182 R. D. SALISBURY — EXTRA-MORAINIC DRIFT. 



new, but were long since recognized by President Chamberlin and have 

 been made use of by him and his assistants in field determinations. 



Correlation of Deposits. — Apart from the inherent interest winch attaches 

 to the determination of the existence of a first glacial drift south of the 

 moraine in New Jersey and Pennsylvania, this determination is likely to 

 prove helpful in another direction. 



The extra-morainic glacial drift in northern New Jersey and Pennsyl- 

 vania affords a definite starting point for determining the relation of the 

 glacial formations of the north to the coastal plain formations of the 

 eastern and southeastern United States. It may not he out of place to 

 add that the conclusion has already been tentatively reached that the 

 " yellow gravel " formation of Dr. Cook is older than the extra-morainic 

 drift. If this tentative conclusion shall prove to be correct, and if the 

 drift he first glacial, then the " yellow gravel " must he preglacial, and 

 therefore pre-Pleistocene. 



