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.

WISCONSIN GEOL. AND NAT. HIST SURVEY. BULLETIN NO. V., PL. I.

General map showing the location of the chief points mentioned in this report. The location of the area shown in Plate [XXXVII], centering about Baraboo, is indicated.
[See larger image]

WISCONSIN GEOL. AND NAT. HIST. SURVEY. BULLETIN NO. V., PL. II.