296 The America?i Geologist. May, 1900 
up to 3 inches long. Its masses, dark bluish in their central 
part, were readily distinguished from the yellowish gray gravel 
and sand, in which the largest pebbles and cobbles, all water- 
worn, are from 6 to 12 inches in diameter. No boulders were 
seen here imbedded ; but a solitary one, about 5 feet in diam- 
eter, was observed on the opposite side of this excavation, ly- 
ing-in the gravel 10 to 15 feet below the surface. Boulders 
are absent or very rare upon or within all parts of this esker 
series. 
The till masses in the esker are about a half mile from its 
western termination against the moraine, and about one mile 
east from the section 3, on Superior avenue, figured in plate 
VII, which may be usefully compared wdth the following ex- 
planation. They seem to indicate a subglacial origin of this 
part or stratum ; but they occur where the esker is narrowest. 
Farther east, I think that its deposition took place chiefly in an 
ice-walled canon, open above to the sky. The esker river, 
formed by superglacial drainage falling into crevasses and 
moulins, probably received the till from its ice roof ; but before 
the completion of this section of the deposit, the overlying ice 
appears to have been melted through, for no till occurs here 
above the esker gravel. 
SERIES FROM LAKE AMELIA TO LAKE HARRIET. 
A less definite esker-like series of gravel and sand plateaus, 
ridges, and hills, is interruptedly traceable in the south edge 
of Minneapolis, its length being five miles or more. Its east- 
ern beginning is nearly a mile south of the city limits, at Min- 
nehaha Heights, lying east of Mother lake and about two miles 
west of Fort Snelling. Thence it is imperfectly developed 
westward, in low hills and plateaus, past lake Amelia and Pearl 
lake, but rises to form conspicuous hills close south and west 
of the Washburn Memorial Home, their tops being about 940 
feet above the sea. The series is broken at lake Harriet, but 
again is prominent, rising to nearly the same height of 940 feet, 
in the Linden hills south and west of this lake. It also appears 
to be represented, farther north, by the hills of Lakewood 
cemetery and its vicinity, and by the plateau at the middle of 
the west side of lake Calhoun, about 60 feet above the lake. 
