108 THREE CRUISES OF THE '' BLAKE." 



varied than that of continental areas. As a general rule we 

 find that the continental masses form platforms sinking quite 

 rapidly into the adjoining oceanic basins. The hundred- 

 fathom line may extend far out to sea in some cases, as, for 

 instance, in the northwestern extremity of France, where it unites 

 Great Britain and France. On the east coast of the United 

 States an extensive plateau — the continuation, in other words, 

 of the continent below the surface — follows the hundred-fathom 

 line along our southern coast to the extremity of George's 

 Bank, expanding again farther north, oif the coasts of Nova 

 Scotia and of Newfoundland, so as to include Sable Island Bank 

 and the Great Banks of Newfoundland within the true conti- 

 nental line. In the case of the West India Islands, this line 

 discloses a connection between adjoining islands which the mere 

 study of the land map would fail to show. But the hundred- 

 fathom line is simply the edge of the continental plateau along 

 which the detritus brought from the continents by its rivers is 

 deposited. Upon its slope the fauna characteristic of any 

 region extends into deep water, gi-adually becoming modified 

 in its character by the temperature of the region into which it 

 finds its way. Beyond this hundred-fathom line there is usually 

 a very rapid descent into deep water. This line may indeed be 

 considered as the true continental outline, the edge of the shelf 

 which forms the continuation of the continental masses, below 

 the surface and beyond those shore lines which we are accus- 

 tomed to consider as the true boundary between land and water. 



