CHAPTER X. 



LATER MORAINES OF THE LAKE MICHIGAN, SAGINAW, AND HURON-ERIE 



LOBES. 



LAKE BORDER MORAINIC SYSTEM OF LAKE MICHIGAN LOBE. 



By Frank Leverett. 



COURSE AND DISTRIBUTION. 



A complex group of moraines closely bordering the southern end of Lake Michigan was 

 discussed in Monograph XXXVIII under the name Lake Border morainic system. This system 

 has now been traced northward along the eastern side of the Lake Michigan basin, across the 

 highlands between the northern j:>art of Lake Michigan and Saginaw Bay, around the circuit 

 of the Saginaw Basin to the " thumb " of Michigan, and southward through southeastern Michigan 

 along the eastern slope of the "thumb." In places, however, it is so intricately combined with 

 earlier and later systems that its differentiation is not complete. The individual moraines 

 of this system are still more difficult to trace around this entire circuit, for in some places they 

 are bunched together and in others they are interrupted by gaps of considerable width. 



Only in the southern part of the Lake Michigan basin is the Lake Border the innermost 

 system; in the northern part later moraines which do not extend so far to the south lie within it. 

 As far north as Holland the Lake Border system lies close to the shore of Lake Michigan, but 

 from Holland northward to Oceana County it is 15 to 25 miles back from the shore. In Oceana 

 County it returns to the shore and forms the prominent "clay banks" in the southwestern part 

 of the county. From the vicinity of Hart northward it bears inland and is shut off from the 

 lake by later moraines. It wraps around the northern part of the great interlobate moraine 

 between the Lake Michigan and Saginaw lobes (see PI. VII) and a little north of Cadillac 

 bears away eastward. Within a short distance its southern or outer members turn southeast 

 into the Saginaw basin, but its later members make longer circuits and run nearly to Lake 

 Huron before doubling to the south. In Newaygo and Lake counties the Lake Border system 

 banks against the earlier interlobate moraine to the east, but in Wexford and Missaukee counties 

 it is quite distinct from the interlobate, and it remains so in its course southward along the 

 west side of the Saginaw basin. 



TOPOGRAPHY. 



ALTITUDE. 



The outer members of the Lake Border morainic system reach their greatest height 

 immediately north and west of Cadillac, where they attain an altitude of 1,500 feet above sea 

 level. The outermost ridge for 20 miles west from the line of Missaukee and Wexford counties 

 stands above 1,400 feet. Beyond the turn to the south the ridge gradually declines in altitude, 

 but a considerable portion of it is above 1,100 feet as far south as the latitude of Big Rapids 

 and some points on it are above 1,300 feet as far south as the latitude of Baldwin. The ridges 

 south of Muskegon River are scarcely 800 feet in altitude, the descent being very rapid from the 

 great morainic mass north of Muskegon River to the slender moraines that lead away to the 

 south. The decline becomes more gradual as the head of Lake Michigan is approached, but 

 from the vicinity of South Haven southward to the head of the lake the ridges stand less than 

 700 feet above sea level. 

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