POPULAR MISCELLANY. 



279 



England, one from Belfast, Ireland, three 

 from Massachusetts, two from Ohio, two 

 from Illinois, and one each from Iowa and 

 Colorado. Of the twenty-seven papers by 

 professional geologists, twelve were from the 

 United States and three from Canada, the 

 twelve others being as follows : from Brazil, 

 two ; Venezuela, one ; England, Scotland, 

 and Germany, each two ; and Sweden, Nor- 

 way, and Switzerland, each one. Besides 

 the formal papers, interesting discussions fol- 

 lowed, and the programmes for three of the 

 days ended with questions for special dis- 

 cussion, these being, Are there any natural 

 geological divisions of world-wide extent ? 

 What are the principles and criteria to be 

 observed in the restoration of ancient geo- 

 graphic outlines? and similarly, What are 

 the principles and criteria to be observed in 

 the correlation of glacial . formations in op- 

 posite hemispheres ? Among the geologists 

 present at this Congress were Prof. Dr. 

 Groth, of Munich ; Mr. Hjalmar Lundbohm, 

 of Stockholm ; Dr. A. R. C. Selwyn, Director 

 of the Geological Survey of Canada; the 

 venerable Prof. James Hall, whose work in 

 geology began sixty years ago; Profs. Le 

 Conte, Chamberlin, Salisbury, Lindahl, Wal- 

 cott, H. S. and G. H. Williams, N. H. Win- 

 chell, G. F. Wright, and many others from 

 the United States. 



Subdivisions or Unity of the Glacial 

 Period. The final day of the World's Con- 

 gress on Geology was devoted to papers on 

 the Glacial period, of which eight were pre- 

 sented. Brief notes of these papers and of 

 the ensuing discussions will be of popular 

 interest, as they all were specially directed 

 to the recently much debated question wheth- 

 er the ice age comprised two or several 

 glacial epochs, separated by warm intervals, 

 as has been urged by Croll, Geikie, Wahn- 

 schaffe, Penck, De Geer, Chamberlin, McGee, 

 and others, or was a single and continuous 

 period of glaciation, as maintained by Dana, 

 Wright, Upham, Lamplugh, Kendall, Falsan, 

 Hoist, Nikitin, and others. 



The first paper of this series was by Prof. 

 James Geikie, of Scotland. This distin- 

 guished glacialist concludes, from his obser- 

 vations in Great Britain and their correla- 

 tion with the northern drift-covered portion 

 of continental Europe, that no less than five 



distinct glacial epochs are recognizable there, 

 separated by long times of interglacial tem- 

 perate climate. These alternations are held 

 to be in accord with Dr. James Croll's astro- 

 nomic theory of the causes of the Ice age, 

 affording indeed a demonstration of the truth 

 of that theory. 



Mr. Hjalmar Lundbohm, of Sweden, giv- 

 ing the results of his own studies and of the 

 more extended observations of Baron De 

 Geer in that country, thought that good evi- 

 dence is found for two epochs of ice accumu- 

 lation and drift deposition. During the first 

 glaciation the Scandinavian ice-sheet flowed 

 outward over the northwestern half of Rus- 

 sia and the northern half of Germany, while 

 southwestward it covered the basin of the 

 North Sea and was confluent with the British 

 ice. The later glaciation, in which a great 

 ice-lobe stretched south and southwest over 

 the basin of the Baltic Sea, formed conspicu- 

 ous moraines in Finland, northern Germany, 

 and southern Sweden. Since the retreat of 

 this ice-sheet Scandinavia has been differ- 

 entially uplifted to a maximum amount of 

 about one thousand feet in the center of the 

 peninsula, and the Baltic Sea has been alter- 

 nately open to the ocean and closed from it, 

 so that for some time it was a fresh-water 

 lake. 



Mr. Andrew M. Hansen, of Norway, also 

 declared in favor of two glacial epochs, each 

 of them including two or more stages of ice 

 advance and retreat. The glacial drift of 

 Norway, however, was described as affording 

 little testimony of an interglacial epoch, 

 which this author accepts from its stratified 

 deposits underlain and overlain by till in 

 other parts of Europe. 



Dr. Albrecht Heim, of Switzerland, from 

 the glacial drift with intercalated beds con- 

 taining lignite coal and plentiful plant re- 

 mains in valleys of the Alps, confidently as- 

 serted that the glaciers must three times 

 have advanced far beyond their present 

 limits. The second advance was the far- 

 thest, and was doubtless contemporaneous 

 with the maximum extension of the ice-sheets 

 of Scandinavia and Great Britain. 



Dr. Robert Bell spoke of the glaciation 

 of Canada, which was wholly enveloped by 

 the North American ice-sheet, excepting a 

 tract west of the lower Mackenzie Valley and 

 perhaps a narrow area adjoining the east 



