340 THE ILLINOIS GLACIAL LOBE. 



20 miles. It is narrowest just south of the Michigan and Indiana State 

 line arid broadest in the vicinity of the Indiana and Illinois State line. 

 The glacial map (PL VI) sets forth its variations in width. 



In northern Illinois this morainic system becomes merged with older 

 moraines in the composite belt already discussed, but it evidently finds its 

 continuation northward along the inner or eastern border of that belt as far 

 as the peninsula between Green Bay and Lake Michigan. 



The Valparaiso morainic system in Michigan is made to include the 

 entire bulky morainic belt of Lake Michigan drift, from the Grand River 

 Valley southward, though it consists in places of two or more constituent 

 ridges. These ridges coalesce and separate by turns, but nowhere become 

 so distinctly separated as to appear to merit individual names and separate 

 descriptions. This belt of Lake Michigan drift is distinct from moraines of 

 the Saginaw lobe in Berrien and southern Van Buren counties, but in 

 northern Van Buren County it becomes so closely associated with the 

 Saginaw moraines that the line of separation can be made out only upon 

 close study. The moraines remain closely associated from Van Buren 

 County northward at least as far as Grand Rapids, beyond which the writer 

 has not carried his investigations. Investigations by the Michigan survey 

 indicate that later moraines may conceal it 'in the northern part of the 

 Southern Peninsula. 



BORDER BETWEEN THE LAKE MICHIGAN AND SAGINAW BAY LOBES. 



The nature of the border line between this morainic system and the 

 neighboring morainic system of the Saginaw lobe merits special attention. 

 The description begins in southern Allegan County and is carried southward 

 to northern Indiana. 



The eastern border of the Valparaiso system, as shown in PL XV, is 

 apparently found in the eastern tier of townships in Allegan County from 

 the northeast corner of the county southward to the vicinity of Monteith. 

 The moraine here has an overwash gravel plain along its eastern border 

 occupying the western half of Martin and central part of Wayland town- 

 ships. This plain shows a perceptible eastward slope away from the moraine. 

 Along its east border there is a moraine of the Saginaw lobe. This moraine 

 swings westward just south of Monteith and the two ice lobes appear to 

 have come into close contact for a few miles south from that point. The 

 Saginaw movement was sufficiently strong, not only to meet the ice lobe on 



