110 THE ILLINOIS GLACIAL LOBE. 



less than Two ice invasions prior to the Iowan. Reference is made to the 

 evidence found in the occurrence or distribution of bowlders of Waterloo 

 quartzite, a subject which has been investigated in considerable detail by 

 Buell and discussed in a recent paper published in the Transactions of the 

 "Wisconsin Academy of Sciences. 1 



The earliest movement affecting the ledges of Waterloo quartzite, 

 which has been recognized by Buell, is interpreted by him to have been 

 westward. This movement is indicated by the westward transportation of 

 bowlders from the quartzite ledges, and farther south by the occurrence in 

 the marginal portion of the drift of Devonian and Upper Silurian rocks, 

 which could only have been derived from the east. Following the westward 

 movement, he thinks there is evidence of a southward movement, through 

 winch quartzite bowlders were carried into northern Illinois. He considers 

 the western margin of the ice lobe which transported this material to be 

 indicated by a " belt of thickened stony till and kame-like gravel deposits, 

 the former appearing on the ridge surfaces and the latter spreading over the 

 lower level." This supposed line of marginal deposit has been traced by 

 Buell from the point where it emerges from beneath the Kettle moraine, 

 near the line of Dane and Greene countie's, Wisconsin, southward through 

 eastern Greene County, Wisconsin, into northeastern Stephenson County, 

 Illinois. Quartzite bowlders have been discovered in this belt and over the 

 countrv to the east to points slightly beyond Rock River, but none were 

 found by Buell west of this belt, Thev are readily found as far south as 

 the latitude of Freeport and Rockford, but farther south thev are very rare, 

 and apparently represented only bv small fragments. Bnell thiidcs it 

 probable that the southward movement extended but little beyond a line 

 connecting these cities, the scattering pebbles to the south being transported 

 perhaps bv water. The southward movement is thought to have been 

 followed by a southwestward one in southern Wisconsin, with perhaps 

 westward movement in southern Illinois, by which quartzite bowlders were 

 carried southwest from the ledges slightly beyond the limits of the Kettle 

 moraine. This invasion is referred to the Iowan stage of glaciation by 

 Buell, and is correlated by him with the main loess deposition. He limits 

 its western extension to the east border of the loess. 



The interpretation made by Buell would refer the earliest or westward 



Bowlder trains from the outcrop of the Waterloo quartzite area, by Ira M. Buell : Trans. Wis- 

 consin Acad. Sci., Vol. X. 1894-95, pp. 405-509. 



