Personal and Scientific News. 
129 
in and about the Boston basin are referable to a series of 
glacial lakes along the southern and western borders of the 
basin. These lakes, which existed between the receding mar¬ 
gin of the ice-sheet and the watersheds of the streams tribu¬ 
tary to Boston harbor, were subject to great variations in 
outline, area, and level. During the period of their maximum 
and most interesting development, the general trend of the 
ice margin was from east to west along the southern border 
of the basin, and thence north and northwest across the 
western end of the basin from the Blue hills to the high¬ 
lands of Weston and Waltham, 
Along the south side of the Boston basin, in Hingham, 
Weymouth, Braintree, Randolph, and Quincy, was formed 
lake Bonne (named in honor of Mr. Thomas T. Bouve, a 
former president of the Boston Society of Natural Histoiy), 
some twelve miles long. Its different levels, as determined 
by successively lower outlets, first, southward into North 
river, and later eastward into Cohasset harbor, were approxi¬ 
mately 140 feet above the sea (shown by the modified drift 
tract in Hingham called Liberty plain), 70 feet (Glad Tidings 
plain), and 50 feet (the Lower plain). [These sand and 
gravel plains, all situated in the township of Hingham, with 
the general geology of this township, including its formations 
of granite and diorite, melaphyr, conglomerate, sandstone, 
and slate, also noteworthy eskers and many large drumlins, 
are well described by Mr. Bouve in the History of Hingham, 
vol. i, 1893, pp. 1-74, with five geological maps and seven 
figures in the text.] 
Other glacial lakes were formed in the upper basins of the 
Neponset and Charles rivers. At their highest levels (240 to 
300 feet above the present sea level) these lakes were inde¬ 
pendent, and were tributary, respectively, to the Taunton and 
Blackstone rivers. But at the level of 200 feet they were 
confluent, and had a common outlet, into the valley of the 
Taunton river. Still later, an outlet was opened eastward 
along the south side of the Blue hills into lake Bouve at a 
hight of about 160 feet. The plains formed during this 
final stage of the Charles-Neponset lake extend eastward 
across Wellesley and Needham into Newton and West Rox- 
bury, and northward across the broad water-parting (now 
occupied by lake Cochituate) between the Charles and Sud¬ 
bury rivers, and thence, apparently, down the valley of the 
Sudbury and Concord rivers into Billerica. 
The western edge of the inclosing lobe of the ice-sheet 
appears to have receded eastward more rapidly than the 
southern edge receded northward, so that the ice continued 
to form a barrier across Boston harbor after it had disap¬ 
peared from all the country between the Blue hills and 
