MOKAINIC SYSTEMS AT HEADS OF LAKE MICHIGAN AND SAGINAW BASINS. 207 



OUTER BORDER DRAINAGE. 



At the time the Charlotte niorainic system was forming the drainage appears to have been 

 westward from the interlobate tract in Oakland Comity through a chain of swamps and partly 

 gravel filled valleys along or near the outer border of the system as far as Charlotte and thence 

 down Battle Creek to the Kalamazoo. The drainage left Huron River near the bend at the 

 line of Livingston and Washtenaw counties and passed westward by Pinckney and Anderson 

 and Unadilla to northeastern Jackson County into the Portage Swamp, which emptied into 

 Grand River a short distance north of Jackson. It followed the general course of Grand River 

 valley to a point immediately east of Eaton Rapids, though it was perhaps deflected northward 

 for a short distance through a sandy tract known as the Montgomery Plains, for the present 

 river immediately south of this sandy tract flows in a very narrow valley which does not 

 appear to have carried the glacial drainage and which was probably occupied by stagnant ice. 

 Beyond Eaton Rapids the ice still blocked the channel, and the glacial waters (see Lansing 

 topographic sheet) flowed westward through the swamp traversed by the Michigan Central 

 Railroad between Eaton Rapids and Charlotte. Numerous tributary lines of glacial drainage 

 led southward from the edge of the Charlotte morainic system in Livingston and Ingham 

 counties to join this main line of drainage. 



The glacial drainage seems to have had a good gradient only in Oakland County, for in south- 

 ern Livingston, northwestern Washtenaw, northeastern Jackson, southwestern Ingham, and 

 southern Eaton counties there is scarcely any descent. The altitude of the gravel plain in 

 southern Livingston County is between 900 and 920 feet, much of it being less than 910 feet. 

 That of the Portage Swarhp in northeastern Jackson County appears also to be fully 900 feet. 

 That of the Montgomery Plains east of Eaton Rapids, where the glacial drainage seems to 

 have made a detour to the north of the Grand River valley, is above 900 feet and that of the 

 swamp between Eaton Rapids and Charlotte is 900 to 903 feet in its western portion, as shown 

 by the Lansing topographic sheet. In passing down Battle Creek very little descent seems to 

 have been made in the first 10 miles, there being a channel marking an old detour of the glacial 

 drainage to the west of the present stream past Olivet station, whose floor is 885 to 890 feet. 

 Rapid descent begins south of Olivet station, the channel floor being 870 feet at Bellevue and 

 about 825 feet at the city of Battle Creek, 12 miles below Bellevue. The distance having a 

 very low gradient is about 75 miles, and the amount of fall is scarcely 20 feet. It is probable, 

 therefore, that the waters were ponded, but were in sufficient volume to give a strong current 

 through to the lower portion of Battle Creek. With the exception of the Portage marsh in 

 northeastern Jackson Comity, where the water may have spread out to a width of 3 or 4 miles, 

 the topography is such as to indicate that the width generally throughout this 75 miles of 

 ponded drainage was scarcely more than a mile, and in places it must have been reduced to less 

 than one-half mile. The course of the glacial drainage just outlined could not have been different 

 under the conditions of altitude that obtained in the region while the ice was filling the portion 

 of the Grand River valley below Eaton Rapids. To have passed through any of the channels 

 utilized during the development of the Kalamazoo morainic system the waters would have been 

 compelled to rise to about 960 feet. 



From the city of Battle Creek the glacial drainage followed down the Kalamazoo Valley to 

 the vicinity of Plainwell, descending from. 825 feet to 750 feet in about 35 miles. Thence the 

 drainage took a southwestward course through the low plain west of the Kalamazoo morahiic 

 system, descending to about 725 feet in the vicinity of Dowagiac. There a narrow lake (Lake 

 Dowagiac) seems to have extended from Dowagiac to South Bend, Ind., from which the dis- 

 charge was southwestward along the Kankakee to Illinois and Mississippi rivers and the Gulf 

 of Mexico. 



From the portion of the border of the Charlotte morainic system west from the meridian of 

 Charlotte the drainage was inconspicuous to the vicinity of Hastings, but from that city up to 

 the reentrant angle near Dias Hill in southern Kent County it was large, producing a broad 

 outwash apron whose altitude in the reentrant angle between the Saginaw and Lake Michigan 



