0 N T II E WISCONSIN 11 1 V E 11. 



515 



1. Slope, where rocks concealed, ...... 



2. Calcareo-siliceous sandstone, ...... 



3. Soft, coarse sandstone, containing a layer of calcareo-magnesian rock, 



4. Soft, calcareo-siliceous sandstone, ..... 



5. Calcareo-magnesian rock, with remains of Crinoidea, surmounted by ) 



6. White sandstone, with dolomitic intercalations, . . 3 



7. Sandstone, with green particles disseminated, alternating witli layers of 



5 



magncsian limestone, 

 8. Slope, unexposed, 



1'.) 



Total 



201 



Opposite Upper Saukville, the hills on the river are again of drift, composed of 

 loose sand and bonlders of trap, porphyry, qnartzite, granite, and masses of mag- 

 nesian limestone, some of which would weigh several hundred pounds. Behind 

 the drift-hills, which are upwards of one hundred feet high, rise higher hills, in 

 which the rocks are partially exposed ; and, one mile above Sauk Prairie, the Lower 

 Magnesian Limestone forms a bold and rugged escarpment at the top of the bluffs, 

 which are three hundred and sixty feet high, with drift-hills in the foreground, 

 one hundred and thirty feet high, resting against the slope of the principal range 

 of hills. Above the drift is a wall of sixteen feet of brown sandstone, with silicate 

 of iron disseminated. Another wall, of eight feet of brown and white sandstone, 

 and thin intercalations of magnesian limestone, projects fifty feet above the first. 

 Between this latter and the cliff of Lower Magnesian Limestone, some oolitic beds 

 are visible. Some of the beds of magnesian limestone at this place afford a good 

 building material. The magnesian limestone, including the oolitic beds, is seventy- 

 two feet thick. 



The soil on the drift-ranges at this place is a dark sandy loam, probably some- 

 what calcareous, supporting a growth of tall grass and oak openings. 



The drift-hills skirt the banks of the river for six miles above Saukville, and 

 have an elevation of one hundred and five feet, at a point about two miles above 

 the village, where they were measured ; and two miles higher, one hundred and 

 fourteen feet, where they are half a mile from the river, with bluffs of sandstone 

 behind them, capped with sixty feet of rugged cliffs of magnesian limestone : their 

 total height is three hundred and forty-one feet. 



On Section 11, Township 10 north, Range 7 east, of 4th Principal Meridian, the 

 bluffs are two hundred and fifty feet high. Above a slope of one hundred and sixty 

 feet, where no rocks are exposed, the formation is of sandstone, F. 1, for ninety- 

 three feet. At the base of the outcrop, the layers are white and yellow, and tole- 

 rably thick; near the top they are thin, ash-coloured, and the rock consists of coarse 

 grains loosely cemented, and crumbling rapidly by exposure to the weather. On 

 the summit are many erratic blocks of trap, granite, porphyry, and magnesian lime- 

 stone. Similar boulders are found on the tops of the drift-hills, and lining the banks 

 of the river, as far as Prairie du Sac. 



The best soil is near the base of the bluffs ; that near the river is light and 

 sandy. On Section 2, Township 10, Plymouth is situated on a terrace of drift, 

 which can be traced for two miles, succeeded by low alluvial lands. 



