INTRODUCTION 599 



ined until the summer of 1918, after the facts had been acquired in the 

 wider surrounding territory.- 



The various proofs of Post-Glacial land uplift are clear. This con- 

 clusion runs contrary to the views in much of the later literature, and 

 the writer^s sense of duty to the truth is his apology for invading this 

 well trodden ground and for venturing to disagree with many friends 

 among the later writers on the N'ew England Pleistocene. 



The recent paper (1917), by F. J. Katz and Arthur Keith, on the 

 Newington moraine in Maine, New Hampshire, and Massachusetts, con- 

 firms the fact of late submergence. They clearly state that the last 

 deposits of the region overlie or overlap the moraine, and that "the region 

 was submerged during the building of the moraine, and the ice-front was 

 in the sea'' (82, page 29). 



The lower attitude of New England was also recognized and clearly 

 stated by M. L. Fuller in 1898 (63, pages 312, 320). 



Theoretic Discussion; Criteria 

 character of deposits 



The complex of ice-laid and water-laid deposits in the terminal 

 moraines of Long Island and Massachusetts have been interpreted as the 

 record of multiple glaciation.^^ However, the evidences of and argument 

 for Post-Glacial submergence described in this paper are not dependent 

 on any theory of events during the time covered by glaciation, whether 

 one, or two, or several ice epochs. The deposits and phenomena used in 

 the present study are wholly surficial and postdate the last ice-occupation 

 of the region, and are consequently independent of any up-and-down 

 movements previous to the last ice-invasion. 



The episode in the geologic history which is here described is that of 

 the final removal of the glacier, and the problem is to determine if the 

 surficial features agree with the theoretic conditions of (1) deep water 

 facing the retiring ice-front; or (2) shallow proglacial waters; or (3) 

 subaerial land surface beyond the ice-margin. 



2 The writer makes grateful acknowledgment of financial aid from the Research Fund 

 of the American Association for the Advancement of Science. 



3 The writer is not prepared to confidently discuss the Pleistocene history as it is 

 recorded in the morainal belts, nor to controvert the published conclusions ; but study 

 of the later, or retreatal, moraines shows that much complexity of the deposits may 

 result from merely the oscillations of the margin of one ice-sheet. It is possible that 

 the glacial history of New England has been made too complex, and that future study 

 will simplify the story. It is improbable that the Pleistocene history of New England 

 is as complicated as that of the Mississippi Valley. 



XLI — Bull. Geol. Soc. Am., Vol. 30, l6l8 



