The Southwestward Boivlder Trains. 
493 
ridge of the Kettle moraine with its bordering overwash plain 
is strongly marked throughout this region and extends diagon¬ 
ally across the townships of Union in Rock county and Oregon 
in Dane. Beyond these is a moraine less strongly developed, 
which first emerges from the margin of the Kettle moraine near 
the center of Union township. This ridge is from fifty to one 
hundred feet high in the west half of Union. Crossing the high 
imestone ridges of Albany township its outer margin has a 
thickness of from twenty to forty feet on the crest of the divide 
but well sections on its inner slopes show a depth of one hundred 
feet of drift. As it crosses the marshy basins tributary to Sugar 
river, in Oregon township, it takes on kame-like features, form¬ 
ing broad, low ridges of stratified drift which bear a few kettle 
depressions and enclose several shallow lakes. 
This formation contains the peripheral distribution of the 
southwest train. Erosion sections exposing the stony drift 
usually show one or more quartzite fragments for each square 
rod of surface. Bowlders are not so common, however, as on 
the margin of the main train, though about twenty, representing 
each of the ledge groups, were noted on the roadsides and on the 
ridge crests in Albany and Oregon townships. The area of 
erosion and roadside sections examined in this belt aggregates 
about an acre of surface, and from them over 200 quartzite frag¬ 
ments were noted. Beyond this belt of stony till and gravel 
deposits the thin, much-weathered drift showed an almost com¬ 
plete absence of quartzite content, though several miles inter¬ 
vened between this margin and the border of the driftless area. 
The radial margins of this train are very ill defined, as its 
area was evidently crossed by the more southward movement of 
the Green Bay glacier. The quartzite distribution, however, 
both in the peripheral portion of the train and over the area 
adjacent to the outcrop indicate a direction about 50° west of 
south of the ledge groups. 
Correlative evidences of the accompanying drift movement .—The 
evidence of an earlier, more westerly glacial movemont across 
the Rock river valley afforded by this bowlder train is corrobo¬ 
rated by other data observed in the region. Among these are 
coincident glacial striations observed at several points. A well 
