io8 THE HAUNTS OF LIFE 



tively little is known of the vast zones between 

 the end of the light's reach and the floor of the 

 sea, so that, although they are included in the 

 idea of the Deep Sea, we may confine our- 

 selves in this study to the floor of the great 

 abysses. This is one of the largest haunts of 

 life, occupying about 100 million square miles, 

 i.e. more than a half of the whole earth's sur- 

 face; and it is the strangest. It is not difficult 

 to get comparatively near it, within a stone's- 

 throw of it, for we can toss a pebble into it 

 from the deck of a liner; but no one has ever 

 seen it. It is a bourne from which no trav- 

 eller can return. Yet we know a great deal 

 about it, thanks to the patience of explorers. 

 The world of the deep sea is very deep, for 

 the average depth of the ocean is 2^ miles; 

 and, as vast areas are comparatively shallow, 

 there must be other parts extraordinarily 

 deep. Just as the earth's crust has been 

 buckled into great mountains (the true moun- 

 tains, not those that are formed by the unequal 

 weathering of plateaux) , so it is dimpled down 

 into depressions. The very deep holes are 

 called " deeps " ; and the so-called " Challenger 

 deep" in the North-West Pacific is nearly 6 

 miles in depth, namely, 5269 fathoms. If one 



