254d. D. Dana—Drifiless Interior of North America. 
was too small for the production of a southward moving 
glacier. The southwestward direction of the scratches and of 
the bowlder-movement over the area from Wisconsin to Lake 
Winnipeg not only sustains this, but shows also that the ice 
had its greatest height over the region of greatest precipitation 
somewhere between the line from Wisconsin to Lake Winnipeg 
and beyond, and that of the Atlantic coast. More facts 
needed before the northern limit of the glacierless and driftless 
area can be laid down. 
2. Driftless area in Wisconsin. 
The charts accompanying this paper have been introduced 
here partly to exhibit the bearing of the climatal facts on the 
question as to the origin of the “driftless area” in Wisconsin, 
a description of which is given, from Professor Irving’s Report, 
winter chart (No. 1) the driftless area is almost wholly in- 
cluded within the area which has only 2 to 4 inches for the 
4area. Ag 
(No. 2), this driftless area (excepting its south end) is the driest 
found in Lucas County, Southern Iowa, 
is distant four aA S and sixty miles from Keweenaw Point, » 
its probable source. From Iowa the ice stretched eastward 
across Illinois to the Lake Michigan region. 
is southwestward prolongation of the glacier from the 
western half of Lake Superior over a region as dry as that of 
