302 The Realm of Nature CHAP. 



388. Lake District of Northern Europe. North of 

 the Baltic the long slope of the peninsular mass of land, 

 including Scandinavia and Finland, is toward the south. 

 The great Lake Ladoga, which discharges its overflow by 

 the short swift Neva into the Baltic, receives the drainage 

 of a vast lake district Lake Onega on the north, Lake 

 Ilmen on the south, Lake Saima and innumerable con- 

 nected lakelets on the west, all draining to it. At Imatra, 

 on the river joining Lakes Saima and Ladoga, the most 

 impressive cataract in Europe is formed in a nearly flat 

 country by the water pouring through a narrow and steep 

 bed of hardest granite, which converts the course for more 

 than a mile into a thunderous mass of feathery foam and 

 leaping yellow waves. All the lake-basins of this district are 

 due to glacial action, and date from the same period as those 

 of North America. They are, as a rule, shallow, some 

 having been scooped out of a flat floor of crystalline rock, 

 while others are formed by the irregular accumulation of 

 glacial detritus ( 332). About one-sixtieth of the area 

 of Europe is covered with lakes, but in the district of Fin- 

 land the proportion is one-tenth. 



389. The British Islands. An upheaval of 300 feet 

 would convert the bed of the North Sea, south of a line 

 drawn from St. Abb's Head to the Skaw, into a low plain 

 continuous with that of England and of Northern Europe. 

 During the evolution of Europe elevation and subsidence 

 have repeatedly raised the whole region into land and again 

 lowered it under water. Viewed as a whole, the island of 

 Great Britain is higher toward the west than the east 

 (see Plate XVI.) The watershed lies near the west coast, 

 giving a long east slope traversed by the longest rivers. 

 The east coast is comparatively smooth, with occasional 

 wide funnel-like estuaries and scarcely any islands ; while 

 the west coast is very deeply indented by winding fjords or 

 sea-lochs, and many groups of large and often lofty islands. 

 No true mountain ranges can now be traced in the British 

 Islands ( 303, 329). Glacial action has been traced over all 

 the British Islands except the extreme south of England, and 

 the existing configuration has thus been modified in most 



