the Swedish corvette 

 Josephine, and lately by the United States sloop Gettysburg, 

 running down in a south-westerly direction from about Cape 

 Koca, including the Josephine Bank and Madeira, and giving 

 its western boundary to a tongue of deep water which passes 

 in a north-easterly direction between Madeira and the main- 

 land toward Cape St. Vincent. (See Frontispiece.) 



From Teneriffe westward, except at one spot about 160 miles 

 south-west of the Island of Ferro, where we sounded in 1525 

 fathoms on the top of a ridge, the water gradually deepened 

 to the westward to the depth of 3150 fathoms at the bottom 

 of a wide valley, which extends more than half-way across the 

 Atlantic. About long. 43° W. the floor began to rise, and at 

 long. 44° 39' "W". we sounded in 1900 fathoms on the top of a 

 gentle elevation. Farther to the westward the depth again 

 increased, and in long. 61° 28' N. we sounded in 3050 fathoms 



