742 THE JOURNAL OF GEOLOGY. 



ice sheets were confluent. From the Alps great glaciers descended to 

 the lowlands. (6) Eventually the ice of the third epoch disappeared 

 and temperate conditions succeeded. Of this change the best evidence 

 is furnished by the younger interglacial beds of the Baltic coast-lands. 

 (7) The fourth glacial epoch succeeded the third interglacial. During 

 this epoch the Lowlands of Scotland were submerged to a depth of 100 

 feet. The Highlands of Scotland had their glaciers, which in places 

 reached the sea. The Alpine glaciers flowed for long distances down 

 the great valleys, but fell far short of the dimensions reached by those 

 of the earlier epochs. From Scandinavia, the ice moved south to the 

 Baltic ridge in Germany. (8) Following the fourth glacial epoch 

 there was a fourth interglacial epoch, when deciduous trees spread far 

 north into regions where such trees no longer nourish. The Baltic 

 was converted into a great lake. Submergence followed, and the Bal- 

 tic became an arm of the sea, with a fauna indicative of a warmer cli- 

 mate than the present. (9) During the fifth glacial epoch there were 

 local valley glaciers in the British Isles, the position of which shows 

 that the snow line in Scotland had an average height of 2500 feet. 

 During this epoch Scotland was submerged to an extent of about fifty 

 feet. In the Alps, the fifth glacial epoch is marked by moraines of the 

 second so-called "post-glacial " stage. (10) The fifth interglacial epoch 

 was marked by the re-emergence of the land and the retreat of the valley 

 glaciers. Britain's area became wider than at present, but it is not 

 known that connection was made with the continent. (n) During 

 the sixth glacial epoch Scotland was submerged twenty or thirty feet 

 more than at present. The snow line then stood at an elevation of 

 something like 3500 feet in Scotland, and a few small glaciers existed 

 in the lofty mountains. It is to be noted throughout, that elevation 

 and amelioration of climate go together, while colder conditions 

 accompany subsidence. 



Concerning the origin of the loess Professor Geikie takes no 

 uncertain ground. He believes that it was primarily an aqueous 

 deposit, made during the closing stages of more than one glacial 

 epoch, but that the principal body of it was connected with the clos- 

 ing stages of the third epoch. Subsequent to its first deposition, it is 

 held that the wind shifted it from the position in which it was left by the 

 water, on a somewhat extensive scale. The fossils of the loess seem 

 to indicate that an arctic fauna was succeeded by a sub-arctic, and 

 this in turn by a temperate one. 



