10 BULLETIN 142, U. S. DEPARTMENT OF AGRICULTURE. 



The ice sheet which occupied the basin of Lake Erie was continued 

 southward in lobes which approximately coincided with the basin 

 of the Scioto River, that of the Maumee and Miami Rivers, and 

 another which extended westward through the Maumee Basin and 

 overspread the northeastern and central part of Indiana as far as 

 Indianapolis and the drainage of the Wabash River. From the 

 deposits formed by this glacier the plains of western Ohio and east- 

 ern and central Indiana were formed, and these are extensively 

 occupied by the soils of the Miami series. 



Another large lobe of this glaciation extended southwestward 

 through the Saginaw Bay region as far south as the northern part 

 of Indiana. To the east its margin joined that of the Huron-Erie 

 lobe, and the combined deposits of the two give rise to the rolling 

 and hilly territory which extends southwestward from the " thumb " 

 of Michigan to the vicinity of Logansport, Ind. It laid down the 

 materials which constitute the ridged plains of central Michigan 

 from Saginaw to the vicinity of Jackson and Kalamazoo. It did not 

 extend entirely to the shore of Lake Michigan, but adjoined a larger 

 lobe, which occupied the basin of Lake Michigan. Along the junc- 

 tion of these two lobes were formed deep and extensive deposits of 

 ice-borne material along the eastern border of the lake from the 

 vicinity of Newaygo to the Indiana State line. 



The Lake Michigan lobe was almost coextensive with the present 

 area of that lake, but extended slightly beyond its present bound- 

 aries, and laid down deposits which circle the lower extremity of 

 the lake, giving rise to soils of the Miami series in northern Indiana 

 and northeastern Illinois. 



Another lobe of the Wisconsin glaciation extended to the south- 

 west through the basin now occupied by Green Bay and Winnebago 

 Lake. The front of this lobe and of the smaller Delavan lobe ex- 

 tended from the vicinity of Beloit, Wis., beyond Madison and 

 Portage, and thence northward into central Wisconsin. Along the 

 line of its juncture with the Lake Michigan lobe extensive and deep 

 glacial deposits were formed which accentuate the area of highland 

 separating the Green Bay basin from that of Lake Michigan. 



When the ice sheet of the Wisconsin glaciation advanced to its 

 extreme limit it extended over a region which had previously been 

 glaciated one or more times. It filled the existing valleys and deeply 

 covered the interstream ridges and hills. Its base rested upon the 

 unconsolidated deposits of the previous invasions and upon exposed 

 ledges of consolidated rock of various character and hardness. The 

 ice scoured and eroded these surfaces, picked up masses of rock, 

 gravel, sand, and clay, and after thoroughly mixing them trans- 

 ported the material a varying distance along its path. It is prob- 

 able that a large part of this reworking and transportation was 



