490 DESCRIPTION OF THE COUNTRY BORDERING 
The soil on the top is a dark vegetable mould. 
Amongst the drift we found a fie erratic specimens of fawn-coloured magnesian 
lintoatondy resembling specimens which Dr. Owen brought from Red River of the 
North, and containing the same Lower Silurian fossils, Leptena alternata, which 
characterizes particularly the shell-beds, F. 3, A 
Everywhere near the surface, and scattered on the slopes and in the beds of these 
streams, near their sources, are large erratics, even on the high prairie, and these 
seem to increase in size and number the nearer you approach the summit-levels of 
the country. 
On the St. Peter’s River, seven miles above its confluence with these streams, 
above described, sandstones of F. 1 are exposed with a thickness of fifty feet. The 
grain of the rock is rather coarser and its texture more compact than heretofore 
observed on this stream.* 
Commencing at Traverse des Sioux, and extending some ten miles up the river, 
is one of those undulating prairies which contribute so much to the beauty of this 
part of the Minnesota country. The fertility of the soil and the background of 
forest will undoubtedly make this, at no very distant day, a desirable locality for 
settlers seeking a new country. The woodland abounds in linden, white and sugar 
maple, aspen, elm, butternut, and hickory, with an undergrowth of prickly ash, 
gooseberry, and grape-vines. 
Thirty-two miles above the mouth of the Mankato, is the White Earth Bluff, 
which is about seventy feet high, and situated on the left bank. There are no 
ledges of rock to be seen at this place, but merely deposits of siliceous earthy mate- 
rial, of red colour, from the presence of oxide of iron and loose fragments of brown 
and red sandstone disseminated. 
Two miles below the mouth of the Waraju, sandstone, F. 1, is capped with twenty- 
five feet of gray concretionary limestone,+ with crystals of calcareous spar dissemi- 
nated. 
The analysis of this rock, given below, indicated a much larger per cent. of carbo- 
nate of lime than is usual in the calcareous rocks of this part of Minnesota, which 
are usually highly magnesian; this bed may, therefore be of some considerable 
economical value for obtaining good lime, by burning it. Large masses of the rock 
have fallen from above, and are easily accessible. 
Near the confluence of the Waraju, three benches or terraces of prairie-land are 
distinctly observed, as indeed at many other points on the St. Peter’s. The first, or 
recent alluvial bottoms, elevated five to ten feet above the water; the second, a 
level tract of prairie, thirty to forty feet higher, which spreads out to the width of 
* In a marsh near by, I found very large and perfect specimens of Lymnea jugularis and Planorbis 
trivolvus ; some specimens of the latter measured upwards of an inch in diameter. 
+ An analysis of the concretionary limestone yielded : 
Laamonate oflime, . : ‘ ‘ : ‘ 90- 
“< ‘magnesia, ‘ ; ‘ : : : 00-6 
Insoluble matter, é : : é 4-4 
Alumina, oxide of iron, and andi gxiieae; ‘ : ‘ 3-4 
Water, 0-6 
Loss, . 1-0 
