580 GEOLOGY OF CENTRAL WISCONSIN. 



The main topographical features of the district the east and west ranges of the 

 Baraboo; the Wisconsin river, which traverses the area centrally from north to south, 

 making a great bow eastward to double the eastern point of the uniting quartzite 

 ranges; the remarkable course of the Fox river, which after flowing southwest directly 

 towards the Wisconsin, turns abruptly north when but one and one-half miles from it, 

 the two rivers traversing- a flat sand plain, without dividing ridge, and passing the one 

 into the St. Lawrence, the other to the Gulf of Mexico; the escarpment of the Lower 

 Magnesian limestone, which crosses Columbia county from S. W. to N. E., having its 

 face turned westward and much indented by the head waters of the streams tributary 

 to the Wisconsin; the gentle eastward slope of the country east of the escarpment, with 

 its streams flowing eastward to the Rock river; the sandy plain-like character of the 

 country west of the escarpment; the isolated erosion peaks and outliers that dot the sur- 

 face of this plain have all already been more or less briefly alluded to. 



The Lower Magnesian escarpment enters Columbia county on the southern side of 

 the town of Lodi, projecting in bold points that rise 250 to 300 feet above the valley of 

 Spring creek. Thence it trends northward through the eastern row of sections of that 

 town, with the same character, having on top the elevated prairie land of Arlington . 

 At the northeastern corner of Lodi, it turns nearly at right angles, crossing the north- 

 ern row of sections of Arlington in an eastward direction. Passing into the northwest 

 corner of Leeds it turns again northward, traversing Lowville from southeast to north- 

 west. In this town, though still well marked, the escarpment is much lessened in bold- 

 ness and height, because of the increasing eastward descent of the strata, and because 

 also it has in front a wide area occupied by the Madison and Mendota beds, beyond 

 which a second escarpment leads to the lower level occupied by the Potsdam sandstone. 

 From the northeast corner of Lowville it crosses the northwest part of Otsego, not far 

 from the village of Rio, and passing into Springvale about the middle of its south line 

 traverses that town in a northerly direction, projecting westward in long points. In 

 Springvale the Mendota and Madison escarpment is the most marked of the two, it pre- 

 senting long narrow and bold points projecting westward between the branches of Duck 

 creek, which head in the towns to the eastward. The main branch of Duck creek, in 

 the northern part of Springvale, has the widest valley, and has on each side the longest 

 of the Lower Magnesian points, that on the north side extending all the way to the west 

 line of the town. On this branch of Duck Creek, also, the low ground extends far east- 

 ward into the towns of Courtland and Randolph. Across the town of Scott the escarp- 

 ment presents the same character as in Springvale, the westward projecting points re- 

 ceding eastward, however, in the north part of the town, and having between them the 

 head streams of the Fox river, instead of tributaries of the Wisconsin. The remarka- 

 ble manner in which the Lower Magnesian escarpment recedes from the Wisconsin after 

 forming for so many miles the southern boundary of the valley of that stream, and the 

 bearing of this upon the former southern discharge of the Fox river system, have been 

 previously alluded to. 



Immediately south and east from the limestone edge, the country is on a level 

 with its summit, but further south and east sinks gradually with the decline of the 

 strata in those directions. Along the western part of the soutli line of Columbia county 

 the direction of the greatest descent of the strata is nearly due south: further east and 

 north, however, it veers to the eastward, being at the middle of the east line of the 

 county about due east. Still further north, in the town of Randolph, a northern de- 

 scent begins to be distinctly perceptible. The surface slopes in general correspond 

 with these changes in direction of the slopes of the strata. The greatest elevations are 

 thus evidently reached towards the southwest, where the escarpment is highest. Thus, 

 the high prairie of Arlington and Ijeeds reaches altitudes of from 450 to 500 feet, whilst 

 tin-flier east, in Columbus and Hampden, the general elevation is 200 to 250 feet less. 



