ON THE UPPER MISSISSIPPI. 503 
extending as far as the eye could reach, occupying a width of country from two to 
three miles in extent. 
Leaving these mounds to the left, and proceeding in a northwesterly direction, 
five miles further brought us to some picturesque exposures of Lower Sandstone and 
Magnesian Limestone, projecting in rugged escarpments from the sides and summits 
of the hills, giving to the latter a peculiar castellated appearance. Towards the 
base of the hills, beds of sandstone were frequently exhibited, in nearly horizontal 
stratification, separated from each other by intervening spaces covered with a rank 
growth of coarse grass. 
Near by, we struck the Iowa opposite a deserted Winnebago village, and found 
an old Indian trail leading up the stream. Following this between two and three 
miles, we ascended the bluffs, which were found to have an elevation of upwards of 
four hundred feet. They consist of the prevailing rocks of the country,—Lower 
Sandstone and Magnesian Limestone ; the beds of the latter formation being much 
broken, and traversed by numerous fissures. The superior strata are mixed with 
much chert, and contain numerous cavities filled with calcareous spar. 
Near this vicinity Messrs. Hatfield and Clayton found small quantities of lead 
ore, and raised about a thousand pounds. 
Resuming our route down the Mississippi, I found the bluffs at Cap 4 Lai, of 
Sandstone and Lower Magnesian Limestone, four hundred and fifty feet high; and, 
a short distance below this, on Section 4, of Fractional Township 99 north, we 
found, near the water's edge, the third Trilobite bed of F. 1, with its characteristic 
fossils. 
Escarpments of Lower Magnesian Limestone, based on sandstone, continue for 
several miles on the west side of the Mississippi, with an elevation of four hundred 
to four hundred and fifty feet. 
In the southéast corner of Fractional Section 6, of Township 97, the altitude of 
the bluff is three hundred and forty-five feet. For the first one hundred and eighty 
feet, ledges of sandstone, F. 1, are partially exposed; over this rests : 
1. Thin-bedded magnesian limestone, possessing an oolitic ER ; 15 
2. Cherty beds, with concentric markings, : : : é 
3. Oolitic magnesian limestone, ; ‘ : 2 
4, Alternations of magnesian leantooe a feat Hen : 
5. Escarpment of heavy- bedded magnesian limestone, ; : ; 144 
After passing the last exposure, the bluffs recede from the river, being separated 
from it by a nearly level bench of bottom land, half a mile wide, through Fractional 
Sections 7 and 18, Township 97, Range 2 west, and 13, 24, and 26, of Town- 
ship 97, Range 3 west. 
At the point known as Painted Rock, situated in the southeast corner of Section 
3, Township 96, Range 3 west, the bluff is three hundred and seventy feet above 
the water-level, and affords a good section of the beds of Lower Magnesian Lime- 
stone, resting on about one hundred and forty-five feet of white and yellow sand- 
stone, projecting at intervals from the slope. The oolitic beds are here one hundred 
