GLACIAL LAKE MAUMEE. 349 



Glacial Lake Lapeer, a small lake in central Lapeer County, existed during the building of 

 the Defiance moraine. Silverwood glacial lake, in northern Lapeer County, appears to have been 

 formed at the time of the Imlay or perhaps of the Goodland moraine. It stood at about 860 feet 

 altitude near Silverwood and received the Silverwood and Fostoria outwash aprons. It may be 

 that a closing of the outlet in Genesee County by the readvance to either the St. Johns or the 

 Fowler moraine held it in place. Its relations and correlative moraines, however, are not 

 definitely known. 



During the remainder of the life of Lake Maumee, while the Goodland, Berville, Mount 

 Clemens, Emmett, and Yale moraines were being made, the oscillations went on without affecting 

 the level of the lake so far as known. Perhaps at the retreat following the Yale moraine a new 

 outlet, through the East Dayton channel, may have been opened just before the final fall of the 

 waters to a much lower level; but the relations and connections of this channel are also still 

 problematic. 



ICE BARRIERS OF LAKE MAUMEE. 



In its earliest beginnings Lake Maumee was confined to a small area in Indiana and north- 

 western Ohio and its ice barrier was then the front of the Huron-Erie or Maumee ice lobe. The 

 subordinate members of the Fort Wayne moraine are faintly developed between the main Fort 

 Wayne and Defiance moraines, but there are several of them and they mark as many resting places 

 of the ice barrier, each probably marking the culmination of a slight readvance. During the time 

 of the Defiance and Birmingham moraines the Fort Wayne outlet was still active and the relation 

 of the ice barrier to the lake continued to be extremely simple. But when the oscillations 

 opened outlets on the '''thumb " and closed them by readvances the level of the lake was probably 

 affected by nearly every movement of the ice front. 



Until the ice had retreated about to the Mount Clemens moraine the ice barrier presented a 

 single lobate front, for the Huron and Erie ice lobes were probably still welded together along 

 their line of contact in southwestern Ontario. The crease between them, however, had become 

 accentuated. Ontario Island, 1 which had probably begun to be uncovered at the time of the 

 Defiance moraine, had now become much enlarged and the ice lobes were on the point of complete 

 and final separation. The position of the moraines in Michigan and southwestern Ontario seems 

 to indicate that the separation occurred just after the building of the Mount Clemens moraine. 



During the closing stages of Lake Maumee the ice front stood on the Yale moraine or possibly 

 somewhat farther north, and the correlative of this in the Lake Erie basin is probably found in 

 one of the moraines immediately preceding the Gowanda moraine of western New York. This 

 is in harmony with the correlation of certain gravel deposits at Girard and Fairview, Pa., with 

 the lowest beach of Lake Maumee, and it is also in harmony with the very clear correlation of the 

 Alden moraine of western New York with a late substage of the Port Huron morainic system of 

 Michigan. Three positions of the western barrier of Lake Maumee are shown in figure 6 (p. 370). 



At its close, therefore, Lake Maumee, like all the later Huron-Erie glacial lakes, was retained 

 by two separated ice barriers, one in the Huron basin and the other in the Erie basin. At this 

 time Lake Maumee had a short stretch of northern land shore in the vicinity of London, Ontario. 

 The length of this, however, could not have been great, and it endured for only a relatively short 

 time before the lake waters fell to a lower level. A faint shore line marking this last stage of 

 Lake Maumee may be looked for in the vicinity of London, though none has yet been reported. 



CORRELATIVES OP LAKE MAUMEE. 



As nearly as can be determined by a study of correlative moraines in the different lake 

 basins, it seems almost certain that Lake Chicago had its early beginnings at about the same 

 time as Lake Maumee, but such evidence as is now available indicates that Lake Duluth, in the 

 western end of the Lake Superior basin, began later. Toward the close of the existence of Lake 

 Maumee Lake Saginaw was formed in front of the Saginaw lobe. It received the overflow of 

 Lake Maumee but did not attain large size at this time. 



As the waters fell to the level of the Arkona beaches a transient precursor of Lake Whittlesey 

 must have been formed, but its duration was probably very briefs 



1 The uncovering of Ontario Island is described by the writer in The moraine systems of southwestern Ontario: Trans. Canadian Inst., vol. 10, 

 1913, pp. 37-39, with map. 



