ANIMAL LIFE OF THE DEEP SEA BOTTOM 



I»I 



or the mud current will form a cascade falling down over the continental 

 slope. The current will now have become so much faster that, hke a 

 swiftly flowing river, it will carry with it sand and perhaps even larger 

 constituents. This is the sequence which it is imagined was the chief and 

 perhaps decisive factor in the formation of the vast steep-sided valleys 

 which cut their way from old and large water courses like the Congo 

 and Hudson rivers into the continental shelf, and which can be traced 

 right down into the deep sea just outside. 



If we apply this theory to the Philippine Trench there is good ground 

 for supposing that a turbidity current starting in the narrow shelf region 

 (and here there are typhoons, earthquakes, and submarine volcanoes to 



Sorted stones from the soft clay of the Philippine Trench. 



