ABSTRACT. 21 



Chapter XII. Outline of glacial and postglacial history of the Great Lakes 

 region. — A brief outline, of the Great Lakes history during and after the recession of the last 

 ice sheet is given. 



Chapter XIII. Glacial Lake Maumee. — Glacial Lake Maumee, the oldest of the glacial 

 lakes in the Huron-Erie basin, is said to have enlarged and contracted in area with the reces- 

 sion and readvance of the ice border and to have shifted its outlet from Fort Wayne, Ind., to 

 Irulay, Mich. The beaches of the south shore are described as having been apparently greatly 

 disturbed by winter ice that grounded and shoved the shore material into ramparts back of 

 the original shore line. Ice attraction is also briefly discussed. 



Chapter XIV. Glacial Lake Chicago. — The three beaches of the southern part of the 

 eastern shore of Lake Michigan, formed by a lake discharging southwestward to the Illinois 

 River, are briefly described. 



Chapter XV. Glacial Lake Saginaw. — A lake formed in the Saginaw basin outside 

 the oscillating ice border is said to have varied considerably in area and yet to have discharged 

 southwestward continuously through the Grand River outlet to Lake Chicago. 



Chapter XVI. Glacial Lake Arkona. — A lake that covered much of the area of Lake 

 Maumee and Lake Saginaw and discharged into the Grand River outlet is described. 



Chapter XVII.. Glacial Lake Whittlesey. — Lake Arkona is interpreted as having been 

 so encroached on by a readvance of the ice border on the "Thumb" of Michigan that it was 

 separated into two bodies of water, that to the east being called Lake Whittlesey and that to 

 the west the Second Lake Saginaw ; Lake Whittlesey discharged by the Ubly outlet to the Second 

 Lake Saginaw and thence to the Grand River outlet and Lake Chicago. 



Chapter XVIII. Glacial Lake Wayne. — The ice border is described as having receded 

 sufficiently after its readvance to the main moraine of the Port Huron system to permit east- 

 ward discharge past Syracuse, N. Y., when the lake was drawn down to the level of the Wayne 

 beach of southeastern Michigan. 



Chapter XIX. Glacial Lake Warren. — The outlets of Lake Wayne past Syracuse are 

 interpreted as having been covered by a readvance of the ice by which the glacial lake was 

 raised high enough to discharge westward through the Grand River outlet, though at a level 

 slightly below that of Lake Arkona. The name Lake Warren is applied to this expanded body 

 of water. 



Chapter XX. Glacial Lake Ltjndy and the transition to Lake Algonquin. — With 

 the recession of the ice border, discharge eastward is said to have been resumed, probably at 

 first by way of the Syracuse channels. But later, by the opening of the Mohawk Valley through 

 ice recession, the lake was drawn down to the level of the Niagara escarpment in the Erie basin 

 and still lower in the Ontario basin. Niagara Falls then came into operation, and the Erie 

 basin held a small lake which received the discharge from a glacial lake in the southern part 

 of the Huron basin, the Early Lake Algonquin. Lake Chicago still persisted as an independent 

 lake in the Michigan basin and Lake Duluth in the Superior basin. 



Chapter XXI. Glacial Lake Algonquin. — By the opening of the low passage from the 

 Michigan to the Huron basin Lake Chicago is interpreted as having become confluent with the 

 Early Lake Algonquin. With further recession of the ice the Superior waters were also admitted 

 and the great glacial Lake Algonquin resulted. By the uncovering of the Trent Valley in 

 Ontario the discharge through the St. Clair Valley was abandoned, the Trent being the lower. 

 Eventually differential uplift carried the Trent outlet above the level of the St. Clair, and the 

 discharge returned to the St. Clair outlet and remained there during much of the time of rapid 

 differential uplift. In connection with Lake Algonquin the contemporary lakes in the St. 

 Clair and Erie basins are briefly treated. 



Chapter XXII. The Nipissing Great Lakes. — The withdrawal of the ice is described as 

 having opened the low passage to the Ottawa Valley. Eastward discharge along the south 

 slope probably began while the ice was still present in the valley. The Nipissing Great Lakes 

 stage dated from the complete opening of this valley and continued to the time when northward 



