CENOZOIC TIME — QUATERNARY. 975 



not glaciated. Deep lake basins in the harder rocks are not regarded as 

 among the possible results of glacier excavation, their existence in glaciated 

 regions being generally due to the damming of channels by the glacial 

 deposits and sometimes to changes in level. 



Thus a glaciated country bears everywhere the marks of the ice. The 

 more delicate marks — the scratches or groovings — would be now universally 

 visible over the exposed rocks, were it not for their removal by weathering. 

 On the harder rocks they may generally be found by removing the soil. 



The effects of abrasion and degradation are apparent also in the grander 

 work of shaping mountains and excavating deep valleys ; but in the pro- 

 duction of these results, the ice was aided to a very large extent by 

 the subglacial streams. Moreover, the degradation and excavation were 

 carried on as effectually, or more so, by the later floods from the melting 

 ice. The fiords are attributed to the ice ; but the waters from the melted ice 

 were the main eroding agent, while the ice worked chiefly by lateral abrasion. 



FOREIGN. 



In Europe the region of the Scandinavian Mountains was the great 

 center of the accumulation and distribution of ice and bowlders. There 

 were also some local centers : as in the Scotch Highlands ; in the Alps, Urals, 

 Caucasus, and Pyrenees ; in the mountains of Auvergne, Lyonnais, and Beau- 

 jolais, in France. At the time of maximum glaciation the ice was continuous 

 from Scandinavia westward over the British Isles, eastAvard to the Urals, and 

 southward almost to the parallel of 50°. The ice spread over nearly 55° of 

 longitude, which is 10° more than was true in North America between the 

 coast of Labrador and the Coteau des Prairies; but the degrees are much 

 shorter, as the southern limit of tlie area lay 10° to 13° farther north than 

 the iSTorth American. This difference in southern limits corresponds with 

 the existing difference in the positions of isotherms on the two continents. 

 The glacier did not cover England south of the Thames, nor any part of France. 

 Brussels and Dresden were near its limit. The accompanying map (Fig. 

 1552), by J. Geikie (from his paper on The Glacial Succession in Europe, 

 Roy. Soc. Eclinb., 1892) shows, by the paler shading, the supposed limits 

 of the ice during the time of maximum glaciation, and by the darker color, 

 those during the epoch of the later Baltic glacier. 



The glacial drift crossed the Baltic from Scandinavia eastward and 

 southeastward over north Russia, the Baltic Provinces, and Moscow, reach- 

 ing nearly as far south as Kieff ; and southward over Denmark, part of Ger- 

 many, and Poland. It spread southwestward over the Faroe and Shetland 

 Islands and to the coast of Norfolk, in England. The distance of travel 

 varied from five miles, or less, to 500 or 600. There is evidence also of trans- 

 portation toward the Polar regions. 



In Great Britain, the movements were mainly in the direction of the 

 slopes of the mountains and their valleys, the drift radiating from different 



