Soil-Carriera 45 



with it a heavy load of mud, ground from mountains 

 3,000 miles away, which it has deposited ia some 

 places to a depth of 300 feet. 



And so again, on a smaller scale, the low plain at 

 the head of the Lake of Geneva is formed of mud from 

 the mountains, which the Rh6ne has brought down 

 and deposited in the lake, adding to it year by year, 

 until it has risen above the water, and Port Vallais, 

 which stood on the margin of the lake in Roman times, 

 now lies a mile and a half inland. 



Inundations are caused usually either by excessive 

 rain, such as that which falls periodically in Abyssinia, 

 or by the melting of the snow in spring ; but passing 

 mention must here be hiade of certain inundations 

 brought about by very different causes, and which, 

 though on a very much smaller scale than these others, 

 are yet said to have altered some of the valleys of 

 North America to a quite incredible extent. 



These inundations have been caused by the beaver. 

 The beaver is retreating further and further before 

 man ; and though it still inhabits the North of Europe 

 and Asia, it is nowhere now so plentiful as here in 

 North America, where, also, the effect of its work in 

 the past may best be observed. 



But the beaver once abounded in England and 

 Wales, and indeed throughout the greater part of 

 Europe, as the names of many places, such as 

 Beverley, Beverstone, Biverbike, and many others, 

 plainly show. What we see of its work in America, 

 therefore, is probably only a specimen of what it has 

 done wherever it has been undisturbed. Here, at all 

 events, thousands of acres of land have been sub- 

 merged, at one time and another, as the result of its 



