POST-TERTIARY PERIOD. 541 



The course of the stones, gravel, and sand in each case was 

 towards the equator. 



In Europe, they crossed the Baltic from Scandinavia to Germany, 

 many of great size ; and other Scandinavian rocks were carried to 

 the coasts of Britain. The general direction is from the north- 

 ward, or between north and northwest. 



The distance of travel varies from five or ten miles to five or six 

 hundred. 



Scratches are also common in the Drift regions of Europe, and 

 are evidently part of the results of the Drift movement. 



Fiord Valleys. 



Another great fact that belongs to the Drift latitudes on all the 

 continents, and may have the same origin, is the occurrence, on 

 the coasts, of fiord valleys, — deep, narrow channels occupied by the 

 sea, and extending inland often for 50 or 100 miles. This geogra- 

 phical connection with the Drift is a striking one. Fiords occur 

 on the northwest coast of Europe, from the British Channel north, 

 and abound on the coast of Norway. They are remarkably dis- 

 played on the coasts of Greenland, Labrador, Nova Scotia, and 

 Maine. On the northwest coast of America, from the Straits of De 

 Fuca north, they are as wonderful as along Norway. On the coast 

 of Sftuth America, they occur in Drift latitudes from 41° S. Drift 

 latitudes are therefore identical nearly with the fiord latitudes. 



General Observations. 



Origin of the phenomena of the Glacial epoch. — The Drift epoch 

 is usually called the Glacial epoch, under the idea that ice, either 

 in the form of icebergs or glaciers, was concerned in the transporta- 

 tion of the boulders, pebbles, and earth. Ice may float masses of 

 many thousand tons' weight, when in the condition of an iceberg, 

 for twenty, thirty, or hundreds of miles ; and so glaciers, as in the 

 Alps, may bear along great masses of rock or earth. But simple 

 running or moving water is comparatively feeble for such results. 

 There are, then, two theories, the Iceberg and the Glacier. The 

 former supposes large parts of the continents under the sea ; the 

 latter places the same regions above the sea, and perhaps at a 

 higher elevation than now. They thus diverge at the outset. 



1. Iceberg theory.— (I.) The Iceberg theory supposes a submergence 

 in New England of 2000 to 4000 or 5000 feet. It requires that the 

 submerged area should have extended wherever the drift occurs ; — 



