434 Lakes. 



to account for than the origin of many lakes. When 

 thought about at all it is easy to see that lakes are the 

 result of the formation of hollows, a great proportion of 

 which can be easily proved to be rock-basins that is 

 to say, hollows entirely surrounded by solid rocks, the 

 waters not being retained by mere loose detritus. But 

 the great difficulty is, how and why were such large 

 numbers of these rock-basins made in special regions ? 

 I have often been so much misunderstood and mis- 

 represented in this matter, that those who had not 

 read my early papers on the subject might easily have 

 supposed that I attributed the origin of all lake-basins 

 to glacial erosion, and that in spite of my having, in 

 print, formally disclaimed any such idea. It is not 

 likely that any man could have entertained it who 

 had seen lakes in old volcanic craters, who was familiar 

 with the fact of subsidences in old and new volcanic 

 regions, and who, besides, expressly stated that there 

 were doubtless other kinds of lakes, the origin of which 

 he probably knew nothing about. 



A great many lakes lie in valleys, and many persons 

 in times past and present have been easily satisfied as 

 to the causes that produced mountains, valleys, and 

 lakes. To the uneducated, the first and obvious ex- 

 planation is, that in all its grand features the world was 

 originally made very much as it now stands. With the 

 half educated, even in geology, the explanation is, that 

 the irregularities of the surface have been caused purely 

 by dislocations, or, going one step further, that deep 

 openings ( were primarily due to cracks which took place 

 during the various movements which each chain has 

 undergone at various periods,' the meaning of which 

 I conceive to be, that mountain valleys necessarily lie 

 in lines of curvature, dislocation, and fracture, and that 



