SURFACE RELIEFS. 425 



ship 37, range 11 east, at an elevation of about 900 feet,' and trends 

 southward through ranges eleven and ten to the north line of Portage 

 county, where it veers into range nine, which it follows southward to 

 township nineteen, "Waushara county, with an elevation gradually 

 lessening from 600 to 500 feet. Thus far the watershed has been be- 

 tween the Wisconsin and the Wolf, the northern branch of the Fox. 

 Its upper end, as far south as Portage county, is on the Archaean rocks, 

 its height being augmented by drift, and its slopes in both directions 

 gradual, although the streams are constantly broken by rock rapids. 

 South of the north side of Portage county, the rock formation is the 

 sandstone. Here also the elevation is increased by drift accumula- 

 tions, which occur in a morainic condition, of great thickness, and 

 spread over a wide extent of country east and west. The slopes in 

 both directions are very gradual. South of township nineteen this 

 divide, which is now between the Wisconsin and upper Fox, veers 

 again slightly to the west, and, crossing the southern end of Adams 

 county, is cut through by the Wisconsin itself at the Dalles, in town- 

 ship fourteen, range six, having here an elevation of about 400 feet. 

 South of here there is no proper divide between the Wisconsin and 

 upper Fox, both traversing a flat country. 



The watershed between the Wisconsin and Black rivers follows 

 nearlj' the line of the Fourth Principal Meridian from township 31, 

 where it has an elevation of about 900 feet, to township 20, where the 

 elevation is about 400 feet. As far south as township 45 this ridge 

 is on Archaean rocks, much covered by drift, whilst further south the 

 drift soon runs out and the sandstone makes up the ridge. South of 

 township 20, on nearly the same line, the high ground continues, be- 

 coming the divide between the Kiekapoo, Pine and Baraboo branches 

 of the Wisconsin, and carrying limestone on the summit. 



The high limestone prairie belt, separating the systems of the Rock 

 and Wisconsin, has already been several times spoken of. Beginning 

 outside the district, it crosses Green Lake county in a S. S. W. direc- 

 tion, enters Columbia on the north line of the towns of Scott and 

 Randolph, crosses this county in a line gradually veering to the west, 

 and, entering Dane in the towns of Dane and Vienna, turns due west, 

 in which direction it continues to the Mississippi river, breaking 

 down, however, on the line of Black Earth creek in the towns of Mid- 

 dleton and Cross Plains. On the west this divide has an abrupt, ser- 

 rated face, which increases in boldness and height as followed south- 

 ward and westward, the watershed itself reaching altitudes of 400 feet 



' Hereafter aR altitades, unless otherwise stated, are referred to Lake Michigan, which 

 is taken at 578 feet above the sea. 



