EXPLANATION OF THE MAP ILLUSTRATING THE 



RECESSION OF THE LAST ICE SHEET 



FROM NEW ENGLAND AND 



NEW YORK 



By J. W. Goldthwait 



On this map (PL VI) have been assembled those observations 

 of glaciation and of glacial recession which, so far as known to 

 the compiler, appear trustworthy and useful as a background 

 for plotting Dr. Antevs' data. It is fully realized that no com- 

 plete and accurate map of the glaciation of this region can be 

 made without much further field work. New York State, in the 

 western Adirondacks and west and southwest of the Catskills 

 especially, awaits fuller study. Unpublished work by Woodworth 

 and by Alden in Massachusetts and by Rich in the Catskill 

 region will doubtless make some correlations much clearer and 

 more certain than those possible to show at this time. 



The chief sources of information used are as follows. The 

 titles of the publications referred to will be found, under the 

 author's name and the year, in the List of References (pp. 

 108-114). 



Direction of ice fioiv, as shown by striae and boulder dispersion 



In New Hampshire: C. H. Hitchcock (1878), J. W. Goldthwait and 

 F. H. Foster (unpublished data on boulder dispersion). 



In Vermont: C. H. Hitchcock (1861) and scattered observations in 

 more recent reports of the State Geologist by various investigators. 



In Massachusetts: E. Hitchcock (1841), B. K. Emerson (1898), and 

 drumlin axes shown on topographic quadrangles of the U. S. Geological 

 Survey. 



In Rhode Island: X. S. Shaler (1889); also drumlin axes. 



In Connecticut: W. W. Mather (1843), B. K. Emerson (1898), H. E. 

 Gregory (1906), F. Ward (1920). 



In New York: T. C. Chamberlin (1883), W. W. Mather (1843), J. F. 

 Kemp and R. Ruedemann (1910), I. H. Ogilvie (1902), H. P. Cushing 



