496 
Buell—Bowlder Trains. 
almost continuous across the Janesville-Magnolia divide. Within 
this belt is a regular succession of kame-like ridges that rise 
fpm the low basins on either side of the limestone ridge just 
mentioned and gradually thin out as they approach the crest 
of the divide. Those nearest the river, however, maintain their 
massiveness even across the highest levels and show a thick¬ 
ness in well sections of from 100 to 150 feet. 
They are all abruptly cut by the deeply eroded and gravel 
filled valley of the Rock, but remnants reappear on the ridge 
area east of the river in Winnebago and Boone counties in Illi¬ 
nois, where the isolated ridges indicated upon the map were 
located by.Mr. Leverett. 6 The .series has not been traced farther 
southward, but probably disappears beneath the massive 
moraines of later formation that lie in concentric bands around 
the head of Lake Michigan. 
THE OLD SOUTHWARD TRAIN. PLATE XV. 
Area of distribution .—This area is recognized almost entirely 
by a bowlder distribution beyond the bounds of the Kettle 
moraine. A very sparse quartzite distribution has been found 
upon the area directly south from the Mud Lake ledges and east 
of the main train as traced in the description of the trains be¬ 
longing to the Green Bay lobe. This is considered to 
belong to this earlier train mainly because its quartzites 
appear farther south along the same lines in the old drift area 
bordering the Rock river valley on the east. This eastern mar¬ 
gin includes, therefore, the few occurrences of quartzites indi¬ 
cated on the map, in the townships of Koshkonong, Lima and 
Johnstown within the Green Bay lobe, and those found in the 
old drift in La Prairie and Turtle townships in Rock county 
and in Roscoe, Harlem and Guilford townships in Winnebago 
county. 
The local quartzites just noted comprise a large bowlder 
of Lake Mills quartzite, found in the erosion valley of Turtle 
creek on section 34, La Prairie, a smaller bowlder on the crest 
• F. Leverett, Special Asst. U. S. Geol. Survey, conference and manu¬ 
script notes. 
