THE GULF BTBEAM. 389 



Bank, just before the Stream runs off uncontrolled into the Atlantic, the 

 strait is 53 miles in width, and the soundings, at distances of about 5 miles 

 apart, are as follow : — 



20 95 176 250 341 416 439 395 347 294 lOO fathoms. 



The depth of 100 fathoms is found within 1 mile of Memory Rock, and 

 it will be noticed that here, as elsewhere in the Straits, the Eastern side 

 of the channel is the deeper. 



(379.) The Stream emerges from the Straits over a bank which appears 

 to have still shallower soundings than on the last section, and with refer- 

 ence to this. Commander Bartlett, U.S.N., makes the following remarks : — 

 " Instead of a deep- channel which had previously been reported, our 

 soundings show a nearly level plateau extending from a point to the 

 Eastward of the Bahama Banks to Cape Hatteras. Off Cape Cana- 

 veral it is nearly 200 miles wide, and gradually decreases in width to the 

 Northward until reaching Hatteras, where a depth of more than 1,000 

 fathoms is found 30 miles off shore. This plateau has a general depth of 

 400 fathoms, suddenly dropping on its Eastern edge to 2,000 fathoms. 



" The course of the Gulf Stream can almost be traced by the character 

 of the bottom. On each side the sounding cylinder brought up ooze, but 

 in the strength of the current the hard bottom was washed nearly bare, 

 the specimens being small broken pieces of disintegrated coral rock."* 



Northward of the Straits some curious variations of temperature are 

 found in crossing the axis of the Stream, as will be presently explained. 



Lieutenant Craven, U.S.N., was under the impression, from his series 

 of soundings off Charleston and Cape Canaveral, in the Corwin, in 1853, 

 that the bed of the ocean was here of an undulating character, with two 

 ranges of submarine hills at 96 and 136 miles off Charleston, and 1,800 

 and 1,500 feet high respectively. On the Canaveral section the inner range 

 was said to be 68 miles from the coast. As stated above, no trace of these 

 submarine hills could be found when more perfect apparatus was used, 

 but the bottom was found to be a plateau. 



Lieutenant Craven noticed ripples on the Charleston section, thought 

 to be in connexion with the irregularities of the bottom. Similar ripples 

 were observed on the Sandy Hook section and on the Montauk section in 

 1845, and were compared to the " rips " on the Nantucket Shoals. 



(380.) From Florida Strait, then, nearly as far as Cape Hatteras, tha 

 axis of the Gulf Stream has been found to run over a plateau with a general 

 depth of 400 fathoms. To the Northward of this, the ocean is very deep. 

 At 200 miles Eastward of Cape Hatteras the depth is 2,500 fathoms ; at 

 150 miles Eastward of Cape Hanlopen, 1,500 fathoms ; at 180 miles E.S.E. 

 of Nantucket, off the S.E. point of George Shoal, 1,350 fathoms ; at 230 

 miles Eastward of Nantucket, off the Eastern edge of George Shoal, 1,340 

 fathoms ; and at 180 miles Southward of Halifax, and 40 or 50 miles 

 S.S.E. of Le Have Bank, 1,250 fathoms. Between this latter sounding 

 and Bermuda the depths vary between 2,000 and 3,000 fathoms. These 



* TIriitod States Coaat Survey Eeport, 1332, Appeaiix 11. 



