THE 



JOURNAL OF GEOLOGY 



APRIL-MAY, igo4 



ICE-RETREAT IN GLACIAL LAKE NEPONSET AND IN 

 SOUTHEASTERN MASSACHUSETTS. 



INTRODUCTION. 



Lake Neponset is the name applied to the body of water which, 

 during the final retreat of the Wisconsin ice-sheet, occupied the upper 

 portions of the valley of the present Neponset River a few miles 

 south of Boston. The existence of this lake was first pointed out 

 by Professor W. O. Crosby, who regarded it as one of a series of 

 more or less open lakes, the waters of which had gathered between 

 the general ice-margin and the higher lands bordering the north- 

 ward-sloping valleys in the region to the southwest, south and south- 

 east of Boston during the period of retreat. The more important 

 of the water bodies beginning at the west are designated by Pro- 

 fessor Crosby as Lakes Sudbury, Charles, Neponset, and Bouve. 

 The deposits and history of Lake Bouve have been discussed in 

 detail by Dr. A. W. Grabau, while the Sudbury, Charles, and 

 Neponset lakes have been defined and discussed in a more general 

 way by Professor Crosby and Mr. F. G. Clapp. 



In the writings of Crosby, Grabau, and Clapp,' the view, though 

 not definitely stated, seems to have been tacitly accepted that, although 

 there were doubtless many minor irregularities of the ice-front, the 

 margin as a whole preserved a rather definite and regular terminal 



^ For Mr. Clapp's present views see paper on " Relations of Gravel Deposits 

 in the Northern Part of Glacial Lake Charles, Massachusetts," pp. 198-215 of the 

 present number of the Journal of Geology. 

 Vol. XII, No. 3 181 



