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. [Illustration: 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.] [Illustration: WISCONSIN GEOL. AND NAT. HIST. SURVEY. BULLETIN NO. V., PL. II. Map of Area considered in this Report.] [Illustration: Fig. 1.--Profile along a line extending due north and south from Baraboo across the north and south ranges. The dotted continuation northward, represents the extension of the profile beyond the topographic map, Plate XXXVII.] [Illustration: Fig. 2.--Profile north from Merrimac across the quartzite ranges. The dotted continuation northward represents the extension of the profile beyond the topographic map, Plate XXXVII.] I. THE PLAIN SURROUNDING THE QUARTZITE RIDGES. _Topography._--As seen from the top of the quartzite ridges, the surrounding country appears to be an extensive plain, but at closer range it is seen to have considerable relief although there are extensive areas where the surface is nearly flat.