490 
Buell—Boivlder Trains. 
hills of adjacent drift formation. Where the strike is trans¬ 
verse to this movement, as in the Mud Lake area, the whole sur¬ 
face has been reduced to a comparative level, broken only by 
the sharp irregularities left by the plucking out of the quartzite 
blocks from the fissured and tilted strata. 
The general direction of the latest ice movement over this 
area is that of the axis of the Green Bay lobe, but its extreme 
breadth and near approach to the drift margin has given con¬ 
siderable lateral divergence to the opposite sides of the train. 
The eastern ledges show striations from 6° to 10° W. of S., and 
on the western exposures the striae vary from 25° to 34° W. 
of S. These directions correspond with the axes of the drumlin 
forms in the vicinity, and also coincide with the margins of the 
bowlder trains on either side. 
The bowlder trains from the four ledge groups within the area 
are here described together as they mingle their material on 
their margins over the remote half of their territory. The 
radial margins of this broad train are sharply defined on the 
drift surface south and south-southwest from the borders of 
the ledge area. On its east margin the scattered drumlins 
in the Crawfish and Mud Lake basin show from one to one 
and a half per cent, of quartzite drift as far south as section 
4, Watertown. It is easily made out by its content of local 
crystalline rock across the intervening townships to the east 
end of Lake Koshkonong, and is indicated by less abundant 
material southward on the east shore of Lake Koshkonong, 
across Milton township in Bock county to the outer margin of 
the moraine in the northwest corner of Harmony township. 
The western margin of this train is very sharply defined with¬ 
in the proximal limits of the area. Along the west side of 
Waterloo township the crests and east slopes of the drift 
ridges are thickly strewn with quartzite blocks while the west 
slopes of the same ridges are almost free from local drift. This 
border is traced across the intervening townships of Dane 
county to the outer margin of the moraine on section 26, Union 
township, Rock county. The peripheral border of the train has 
an extent of about seventeen miles, the train thus doubling 
its breadth in its course of thirty-five miles. 
