SIR JOHN MURRAY 173 



line lies somewhere about 100 fathoms deep, and 

 when we reach it we must proceed with the 

 utmost caution. We are now at the edge of 

 what Sir John named the " Continental Shelf/' 

 a rim which extends into the sea to varying 

 distances around the great land areas, a rim 

 indeed upon which our British Islands rest. 

 Beyond this Continental Shelf lies the Conti- 

 nental Slope, something of a gentle mountain-side, 

 but sometimes something of a precipice, which 

 descends smoothly or in terraces until the depths 

 of the Atlantic at about 2,000 fathoms are reached. 

 We are now on the bottom of the deep sea, and 

 the bottom of the deep sea is a monotonous, flat, 

 featureless greyish-buff expanse of uniform 

 scenery : Kipling's " great grey level plain of 

 ooze." We should traverse this featureless plain 

 for more than 2,000 miles, crossing, somewhere 

 about the middle, the mid-Atlantic Ridge before 

 beginning to ascend the long low slope leading 

 to the American land. Here we should pass 

 through the same zones of living organisms that 

 we traversed on the European side, but in a 

 reversed order. 



There are, however, pockets in the ocean, just 

 as there are mountains on the land, and the 



