THE ILLINOIAN ICE INVASION 317 



The teeth of an elephant (Elephas primigenius?) were found in stratum 9 

 and may possibly be referred to the Sangamon interval. 



5. WISCONSIN 



Old forest beds are known to occur beneath the Wisconsin till in this state. 

 Alden 158 refers these to the Peorian interval, but they would seem to be equally 

 as logically referred to the Sangamon interval. The Illinoian drift sheet 

 disappears beneath the Wisconsin drift sheet south of Green Bay, and so far 

 as known there are no Iowan drift deposits in the vicinity. If the Iowan ice 

 did not reach this region, it may be that the forest of both the Sangamon and 

 Peorian intervals are represented in these ancient forest beds. Unless the ice 

 was near enough to kill the trees, there is no reason why the forests, especially 

 the coniferous species, could not have existed continuously thru both Sanga- 

 mon and Peorian time, and until they were destroyed by the Wisconsin ice 

 sheet. 



Lawson 158 records many ancient forest beds from the region of the Fox Riv- 

 er, in Calumet and Outagamie counties. These forest remains are under from 

 10 to 100 feet of red till, and are composed of moss, leaves, grasses, seeds, limbs 

 and branches of trees and saplings, many of the trees being 24 inches in diame- 

 ter. Some of the vegetation with their localities are tabulated below. The 

 names are those given by Lawson. 



Name Locality 



Pine cones and logs. Town of Harrison, Calumet County. 



Cedar, black ash, black oak, tamarack Border of Lake Little Butte des Morts. 



Linden (basswood) Forest Junction, Calumet County. 



Lawson says: "All these stumps bear evidence in their ragged heads of the 

 trees having been violently wrenched off. The most notable stump field is 

 that at Lewis Hankey's brick yard in the Town of Neenah, on the west shore of 

 Lake Little Butte des Morts. Here the removal of twelve feet of red clay in 

 brick making has uncovered several acres of stumps still standing and about 

 twelve inches high. The bed of vegetable mould and leaves is here several 

 inches thick and rests on a thin layer of blue clay. " This forest bed is more 

 probably postglacial, possibly representing the interval between a retreat and 

 advance of the Wisconsin ice (see p. 118). The forest bed encountered in deep 

 wells in various parts of the Green Bay — Lake Winnebago region is probably 

 of Sangamon age and there is every reason to believe that this deposit underlies 

 a large area of the drift. Several well sections north of Appleton afford ex- 



"• Science, N. S., XXIX, p. 557. 



151 Bull. Wis. Nat. Hist. Soc, II, p. 170, et seq. 



