174 



ARE SOILS ENEICHED, IMPOVERISHED, pt. in. 



as a ties! rue tive power, is the producer, the replacer, of 

 continents. And the cause which caused the valleys is 

 in as full operation at this moment as ever it was. In- 

 deed, valleys only exist in the dissolution of hills ; that 

 is, in the gradual and eternal wash by rain of tlie 

 existent earth into the sea. 



Reso]u(aqne terus 

 In liquidas rortscit aquas, 



and 



Tellus glomeraia cogitur nnda, 



are as true at this instant as in the time of Pythagoras, 

 or as they have been and will be (shall I say ?) ever- 

 more. 



Bat in reference to the marine theory in general, 

 that the action of waves on land slowly emerging from 

 the deep should have a tendency to wash away soft 

 parts and to leave hard parts, I can conceive ; but to 

 attribute the formation of our valleys to this cause, as 

 Lyell does, is to suppose that the materials of all the 

 valleys running from the tops of all the heights on the 

 globe were originally softer than the materials of the 

 intervenino^ ridi^es ; but in almost all cases we can see 

 that this is not so, by the corresponding strata on the 

 opposite sides of valleys. 



In regard to currents : a current might decapitate a 

 continent as it rose, supposing equal softness of mate- 

 rials, or it might scoop a horizontal groove of any size 

 or depth, or (granting lines of hard intervening ridges) 

 many grooves ; but they must all be horizontal, and in 



