eULLETIN OF THE GEOLOGICAL SOCIETY OF AMERiOa 

 Vol. 18, PP. 333-350 August 16, 1907 



LATEEAL EEOSION ON SOME MICHIGAN EIVERS* 



BY MARK JEFFERSON 



{Presented by title before the Society December 28, 1906) 



CONTENTS 



Page 



Introduction 333 



River Rouge 336 



Lower Rouge 337 



Middle Rouge 338 



North branch of the Rouge 340 



Rattle run 341 



Huron river 343 



Raisin river 343 



Paw Paw river 346 



Conclusions 347 



References 350 



Introduction 



The southern part of the lower peninsula of Michigan is deeply coated 

 with drift. The drift is often very homogeneous and but moderately 

 interspersed with boulders. Toward the shores of lakes Michigan and 

 Erie the drift is covered by fine lake clays, representing the floors of 

 glacial lakes Maumee, Chicago, and their contemporaries. In tlais drift 

 the rivers of the region have carved winding valleys between grassy 

 bluffs, and themselves follow courses yet more winding on the flood-plain 

 floor. Eock is rarely encountered, being buried too deeply. The border 

 of the flood-plain under the bounding bluffs is quite irregular in plan 

 when mapped, but is habitually scalloped in curves concave toward the 

 river and of radius of curvature little greater than that of the neighbor- 

 ing meanders. Occasionally such curves adjoin, separated by sharp re- 

 entrant cusps. From 5 to 10 per cent of the bluff is bare of grass or 

 trees — a steep slope of naked clay, as shown in the picture. 



* Printed with the permission of the Geological Survey of Michigan. 

 Manuscript received \>y the Secretary of the Society .Tune 3, 1907. 

 XXIX — Bull. Geol. Soc. A.m., Vot.. 18, 1906 (333) 



