418 GEOLOGY OF CENTRAL WISCONSIN. 



ant the Yellow and Lemonweir rivers. Yellow river heads in 

 township 25, in the adjoining corners of Wood, Jackson and Clark 

 counties, and runs a general southerly course nearly parallel to the 

 "Wisconsin for over 70 miles, the two gradually approaching one an- 

 other and joining in towship 17, range 4 east. The Yellow has its 

 Archaean and sandstone sections, the former exceedingly rocky and 

 much broken by rapids and falls, the latter comparatively sluggish 

 and without rock rapids. The upper portions of the river extend 

 into the pine regions, and much logging is done in times of high 

 water. The water powers are of great value. The Lemonweir is also 

 a large stream. Heading in a timbered region in the southeast corner 

 of Jackson county, it flows southward for some distance through 

 Monroe, and entering Juneau on the middle of its west side, crosses 

 it in a southeasterly direction, reaching the Wisconsin in section 24, 

 township 15, range 5 east, having descended in its length of some 70 

 miles about 200 feet. 



The " Dalles " of the Wisconsin, as already said, is a narrow pass- 

 age cut by the river through the high grounds which, after bounding 

 its valley on both sides for many miles, have now gradually approached 

 and joined. The total length of the gorge is about seven and one- 

 half miles. At the upper end, about two miles north of the south 

 line of Juneau county, the river narrows suddenly from a width of 

 over one- third of a mile to one of not more than 200 feet. Through- 

 out the whole length of the passage the width does not ever much 

 exceed this, whilst in one place it is only fifty feet. The water in the 

 gorge is very deep, although immediately above it there are broad 

 sand flats with scarcely enough water at low stages to float a canoe. 

 The perpendicular sandstone walls are from fifteen to eighty feet in 

 height, the country immediately on top of them being about 100 feet 

 above the river. From this level, about midway in the passage, there 

 is a rapid rise in both directions to the summit of the high country 

 on each side. In several places branch gorges deviate from the main 

 gorge, returning again to it; these are evidently old river channels 

 and are now closed by sand. The streams entering the river in this 

 portion of its course make similar cations on a smaller scale. 



At the foot of the Dalles the Wisconsin enters upon the last sec- 

 tion of its course, and also upon the most remarkable bend in its 

 whole length. From a nearly southerly course it now turns almost 

 due east, in which direction it continues with one or two subordinate 

 turns southward for about seventeen miles, through low sand banks, 

 as far as Portage. Here it bends abruptly south again, and, 

 reaching its easternmost point at the mouth of the Baraboo, soon 



