The Geography of the Region About Devils Lake and the Dalles of the Wisconsin

Book excerpt: This report has to do with the physical geography of the area in south central Wisconsin, shown on the accompanying sketch map, Plate I. The region is of especial interest, both because of its striking scenery, and because it illustrates clearly many of the principles involved in the evolution of the geography of land surfaces. Generally speaking, the region is an undulating plain, above which rise a few notable elevations, chief among which are the Baraboo quartzite ranges, marked by diagonal lines on Plates I and II . These elevations have often been described as two ranges. The South or main range lies three miles south of Baraboo, while the North or lesser range, which is far from continuous, lies just north of the city. The main range has a general east-west trend, and rises with bold and sometimes precipitous slopes 500 to 800 feet above its surroundings. A deep gap three or four miles south of Baraboo (Plates II, V, and XXXVII) divides the main range into an eastern and a western portion, known respectively as the East and West bluffs or ranges. In the bottom of the gap lies Devil's lake (i, Plate II and Plate XXXVII), perhaps the most striking body of water of its size in the state, if not in the whole northern interior. A general notion of the topography of a small area in the immediate vicinity of the lake may be obtained from Plate XXXVII. The highest point in the range is about four miles east of the lake, and has an elevation of more than 1,600 feet above sea level, more than 1,000 feet above Lake Michigan, and about 800 feet above the Baraboo valley at its northern base. The eastward extension of the west range (Plate XXXVII) lying south of the lake, and popularly known as the Devil's nose, reaches an elevation of a little more than 1,500 feet. The lesser or North quartzite range (Plate II) rises 300 feet to 500 feet above its surroundings. It assumes considerable prominence at the Upper and Lower narrows of the Baraboo (b and c, Plate II, c, Plate XXXVII and Plate IV). The North range is not only lower than the South range, but its slopes are generally less steep, and, as Plate II shows, it is also less continuous. The lesser elevation and the gentler slopes make it far less conspicuous. About three miles southwest of Portage (Plate II) the North and South ranges join, and the elevation at the point of union is about 450 feet above the Wisconsin river a few miles to the east. The lower country above which these conspicuous ridges rise, has an average elevation of about 1,000 feet above the sea, and extends far beyond the borders of the area with which this report is concerned. The rock underlying it in the vicinity of Baraboo is chiefly sandstone, but there is much limestone farther east and south, in the area with which the Baraboo region is topographically continuous. Both the sandstone and limestone are much less resistant than the quartzite, and this difference has had much to do with the topography of the region. The distinctness of the quartzite ridges as topographic features is indicated in Plate XXXVII by the closeness of the contour lines on their slopes. The same features are shown in Figs. 1 and 2, which represent profiles along two north-south lines passing through Baraboo and Merrimac respectively.