BORDERING ON RUSH RIVER. 529 
part, consists of thick and thin layers, with numerous spheroidal concretions em- 
bedded, and the strata are arranged in horizontal beds. In Section 30, F. 2 occurs 
in bluffs, on both sides of the river, and sometimes attains to the height of ninety 
feet. In the northeast corner of Section 31, this formation is again exposed, and is 
somewhat cherty; also in Section 32, where the magnesian limestone is elevated 
to the height of one hundred and fifteen feet above the margin of the river. 
In Township 26 north, Range 16 west, there are exposures of F. 2 in the follow- 
ing sections, viz.: in Section 5, high cliffs appear near the southeast corner. In Sec- 
tion 8, the magnesian limestone occurs on both shores of the river. Ata place called 
Balsam Bluff, in the northeast corner of this section, the strata form bold and over- 
hanging cliffs, and rise to the height of two hundred feet above the margin of the 
stream. The base consists of thirty-five feet of alternations of sandstone and mag- 
nesian limestone, surmounted by thick beds of magnesian limestone, which is 
somewhat cherty towards the summit of the cliff, and is traversed by thin, vertical 
fissures, devoid of calcareous spar. Half a mile below Balsam Bluff, in the same 
section, these strata were found to attain nearly the same thickness. In Section 
9, on the east side of the river, and near the line which separates it from Section 16, 
there is a precipitous exposure of F. 2, consisting of alternations of sandstone and 
magnesian limestone at the base, with thicker beds of the latter towards the 
summit. In Section 16, these strata form bold escarpments at a number of points 
on either side of the river, and in the southern portion are underlaid by 3B 1, 
occurring in thick-bedded layers. On the east side of Section 17, near a small 
stream flowing from the southwest, are perpendicular cliffs, eighty feet in height, 
of which there is at the base thirty-five feet of alternations of sandstone and mag- 
nesian limestone. Near the mouth of Cane Creek, in Section 21, the upper mem- 
bers of F. 1 are exhibited in perpendicular cliffs, surmounted by the lower beds of 
F. 2, the latter forming the greater part of the exposure. In Section 22, a bluff, 
two hundred feet in height, was observed, composed, at the base, of F. 1, in thick- 
bedded layers, thirty-three feet through, capped with F.2. In Sections 15 and 16, 
magnesian limestone is seen projecting from the hills on either side of Cane 
Creek; and in Section 11 the same rocks were again seen on both sides of the small 
creek which traverses it. In Section 27, the rocks were observed to be quite cherty 
in their lithological characters, on the shores of the small creek which runs through 
it. In Section 28, the Lower Magnesian Limestone occurs at various points, cap- 
ping the hills of Rush River; also on the north side of a large creek, flowing 
westwardly, in the southwest part of the section; at this point F.1 was seen under- 
lying F.2. In Section 33, high bluffs occur on both shores of the river. Mr. Meek 
found the rocks here to be more cherty than at any point further up the river. 
He also saw many imperfect specimens of fossils, such as characterize the cherty 
beds in the half-breed tract opposite the mouth of the Chippewa River. The rocks 
in Sections 34 and 26 present the same characters as those in the foregoing section. 
The greater portion of Township 26 north, Range 14 west, of the 4th Principal 
Meridian, is underlaid by F.1. The Lower Magnesian Limestone (F. 2) not being 
well exposed, its eastern boundary could not be defined with a great deal of accu- 
racy; and in determining its limits in this direction, as laid down on the map, Mr. 
67 
