MOEAINIC SYSTEMS AT HEADS OF LAKE MICHIGAN" AND SAGINAW BASINS. 189 



From the reentrant angle a few miles south of Big Rapids the drainage appears to have 

 passed southward from the Muskegon Valley to the head of the Eouge River valley and thence 

 to Grand River, beyond which it probably followed the course past Ross previously outlined. 

 As the ice lobes separated this line of glacial drainage extended up the Muskegon Valley as far 

 probably as the vicinity of Hersey. There appears also to have been some drainage from the 

 Lake Michigan lobe down Hersey River to Hersey. The portion of the Muskegon above Hersey 

 served as a line of glacial drainage until the ice sheet had receded east of the headwaters of the 

 river, or until later than the development of the morainic system under discussion. 



KALAMAZOO MORAINIC SYSTEM OF THE SAGINAW LOBE. 



COURSE AND DISTRIBUTION. 



The Kalamazoo morainic system of the Saginaw lobe connects at the west with the Kala- 

 mazoo morainic system of the Lake Michigan lobe and appears to be its full correlative. Its 

 outer or southern border is definitely limited by a large outwash apron along much of its course, 

 the only exception being a few miles in western Jackson County, where it terminates in a hilly 

 district through which lines of border drainage were developed. The border trends southeast- 

 ward from Prairieville in southwestern Barry County across the northern part of Calhoun 

 County into western Jackson County. Near the village of Spring Arbor, about 10 miles west of 

 Jackson, it swings to north of east and runs past Jackson to the edge of Washtenaw County, 

 where it connects with the correlative system (Mississinawa morainic system) of the Huron- 

 Erie lobe. The belt is only about 2 miles wide east of Jackson and for a few miles in the vicinity 

 of Marshall, but elsewhere is 6 to 12 miles wide. At its western end it occupies the entire space 

 between Prairieville and Hastings, its north border in the vicinity of Hastings being Thornapple 

 River valley. It is also of great breadth along the east side of Battle Creek, where a spur 

 extends from it northward nearly to Charlotte. In northwestern Jackson County it is separ- 

 able into three more or less distinct moraines with intervening narrow strips of gravel plain and 

 border drainage. The inner members of the system, however, die out or become very diffuse 

 east of Grand River. 



TOPOGRAPHY. 



ALTITUDE. 



The relief of this morainic belt above the gravel plain on its outer border is but slight, in 

 most places being less than 30 feet and in few more than 50 feet. The gravel plain, however, 

 is elevated, the altitude hi the reentrant angle between the Lake Michigan and Saginaw lobes 

 being nearly 1,000 feet and in that between the Saginaw and Huron-Erie lobes more than 1,000 

 feet above sea level. The border drainage lines leading westward from Jackson are also between 

 950 and 1,000 feet above sea level. The lowest part of the border is in the vicinity of Battle 

 Creek, where the gravel plain is scarcely 900 feet and the moraine only about 950 feet. The 

 moraine is traversed by several streams, such as Wabascon, Wanandager, and Battle creeks, 

 but these streams run in deep depressions whose borders are higher than the plains in which 

 the streams have their sources. 



RELIEF. 



The inner border relief is inconspicuous in Eaton and Barry counties, there being in places 

 a gradual transition from the moraine to the bordering till plains. In northeastern Calhoun 

 County a large swamp lies immediately north of the moraine, but its altitude is only 25 to 50 

 feet below the bordering morainic ridges. The moraine leading northeastward from Jackson 

 rises nearly 150 feet above the Portage swamp which lies on its north border, this being the most 

 prominent part of the entire morainic system. The relief of the ridges in northwestern Jackson 

 County above the depressions occupied by Grand River and Sandstone Creek in places exceeds 

 100 feet. 



