THE GLACIAL PERIOD AND THE EARTH-MOVEMENT HYPOTHESIS. 25o 



as an appendix in Professor* G. Frederick Wright's Ice A ge in North 

 America. I may also mention, as treating this subject, in addition 

 to the paper in the American Geologist cited by Professor Geikie, 

 my articles in the American Journal of Science, III, vol. xli, pp. 33— 

 52, Jan., 1891, and Popular Science Monthly , vol. xxxix, pp. 665-678, 

 Sept., 1891. 



But if the supposed iriterglacial beds are more properly to be 

 referred to oscillations of the ice-front during a single glacial epoch, 

 as is held by Wright, Lamplugh, Falsan, and others, there would 

 be no such repetition of uplifting of the glaciated regions. 



The vertical extent of the uplift needed to reinstate the Glacial 

 period in Europe and North America, would be probably 3,000 to 

 5,000 feet, as Prof. T. G. Bonney has shown that an average 

 lowering of the temperature of Europe by 18° Fahr. and of the 

 northern part of North America by 13° would suffice. Though 

 Professor Geikie is inclined to relegate the time of land elevation 

 shown by the fjords to some epoch long antecedent to the Ice age, 

 I feel sure that they can be proved to be of Pleistocene age. In 

 North America submerged river valleys both on the Atlantic and 

 Pacific Coasts extend to the depth of 3,000 feet beneath the 

 present sea level ; and the Sogne fjord, the longest in Norway, has, 

 according to Mr. T. F. Jamieson (Geol. Mag., Ill, vol. viii, p. 390, 

 Sept., 1891), a depth of 4,080 feet. These glaciated countries 

 stood lately at least 3,000 to 4,000 feet above their present height. 

 This very remarkable condition and the equally extraordinary 

 accumulation of ice-sheets belong to the same Pleistocene period, 

 and I believe that they were causally related, the high altitude 

 being the cause of the ice-sheets. 



That the earth-movements which thus uplifted North America 

 and North-Western Europe, permitting streams to erode the fiords 

 and now submerged valleys, occupied the closing part of the 

 Pliocene period and culminated in the early part of the Pleistocene 

 or Glacial period, has been discussed and apparently demonstrated 

 by Prof. J. W. Spencer, Prof. Joseph Le Conte, and the present 

 writer. (Bulletin of the Geological Society of America, vol. i, 

 1890, pp. 65-70, 563-7; vol. ii, 1891, pp. 323-330, 465-476. 

 Le Conte's Elements of Geology, new edition, 1891, pp. 589-594. 

 Geol. Magazine, III., vol. vii, 1890, pp, 208-213, 492-7 ; vol. viii, 

 pp. 92, 262-272, 330.) 



In Europe, there is no better advocate of great earth-movements 



u 2 



