192 The American Geologist. March, 1891 
not far west of Red lake and the Lake of the Woods, to the vi- 
cinity of Winnipeg, the Bird's Hill group of osars being perhaps 
deposited at the angle where this boundary of the ice-sheet turned 
back southwestward. In that course it seems to have reached 
across the lake area to the boulder-strewn escarpment of the Pem- 
bina mountain east of Thornhill, and beyond to have passed south 
along the west shore of lake Agassiz into North Dakota, to Pilot 
Knob in sec. 5, T. 154, R. 56, thence westward to the north side 
of Devil's lake, and thence north northwestward by the east part 
of Turtle mountain and along the moraine of the west part of the 
Tiger hills and of the Brandon and Arrow hills. 
The eleventh or Mesabi moraine, well developed in northeastern 
Minnesota, is probably represented by morainic accumulations 
north of Pokegama Falls of the Mississippi, about Bowstring lake, 
the head of the Big Fork of Rainy river, east of the Narrows be- 
tween the south and north parts of Red lake, and on the east part 
of the Tiger hills. Lake Agassiz had contemporaneously a length 
of more than 300 miles, from lake Traverse to near the south end 
or lake Winnipeg. Later moraines, formed at times of halt or 
re-advance, interrupting the recession of the ice-sheet between 
northern Minnesota and Hudson bay. have not been determined ; 
but I believe that the}* exist and await discovery when the glacial 
drift of that wooded and veiw scantily inhabited region shall be 
fully explored. 
The highest of the Herman beaches of lake Agassiz extends 
in Minnesota, as traced in that survey, to the north side of Maple 
lake, twenty miles east-southeast of Crookston, and probably it 
continues thence into the forest region on the east, where it is im- 
practicable to follow its course, to the vicinity of Red lake ; and 
on the west side of lake Agassiz it reaches through North Dakota 
and at least fourteen miles into Manitoba, terminating on the 
northern part of the Pembina escarpment somewhere between 
Thornhill and its northern end, that is, between fourteen and fort}* 
miles north of the international boundary. Before the formation 
of this beach was completed, the ice-sheet had retired from the 
lake area as far north as the beach extends. During pauses of 
this glacial recession the Dovre, Fergus Falls, Leaf Hills, and 
Itasca moraines were formed, showing a northward retreat of the 
ice-border across a distance of about 150 miles in central Minne- 
