CONDITIONS OF PAST GLACL4.TI0N DISCUSSED. 345 



earth's surface. One of these regions is Western Europe, the other North- 

 eastern North America. Under the former designation are embraced all the 

 higlier mountain groups and ranges along the Atlantic and also those which 

 extend east from the Atlantic and north of the Mediterranean to about 

 the head of the Adriatic. It includes the entire Scandinavian Rans:e, the 

 Highlands of Scotland and of Ireland, the Pyrenees, the Alps, and also, to a 

 certain extent, some of the ranges of less importance north of the Alps, par- 

 ticularly the Yosges Mountains, and perhaps the higher summits of Central 

 France. It may seem strange that these different regions should be grouped 

 together; but if the reader will look at a globe and see how relatively near 

 together the various mountains named lie with reference to each other as 

 compared witli the entire area of the land of the eastern hemisphere, he 

 will, it is believed, recognize that this is essentially one region, the higher 

 portions of which have been iiflected by similar causes, and, as it would seem 

 natural to suppose in the absence of evidence to the contrary, at about the 

 same time. 



In point of fact the region in question may be separated into two divisions 

 of importance, one of which, however, is of much greater extent than the 

 other. Tiiis latter division includes the Scandinavian Range and the reirions 

 adjacent to it, extending into Russia on the east and southeast, covering 

 North Germany on the south and a part of the British Islands on the south- 

 west. The other region is that of the Alps, with which may be included the 

 Pyrenees on the west and the Caucasus on the east. 



Northeastern North America, as a field of former glaciation, includes an 

 area the limits of which can be but imperfectly defined, for reasons which 

 will be set forth with some detail farther on in the present section. Roughly 

 speaking, it embraces New England, New York, the region of the Great Lakes, 

 and an indefinite portion of the adjacent British Provinces. Of its extent 

 towards the north nothing is definitely known. 



In pursuing our present inquiry we have, in the first place, to set forth 

 the facts on which is based the statement just made that the only phenom- 

 ena involving really difficult problems of past glaciation with which we have 

 to deal are limited in their occurrence to areas of moderate dimensions as 

 compared with the entire land surface of the globe, and situated as defined 

 above. That is to say. the former presence of ice and snow in regions 

 where they no longer exist was a local matter, and not one in which all the 

 continental masses were concerned. 



