96 ICE RECESSION IN NEW ENGLAND 



son, N. Y., and the northern border of Massachusetts where this 

 crosses the Connecticut River agrees with the trend of Taylor's 

 recessional moraines in the Berkshire Hills and with the general 

 direction of the ice movement there. 



Their Contribution to the Problem of the Glacial 



Correlation of the Great Lakes Region 



and New England 



One of the great problems in the Quaternary geology of North 

 America is the correlation of the ice retreat in New England with 

 that of the Great Lakes region. Through the detailed studies of 

 Leverett and Taylor the conditions in the last-mentioned area 

 are well known. Morainic lines marking successive ice fronts 

 are mapped and correlated from the Dakotas eastward to 

 western New York. But the correlatives of these moraines in 

 eastern New York and New England are unknown. 



A comparison of the ice retreat in the two regions, at the first 

 glance, suggests more differences than correspondences. The 

 disagreement, however, is more ostensible than real, and may 

 essentially be due to the different topographic conditions. Most 

 conspicuous is the great abundance of stadial moraines in the 

 Great Lakes region and the practical absence of them in New 

 England. The basins now occupied by the Great Lakes brought 

 about the development of big ice lobes which easily pushed for- 

 ward and, favored by the flatness of the land, built continuous 

 though often weak moraines, while in hilly New England the ice 

 probably readvanced shorter distances and could not pile up 

 any coherent ridges. Some of the faint moraines in the lake 

 region might perhaps rather be ridges of ground moraine than 

 moraines accumulated along the ice front. Whether all the 

 differences between the two regions are due to topographic 

 conditions or not is difficult to tell. It seems possible that there 

 was disagreement also in other respects, most likely in ice supply. 

 It is practically sure, however, that the retreat in both districts 

 was determined primarily by an amelioration of climate and 

 that temperature played the chief role also for the readvances. 



