MOKAINIC SYSTEMS AT HEADS OF LAKE MICHIGAN AND SAGINAW BASINS. 201 



GLACIAL DRAINAGE. 



The glacial drainage of the interlobate district is a matter of some interest as it departs 

 considerably from the present lines. It was governed by the bordering ice lobes and only to a 

 slight extent by the slopes of the land surface. 



When the ice border stood at Hanover in southern Jackson County the water from the 

 reentrant angle followed South Fork of Kalamazoo River to the bend near Homer in southeastern 

 Calhoun County, where it cut across the narrow space that now separates the St. Joseph and 

 Kalamazoo valleys and entered the St. Joseph Valley. It followed this valley to the great bend 

 at South Bend, Ind., where it passed into the headwater part of Kankakee River and thence 

 to Illinois and Mississippi rivers and the Gulf of Mexico. 



When the ice border stood on the north and east sides of Grass Lake Plain in eastern Jackson 

 and western Washtenaw counties the drainage was not northward from Jackson down Grand 

 River but was westward through a series of swampy channels that led across to the Kalamazoo 

 through western Jackson County. It seems to have followed the present course of the Kalamazoo 

 about to the site of the city of Kalamazoo and thence went southward to the St. Joseph Valley 

 near Three Rivers and on to the Kankakee past the site of South Bend. 



When the ice border stood near Milford the drainage followed down Huron River about 

 to Portage Lake. From there it continued westward to the Portage Swamp in northwestern 

 Jackson County and thence to the Grand River valley just north of Jackson. After following 

 Grand River to Eaton Rapids it passed westward, as shown on the Lansing topographic sheet, 

 through a swamp now utilized by the Michigan Central Radroad to Charlotte, where it entered 

 Battle Creek. Thence it passed to the Kalamazoo and apparently followed the course of the 

 present river to the site of Plainwell, a few miles below Kalamazoo. From there it seems to have 

 passed southwestward for a time through the low district west of the Kalamazoo morainic 

 system to the head of the Kankakee at South Bend, a part of its course being through long 

 pools or lakes. 



With the northward recession of the Saginaw ice lobe the drainage continued down Grand 

 River a few miles beyond Eaton Rapids and then, as shown on the Lansing topographic sheet, 

 passed westward to the Thornapple, which it followed to the bend below Hastings. Thence it 

 passed southward by Gun Lake and down the Gun River valley to the Kalamazoo. It seems 

 to have passed directly across the Kalamazoo Valley and to have reached the headwaters of 

 Paw Paw River in northeastern Van Buren County. Thence it seems to have followed down 

 the Paw Paw Valley to a glacial lake, the incipient Lake Chicago, that filled the lower course 

 of the Paw Paw and St. Joseph valleys at the time when the Lake Michigan lobe extended but 

 little beyond the limits of the present lake. From this small glacial lake the drainage led along 

 the border of the ice to the south end of the Lake Michigan basin (see pp. 226-227) and thence into 

 Desplaines, Illinois, and Mississippi rivers. It is not entirely certain that the drainage from the 

 headwater part of the Huron took this course through the Thornapple Valley; it may have 

 followed the course past Ann Arbor next to be considered. 



When the Huron-Erie ice lobe had receded southeastward to the site of Ann Arbor the 

 glacial drainage followed down the Huron Valley, with perhaps a slight deflection south of the 

 valley near Dexter. On reaching the edge of the ice sheet near Ann Arbor it turned south- 

 westward through a large swampy valley (see Ann Arbor folio and topographic sheet) that 

 passes just north of Pittsfield Junction and Saline to the Raisin Valley, in southwestern Wash- 

 tenaw County. Thence it followed down the Raisin Valley to the vicinity of Adrian, where it 

 entered Lake Maumee, whose outlet led past Fort Wayne, Ind., to the Wabash. 



TILL PLAINS. 



Among the morainic ridges of the Huron-Erie lobe in Oakland, Washtenaw, Lenawee, and 

 Hillsdale counties narrow strips of till plain have surfaces much smoother than those of the neigh- 

 boring ridges. The till plains are not continuous, however, for many mdes, being broken by the 

 interlocking ridges. Near the State line of Michigan and Ohio the ridges become more widely 



