1 06 ICE RECESSION IN NEW ENGLAND 



Only a few of the more distinct lines of recession among those 

 described in southern New England are shown. The "New- 

 ington moraine" of Katz and Keith is shown only in Maine be- 

 cause that part of it which lies in New Hampshire and Massa- 

 chusetts seems to the compiler to consist of a series of local 

 recessional wash plains and morainal embankments whose ice 

 contacts lie in parallel lines which trend perpendicular to the 

 striae. (The local moraines shown on PI. VI in New Hampshire 

 in the same axis are not a part of the "Newington moraine".) 

 The lines of moraine in western New York are mapped in some- 

 what contradictory fashion by different investigators, making 

 it difficult to select material consistently; but in the main these 

 follow the courses determined by Leverett and Taylor. 



Isobases 



These are drawn only for southeastern New Hampshire and 

 the adjacent part of Massachusetts, and are based upon detailed 

 observations and measurements by the compiler. Tarr's 50-foot 

 beaches on Cape Ann are taken as the marine limit at that point. 

 The absence of confirmatory evidence from the Salem-Boston 

 district is puzzling; and the correct course of the isobases in 

 Massachusetts is not known. Studies of the deformed water 

 planes in the Merrimac, Connecticut, and Contoocook Valleys 

 are in progress, but do not yet justify extension of the isobases 

 farther inland than here shown. The probability that the 

 "marine limits" at different localities are not even approxi- 

 mately contemporaneous makes a fuller construction of isobases 

 unwise. 



Positions of receding ice edge 



These lines, plotted by Dr. Antevs after data collected by 

 him at the localities shown, give, so far as the facts warrant, the 

 distances uncovered by the receding ice edge each century in the 

 valleys where observations are numerous. Three positions only 

 are plotted in the Hudson Valley, to show how the recession 



