636 REVIEWS 



of distinct stages, however, removes from the advocacy of the doc- 

 trine of "unity" the gravest objection which has heretofore lain 

 against it, viz., neglect of important discriminations and confusion of 

 formations diverse in age and nature. The degree of separation of 

 the glacial stages recognized by Mr. Upham iinds its maximum illus- 

 tration in the retreat of the ice after the Kansan stage for a dis- 

 tance of 500 miles and its readvance about 350 miles, an oscillation 

 which, if applied to Greenland, would eliminate and reproduce its 

 ice-sheet. 



Mr. Upham still urges the hypothesis of elevation as the chief 

 cause of the Pleistocene glaciation. It seems not a little infelicitous 

 to urge this doctrine in a work on Greenland, since the testimony of 

 that region weighs heavily against the doctrine. At intervals along a 

 thousand miles of the western coast it was observed by the present 

 writer that a notable part of the mountainous border is rugged and 

 angular and betrays no evidence of ever having been overridden by 

 inland ice. A small driftless area was also discovered on the very 

 border of the inland ice on Bowdoin Bay between latitudes 77° and 78"^ 

 which shows more unequivocally that there has never been a general 

 extension of the Greenland ice-sheet westward much beyond its pres- 

 ent outline. The evidence of former elevation is as pronounced in 

 Greenland as in any part of the northern hemisphere. It appears, 

 therefore, that in this land of glaciers par excellence, the former eleva- 

 tion of two or three thousand feet or more was not accompanied by 

 any great extension of glaciation, if indeed it was accompanied by any 

 general glaciation at all. It appears, therefore, that the epeirogenic 

 theory is weak on its most radical point — coincidence of elevation 

 with glaciation — in its most promising region. To the writer it seems 

 unfortunate that the public should be so industriously indoctrinated in 

 a theory of the cause of the Ice Age which encounters such serious 

 and seemingly fatal testimony in the very home of glaciation. 



T. C. C. 



Ice-Work, Present and Past. By T. G. Bonney. International 

 Scientific Series. New York : D. Appleton & Company. 



For the past twenty years the author has written chiefly on petro- 

 logical subjects. Many of his earlier papers, however, dealt with ice 

 and its work, and this book is an expression of the revival of that 



