450 ON THE ACTION OF RUNNING-WATERS, 



reetness of observation and of reasoning, which is re^ 

 markable only, because it has not been adopted by alt 

 naturalists ; and few have bestowed the unremitting at- 

 tention upon the subject which this respectable geologist 

 has done. He has shewn, that the destructive action of 

 the waters upon steep shores, and other coasts or ab- 

 rupt cliffs, was considerably restrained by the very con- 

 sequences of this action ; that the debris which accumu- 

 lated protected the lower parts of these coasts from the 

 action of the water, or gradually reduced an abrupt coast 

 to a very inclined and permanent slope. 



Next, to torrents, to rapid and large rivers, and to 

 waves, it is to currents that a great influence on the 

 earth's surface has been attributed, an influence which 

 a highly gifted naturalist, Buffon, has employed to ex- 

 plain all the inequalities of the earth's surface. 



Our knowledge of the action of currents is less precise 

 than that which we possess of rivers. But if we cannot 

 so visibly demonstrate that, in no circumstance similar to 

 those which -we have specified, do they scoop out the 

 bottom of the sea into valleys, nor form any mountains, 

 we can, at least, conjecture with much probability, and 

 maintain, that we have no direct and constant proof of 

 that action. 



4. Action of Currents. 



No one doubts that currents, near coasts, heap up 

 upon the beach, at the mouth of rivers and harbours, 

 pebbles, sand, gravel, mud, or other transportable mat- 

 ters, whether these currents constantly exist, or simply 



