GLACIAL FORMATIONS AND DRAINAGE FEATURES OF 

 THE ERIE AND OHIO BASINS. 



By Frank Leverett. 



CHAPTER L 

 INTRODUCTION. 



OUTLINE OF THE AREA AND SUBJECTS DISCUSSED. 



The region embraced in this discussion has for its nortliern boundary 

 the south hue of Michigan and the southern borders of Lakes Erie and 

 Ontario; for its eastern boundary the Grenesee River; for its southeastern 

 and soutliern boundary the Allegheny and Ohio rivers, except in northern 

 Kentucky, where the southern limits of the drift extend beyond the Ohio 

 River ; and for its western boundary the driftless part of southern Indiana. 



There is included at the east a system of interlobate moraines lying 

 between the lobe of the Finger Lakes region in New York and the Grand 

 River lobe of northeastern Ohio and the neighboring parts of Pennsylvania 

 and New York, but no discussion of the moi'aines of the Finger Lakes 

 region is attempted. The deposits and features of the region covered by 

 three glacial lobes of Wisconsin age are described — the Grand River, the 

 Scioto, and the Miami — with the interlobate tracts between, and the valley 

 gravels leading away from these lobes. The older drift lying outside 

 and also beneath the Wisconsin deposits, and the silt deposits which cover 

 this older drift, are also described. In addition to this an attempt is made 

 to interpret some of the drainage features of the region. There is also a 

 discussion of a part of the lake history succeeding the withdrawal of the 

 ice sheet. 



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