FOREIGN 535 



along the ice-front from western New York to the site of Chicago, 

 where was the outlet to the Mississippi. This body of water 

 occupied parts of the basins of the present Lakes Ontario, Erie, 

 Huron, and Michigan. When the continued retreat of the ice 

 had freed the basin of Lake Ontario, the outlet is believed to have 

 shifted to a low point near Rome (N.Y.)and to have discharged 

 into the Mohawk River, a change which lowered the water-level 

 by several hundred feet. The shallowed waters were no longer 

 sufficient to cover the divides between the distinct lake basins, and 

 three lakes were formed, — Lake Huron, still partly walled by ice, 

 Lake Erie, and Lake Iroquois, which occupied the Ontario basin, 

 but was larger and emptied into the Mohawk, for the St. Lawrence 

 channel was still blocked by the ice-front. 



None of these lakes had the size and position of their modern 

 representatives. A gentle upheaval of the region, rising toward 

 the northeast, shifted all the lakes to the southwest. Lake Huron, 

 which had previously discharged its waters (it is believed by some 

 authorities) by way of the Ottawa River, thus was given an outlet 

 through the St. Clair River and became joined to Lake Erie, 

 which thus received the overflow from the upper lakes. The 

 complete removal of the ice, together with the diastrophic move- 

 ments, gave to Lake Ontario its present size and shape and opened 

 to it an outlet into the St. Lawrence. 



The Pleistocene was closed and the Recent epoch inaugurated 

 by a movement of upheaval which raised the continent to its 

 present height. 



Foreign Pleistocene 



The Glacial epoch in Europe ran a course remarkably parallel 

 with its history in North America. After the first Glacial and 

 Interglacial stages (perhaps representing the Albertan and Afto- 

 nian), came the time of the greatest expansion of the ice, the 

 Saxonian stage of Geikie, which is believed to correspond to the 

 Kansan of America. The great centre of dispersion was the Scan- 

 dinavian peninsula, where the ice was probably 6000 to 7000 feet 

 thick, and whence it flowed outward, filling the Baltic and North 



