292 PLEISTOCENE OP INDIANA AND MICHIGAN. 



DETROIT INTERLOBATE MORAINE IN SOUTHWESTERN ONTARIO. 



On account of its intimate bearing upon the relations of the Huron and Erie ice lobes 

 during the time of their shrinkage and separation the following facts are given relating to the 

 moraines in the region east of Detroit River, chiefly in Essex, Kent, and Elgin counties, Ontario. 

 The Detroit interlobate moraine runs southeast in a direct line from Detroit to the high ground 

 a mile or two northwest of Leamington. It carries the Talbot road on its broad crest for a 

 large part of the distance, and from Essex to 2 miles southeast of Cottam it carries also a finely 

 formed gravelly bar of the Grassmere beach. From Leamington its probable continuation 

 runs as a low, flat divide northeast to the county line and then east to Port Alma, where it 

 forms a high bluff on the lake shore. To the east, after an interval of about 12 miles in which 

 it has been cut away by the present lake, it reappears 5 miles southwest of Blenheim in a 

 bluff 80 feet high as a more distinct morainic ridge, with beaches on its crest and flanks. From 

 the lake shore it runs northeast through Blenheim and passes about 2 miles southeast of Ridge- 

 town. A mile or two east of Port Alma small drainage courses, which formerly headed south 

 of the bluff, show clearly the former existence of higher ground in that direction. From the 

 trend of the ridge at both points on the bluff and from the decapitated stream beds it seems 

 certain that part of this higher ground, now cut away by the waves, was at least 1 or 2 miles 

 out from the present shore. 



So far as can be judged on present information this ridge is continuous with the Detroit 

 interlobate moraine and is interlobate in character throughout. It seems to have been begun 

 at the time of the Birmingham moraine and probably represents several later subordinate 

 halts of the ice front. If this ridge is interlobate it shows that at the time of its formation 

 the Huron lobe was crowding the Erie lobe to the south and was even pressing slightly over 

 into the space now occupied by Lake Erie. (See PI. V, p. 62; also fig. 13, p. 485.) At earlier 

 stages of the ice recession the interlobate line probably extended more directly southwest from 

 Leamington; during the building of the Defiance moraine it probably terminated at the sand 

 deposit in Fulton County, Ohio. 



