x.] THEOEY OF DENUDATION. 245 



it are other similar glens, parted from it by long 

 narrow ridges : these also must be explained on the 

 same hypothesis ; but they cannot. For there could 

 not have been surf ace- drainage to make them all, or a 

 tenth of them. There are no other possible hypotheses ; 

 and so he must fall back on the original theory the 

 rain, the springs, the brook ; they have done it all, 

 even as they are doing it this day. 



But is not that still a hasty assumption ? May not 

 their "denuding power have been far greater in old 

 times than now ? 



Why should it ? Because there was more rain then 

 than now ? That he must put out of court ; there is 

 no evidence of it whatsoever. 



Because the land was more friable originally ? 

 Well, there is a great deal to be said for that. The 

 experience of every countryman tells him that bare or 

 fallow land is more easily washed away than land under 

 vegetation. And no doubt, when these gravels and 

 sands rose from the sea, they were barren for hundreds 

 of years. He has some measure of the time required, 

 because he can tell roughly how long it takes for sands 

 and shingles left by the sea to become covered with 

 vegetation. But he must allow that the friability of 

 the land must have been originally much greater than 

 now, for hundreds of years. 



But again, does that fact really cut off any great 

 space of time from his hundreds of thousands of years? 

 For when the land first rose from the sea, that glen 

 was not there. Some slight bay or bend in the shore 

 determined its site. That stream was not there. It 

 was split up into a million little springs, oozing side by 

 side from the shore, and having each a very minute 



