130 GEOLOGY OF EASTERN WISCONSIN. 



is only when they debouch into the lowlands of the Fox river that 

 they turn southward. 



The contour of the adjacent country forbids the supposition that 

 these valleys were excavated by simple drainage erosion. Their di- 

 rection corresponds to that of the drift movement to which they are 

 undoubtedly due. They bear the distinctive marks of troughs, up 

 which the ice mass moved from the northeast, as will be explained 

 subsequently. On either hand there are vast accumulations of drift, 

 heaped up in the form of an irregular moraine, or of rounded hills and 

 parallel ridges. "When the streams reach the lower land, they follow 

 southward along the foot of the drift hills, in what was formerly, to 

 some extent at least, the bed of an elongated lake. 



It is noticeable, also, that the numerous beautiful lakes of this re- 

 gion fall into line along these glacial valleys, and owe their existence 

 to the same general cause. 



The Pike river in Keaosha county is but an insignificant stream, 

 but its course is very instructive. In the upper portion it flows in a 

 meandering manner toward the lake in the direction of the general 

 slope of the surface. But when within about one mile of the lake 

 shore, it turns abruptly southward and runs parallel to it for about 

 four miles. It formerly extended farther, but the encroachment of 

 Lake Michigan cut across the narrow tongue of clay that separated 

 the river from it at one of the bends just above Kenosha, and allowed 

 the stream to discharge at that point. But the old gorge reenters the 

 shore bluff farther down and again joins the lake at Kenosha harbor. 

 Drs. Lapham and Hoy have both previously called attention to this 

 interesting instance of lake encroachment. 



At the point where the stream now discharges, a sand bar is formed 

 which turns it southward. With a single unimportant exception, all 

 the streams, great and small, along the "Wisconsin shore of the lake, 

 so far as they have come under ray observation, are turned to the 

 southwai'd, in a similar way, by an accumulating bar at the mouth. 

 This fact has heretofore been remarked by several observers. 



It is noticed also that where piers are extended into the lake, the 

 sand rapidly accumulates on the north side, forming "made land," 

 while that which collects on the south side is inconsiderable. 



These facts show clearly that the drift along the present shore is to 

 the southward and would seem to warrant us in saying that there is a 

 southward lake current along the Wisconsin shore. This furnishes 

 the key to the explanation of the course of the Pike river. Formerlv 

 the lake stood relatively about 50 feet higher at this point than it now 

 does and extended inland beyond the position of this portion of the 



