LATER MORAINES OF LAKE MICHIGAN, SAGINAW, AND HURON-EBIE LOBES. 227 



between the two ridges in southern Berrien County and the neighboring part of Laporte County, 

 Ind., but does not appear to have been markedly lowered. 



Lake on Trail Creek. — From the south end of the pool on Galien River the waters passed 

 across a low divide to a pool in the lower course of the two forks of Trail Creek east and south 

 of Michigan City, Ind., and from this pool to Little Calumet River, and thence into a small lake 

 that extended from near Chesterton, Ind., to the Chicago outlet. The drainage from the 

 lake on the St. Joseph descended only 20 feet to the Calumet Valley near Chesterton, and this 

 descent was apparently made in the short passages from one pool to another. Sand is found 

 along much of the course of this drainage but is perhaps in part due to deposition from the 

 receding ice sheet as it melted back from the Valparaiso to the Lake Border morainic system; 

 some of it, however, was probably deposited by this drainage. 



Incipient Lake Chicago. — The lake at the south end of the Lake Michigan basin should, 

 perhaps, be termed the incipient Lake Chicago, for it developed into that lake and had the 

 same level and the same outlet. Its level was about 60 feet above Lake Michigan, or 640 feet 

 above tide. As its southern limits are the same as those of the highest or Glenwood stage of 

 Lake Chicago, the description of the border of the Glenwood beach given in Monograph XXXVIII 

 applies to the border of this lake from near Chesterton to the Chicago outlet; the smaller lake, 

 however, probably contributed but a small part of the beach material of this highest stage of 

 Lake Chicago. This small lake expanded northward as the ice receded; in the early days of 

 the Lake Border morainic system it stood entirely outside the limits of Lake Michigan, but by 

 the time the till ridge south of Holland had been formed it probably extended some miles 

 over the bed of the southern end of Lake Michigan. A considerable part of the district occupied 

 by this lake is coated heavily with sand and sandy gravel, much of which seems referable to 

 currents in the later and more expanded lake, but some of which may have been deposited 

 earlier, during the recession of the ice from the Valparaiso to the Lake Border morainic system. 



Wisconsin and Illinois drainage. — In southern Wisconsin and northern Illinois the lines 

 of glacial drainage are traceable on the topographic maps from Milwaukee southward to Des 

 Plaines River and to the Chicago outlet. There appears, therefore, to have been no marked 

 ponding of the waters along the ice front on the Wisconsin side of the Lake Michigan basin. 



LATE GLACIAL DRAINAGE. 



In the later stages of the development of the Lake Border morainic system considerable 

 ponding took place farther north than the Kalamazoo Valley and was apparently maintained 

 until the ice border had receded from the morainic ridges near Holland sufficiently to allow 

 free communication west of them to the somewhat expanded Lake Chicago. During the occu- 

 pancy and development of the portion of Covert Ridge north of Kalamazoo River, the drainage 

 apparently made its way by streams and small lakes into the glacial lake on the Kalamazoo. 

 But when the ice border had receded to the westernmost of the till ridges in Ottawa County 

 the water apparently found its way along the ice border to the vicinity of Holland and there 

 entered Lake Chicago. 



At one time during the recession of the ice border the Muskegon, which received drainage 

 from the Lake Michigan lobe on the west and from the Saginaw Bay lobe on the east, ran south- 

 ward past Rice Lake in southeastern Newaygo County, its altitude near Rice Lake being about 

 800 feet above sea level. It followed Rouge River to its junction with Grand River near Grand 

 Rapids and probably continued southward (for a time at least), leaving the Grand River valley 

 at the south edge of Grand Rapids and traversing a valley which leads past Ross to Rabbit 

 River and thence into the lake in the lower part of the Kalamazoo. The altitude of the aban- 

 doned valley that runs south from Grand Rapids, as shown by the Grand Rapids topographic 

 sheet, is somewhat less than 700 feet, or fully 100 feet below the channel in Newaygo County, 

 where the Muskegon waters passed Rice Lake into the Grand River drainage. There probably 

 was some ponding of waters along the Rouge Valley, but the valley is comparatively narrow 

 and the ponded water would be considered a river pool rather than a lake. 



