VI. 



The Underground Waste of the Land. 



(GEOGRAPHERS and geologists are alike interested in the origin 

 7 of the physical features of the land ; but their sympathies 

 become united only when we treat of the actual processes of 

 sculpture. To the geologist the evolution of scenery is an exceedingly 

 complex subject, for many of the features marked out in ancient 

 epochs have been buried up by subsequent sediments and afterwards 

 revealed by denudation. In the long and varied history of the sub- 

 ject the geographer is apt to manifest impatience, for he cares little 

 about the age of the rocks, so long as he understands their relation 

 to the form of the ground, and the influences that have contributed to 

 produce the present shape of hill and dale, lake and river. 



In this country the waste along our coasts, especially along the 

 eastern and southern shores, is manifest ; but when we study the 

 inland features and find evidence of so many ancient earthworks, 

 it would seem that the surface of the land has been but little modified 

 during the past four or five thousand years. 



The power of rain and rivers in wearing away the surface of the 

 land is scarcely realised until statistics are presented to us of the 

 amount of solid matter annually carried to sea by our rivers. 

 From some areas in England and Wales as much as 150 (or even 200) 

 tons per square mile may be removed each year, but the result is 

 imperceptible, for it means a lowering of the general level of the land 

 of about one-tenth of an inch in a century. 



More conspicuous are the local evidences of destruction that 

 may be seen in the occasional landslip and in the screes of fragmentary 

 rock at the foot of crag and mountain. The material is dislodged by 

 the mechanical action of frost and rain, and in some situations, 

 as along the Pass of Brander, below Loch Awe, it is carried away by 

 torrential streams, and the rounded fragments go to form beds of 

 gravel. Again, after heavy rains, the turbid streams in the lowlands 

 plainly indicate the kind of denudation that is taking place. 



The loss of material that is carried away in solution is rarely 

 made manifest, except in the case of caverns, and by sinkings of the 

 ground in limestone-areas ; or by the artificial removal of brine from 

 the salt regions of Cheshire, whereby great subsidences have been 

 caused. Even the Bath hot-springs, which do not contain a very 



