Summary. 6 1 7 



sider, if true and I firmly believe it to be true that 

 so many of those hollows in which lakes lie have 

 been scooped out by the slow and long-continued passage 

 of great sheets of glacier ice, quite comparable to those 

 vast masses that cover the extreme northern and 

 southern regions of the world at this day. 



The water-drainage of the country is likewise seen 

 to be dependent on geological structure. Our larger 

 rivers chiefly drain to the east, and excepting the Severn, 

 the Dee (Wales), the Mersey, the Solway, and the Clyde, 

 the smaller ones to the west, partly because certain axes 

 of disturbance happened to lie nearer our western than 

 our eastern coasts. Again, the quality of water in these 

 rivers depends, as we have seen, on the nature of the 

 rocks over which they flow, and of the springs by which 

 they are supplied. 



Then, when we come to consider the nature of the 

 population inhabiting our island, we find it also to be 

 greatly influenced by this old geology. The earlier 

 tribes were in old times driven into the mountain 

 regions in the north and west, and so remain to this 

 day still speaking their own languages, but gradually 

 mingling now, as they did before, with the masses 

 of mixed races that came in with later waves of 

 conquest from other parts of Europe. These later 

 races settling down in the more fertile parts of the 

 country, first destroyed and then again began to 

 develop its agricultural resources. In later times they 

 have applied themselves with wonderful energy to turn 

 to use the vast stores of mineral wealth which lie in 

 the central districts. Hence have arisen those densely- 

 peopled towns and villages in and around the Coal- 

 measure regions, where so many important manufactures 

 are carried on. Yet in the west, too in Devon and 



