MORAINIC SYSTEMS AT HEADS OF LAKE MICHIGAN AND SAGINAW BASINS. 179 



two east from the moraine they drop 25 to 30 feet and within a few miles they drop 50 to 75 

 feet. The water probably ran down the slope eastward and southeastward directly away from 

 the moraine until it met the trunk stream flowing southward from the reentrant angle between 

 the ice lobes. This stream apparently passed east of the site of the city of Kalamazoo and 

 continued southward past Vicksburg, reaching the St. Joseph Valley between Mendon and 

 Three Rivers. The southward slope of the portion of the plain traversed by the trunk stream 

 is indicated by the drainage, streams tributary to the St. Joseph having their sources on the 

 immediate border of the Kalamazoo Valley, and is demonstrated by the following list of 

 elevations: 



Elevations on plain leading from reentrant angle. 



Feet. 



Prairieville 1, 000 



Milo 957 



Richland 928 



North bluff of Kalamazoo 880 



South bluff of Kalamazoo. . '. 875 



Vicksburg 857 



Moore Park 841 



A definite bluff 15 to 50 feet high on the eastern side of the gravel plain from Kalamazoo 

 River southward to St. Joseph River puts this border in decided contrast to the western bor- 

 der, which grades upward into the moraine. Possibly this bluff was cut by border drainage 

 before the ice had receded to the position of the outer ridge of the Kalamazoo morainic system, 

 for the wide extent of plain over which the waters were free to flow after the ice had receded 

 to that system would seem to leave no necessity for the stream to crowd its eastern bluff. The 

 altitude of the plain for several miles west from this eastern bluff seems also to correspond 

 closely to that of the base of the bluff, so that no reason for crowding is to be found in the 

 slope of the eastern portion of the plain. 



BASINS AND CHANNELS. 



Basins are very numerous on this outwash tract on the immediate border of the outer 

 ridge of the Kalamazoo morainic system but are scarce out in the midst of the plain; most of 

 them are large, an area of a square mile or more being not uncommon. North of Kalamazoo 

 River they are numerous both on the border of the ridge andin the plain. Their wide distribution 

 is somewhat surprising and seems to indicate that the development of the Kalamazoo system 

 followed closely on the recession of the ice border, there being insufficient time for the large 

 detached masses of ice left in the course of the recession to become entirely melted before the 

 filling of outwash from the Kalamazoo system was completed. 



In the vicinity of Kalamazoo several conspicuous valley-like depressions lead from the border 

 of the system eastward to the Kalamazoo Valley. They are about 50 feet below the neighboring 

 parts of the gravel plain and are one-eighth to one-fourth mile in width. At the western or 

 morainal end they head very abruptly, as if cut by a waterfall. Their beds are not graded to a 

 uniform slope but contain basins and other inequalities, which, however, may be no greater than 

 would result from the rush of a strong current of water. One valley is followed by the main fine 

 of the Michigan Central Railroad for about 2 miles from the western part of the city of Kalama- 

 zoo. Others lie both to the north and to the south. The longest heads in Crooked Lake in 

 sec. 15, Texas Township, about 10 miles southwest of Kalamazoo, leads northeastward, and opens 

 immediately south of the city into a part of the gravel plain corresponding hi elevation with its 

 bed. These valley-like depressions are thought to indicate that the discharge from the ice 

 border became localized on certain lines toward the close of the development of the moraine 

 and began to cut instead of fill. While the waters were issuing in shallow sheets all along the 

 edge of the ice they would naturally lay down their earthy burden promptly and would aggrade 

 the region, but they could hardly do this when they flowed along restricted lines, especially if 

 in considerable volume. This feature is met with in gravel plains elsewhere, though it is by no 

 means common. 



