CORK ELATION 



389 



of these there are local unconformities, such as might be reproduced by 

 readvances of the ice-sheet with which the deposition was associated. 

 Throughout the whole of the series, however, there are no evidences of 

 interglacial soils or of periods of stream erosion ; and while it is certain 

 that the ice invaded the region at least twice, it is believed that the 

 advances simply mark substages of the same invasion, which is regarded 

 as Illinoian. 



CORRELATION TABLE 



Fishers island. 



Mississippi valley or Canada. 



Glacial. 



Interglacial. 



Glacial. 



Interglacial. 



Deposition of Wiscon- 

 sin drift. 





Deposition of Wis- 

 consin drift. 







Erosion. 





Peorian soils, 

 etcetera. 





Erosion. 



Deposition of lowan 

 drift. 







Erosion. 





Sangamon soils, 

 etcetera. 



Deposition of Mon- 

 tauk drift and 

 Herod gravel. 





Deposition of Illi- 

 noian drift. 







Deposition of Jacob 

 sand and Gardi- 

 ner clay. 





Yarmouth soils, 

 etcetera. 



Deposition of Jameco 

 gravel. 





Deposition of Kan- 

 san drift. 







Erosion. 





Aftonian soils, 

 etcetera. 



Deposition of Man- 

 netto gravel. 





Deposition of Al- 

 bertan drift. 





