558 
Van Else—The Dells of the Wisconsin. 
dell which has just begun to develop along a joint, and has a 
length of only 50 or 100 feet, may be cut down to the level of 
the water of the Wisconsin. Taylor’s Glen below Kilbourn and 
Artist’s Glen, Cold Water Canyon, and Witch’s Gulch above 
Kilbourn show very well the features described. 
About three miles above Kilbourn City are the so-called nar¬ 
rows of the Wisconsin. The river at its narrowest place is 42 
feet wide, whereas the average width away from the Narrows 
is 150 to 200 feet. The Narrows are due to the fact that the 
Wisconsin has here changed its course since glacial time. The 
length of the Narrows is about -J- mile. Above the Narrows the 
old course of the stream may be seen to leave its present chan¬ 
nel, and below the Narrows to again join the present course. 
While this old channel has not been followed personally, it is 
said to be about 1J miles in length. Because of the peculiar 
conditions which result in almost immediate base levelling of the 
side dells, and the rectangular system of joints, it is thought 
probable that side dells at the beginning and end of the Narrows 
began to develop; that because of the system of joints in two 
directions their heads intersected, and thus made the beginning 
of the new channel. At times of flood the Wisconsin backs water 
in some of the dells to a distance of from mile to 1 mile or 
more. Two dells on different systems of joints so far developed 
as to be base levelled back to the point of intersection, would al¬ 
low apart of the water of the Wisconsin at flood times to pass 
through the new channel, thus furnishing a course for a part 
of the water. In this shorter course the erosion would go on more 
and more rapidly, and finally the old longer course would be 
abandoned for the shorter one. Thus the Narrows, in rocks no 
harder than those confining the remainder of the course of the 
Wisconsin in the vicinity, are explained, and we have the un¬ 
usual phenomenon of strong river in a gorge abandoning its 
course to follow another gorge made by two small weak tribu¬ 
tary streams which had no advantage in slope. 
Steamboat Rock, a large island in the river above the nar¬ 
rows, is doubtless explained in a similar fashion. The main 
stream and the old course of the river is south of the rock. 
