10 



TEE BOTTOM OF THE SEA. 



there is again an abrupt def-cent of about 3300 feet ; 

 and from thence to Cuba the valley is only inter- 

 rupted by a chain of submarine hills of little im- 

 portance. Rounding Cuba, we find ourselves floating 

 above a perpendicular ravine, from 7000 to 8000 

 feet deep, betvv( en that island and Ilayti. Between 



90" 

 « 



80° 

 * 



70^ 



00° 



2(,o 



* 



[1716 sciile on t',e left hmd of the diagiam is in metres ; tue 

 depths are givai in equivalents of feet, j 



Fig 5. — Vertical Section of the Atlantic from Yucatan (coast of Mexico) 

 to Senegal. 



Hayti and Porto Rico, and between the latter and 

 the Windward Isles, the average r^epth is something 

 less than 7000 feet. Beyond the Lesser Antilles 

 there is nothing above the waves until we reach the 

 Cape de Verd Islands. Wlien we first spread sail 

 for that point, the plummet falls suddenly to a dep^h 



