148 PROF. E. HULL, LL.D., F.R.S., F.G.S., ON THE SCJIi-OCEANlC 



depends altoiL^etlier on the number and extent of the sound- 

 ings on the Admiralty Charts, we can only restore the sub- 

 marine featuj'es where these soundings occur in sufficient 

 number, and are extended to considerable depths. 



IMy subject naturally divides itself under two heads : 

 first, the western coast of Africa ; and, secondl}^ the Medi- 

 terranean basin. 



PART I. 



Submerged Physical Features off the Western 

 Coast op Africa. 



1. Tlie Continental Platform. — The gently sloping terrace 

 extending out from the coast of Western Europe known as 

 "The Continental Platform" loses nmch of its importance, 

 or sometimes altogether disappears, to the south of the 

 Straits and passes into a more or less gradual slope, from 

 the 100-fathom contour to that of 1,200 fathoms. This slope, 

 in all probability, consists of a succession of minor terraces 

 breaking off in cliffs ; but it would be difficult to determine 

 this with certainty unless with the aid of maps on a large 

 scale containing very numerous soundings. We were some- 

 what prepared lor this remarkable change in the character 

 of the submarine litoral of the two continents by tiio con- 

 traction of the Continental Shelf on approaching the vicinity 

 of Cape St. Vincent, where it has contracted to a breadth 

 varying from 10 to 20 miles. Directly opposite the Straits 

 of Gibraltar and again along the coast of Morocco, between 

 31° 10' N. and the Canary Islands, there occurs a broad 

 terrace extending for about 50-00 uiiles in breadth betw^een 



Fiql. Oecrion To illusl'raf'c ^orm oj" (Jcecxn bed V^.A|rica 



S.E 



J^ o r o c c o 



