ABSTRACTS OF PAPERS 



103 



shiftings of the ice movements were such that the outer moraine of one icelobe 

 may not be the correlative of the outer moraine of a neighboring icelobe. For 

 example, the outer moraine of the Green Bay icelobe is known to be older than 

 the outer moraine of the Des Moines icelobe. So also the Shelbyville and 

 Bloomington morainic systems of central and eastern Illinois are both older 

 than the outer moraine of the Green Bay icelobe. From this it may be seen 



r 



f drifts V 



P>-e -/("a* Saw • 



Hear San. 



Illi n o t'a y% JCbwy n . I 



TltdWiconsin 



Figure 1. — Map of the Des Moines Icelobe 



that it is unsafe to carry correlations of moraines from one icelobe to another 

 merely on the basis of numbering them first, second, third, etcetera. A con- 

 tinuous tracing of the moraines must be made. The Altamont moraine is 

 likely to be of about the same age as the Port Huron morainic system of the 

 Huron and Michigan basins and of Glacial Lake Whittlesey. 



Presented extemporaneously. 



Discussed by Morris M. Leighton, with reply, by the author. 



