224 Cincinnatt Society of Natural History. 
height of 300 feet. Along the Brule river, in the vicinity of the mouth 
of the Nebagamain, where the river is 300 feet above Lake Superior 
river terraces are found 30, 80, and 190 feet above the river. From 
the top of the highest terrace, or level of the surrounding country, to 
the corresponding top on the opposite side of the valley, the distance 
is about a mile. 
The lake terraces and lake deposits of sand and clay at these Asien 
in Wisconsin, show that Lake Superior has stvod at a height sufficient 
to have overflowed the highest lands in any of the States south of it. 
The driftless region in the western half of the State, is alike conclusive 
against any of the drift phenomena in the eastern part, having been 
the result of glacial action of any kind, and they both unite in testify- 
ing against a continental ice sheet, or glacial period. 
In Dakota county, Minnesota, there occurs an outlier of the St. Pe- 
ter’s sandstone, known as “Lone Rock,” owing to its standing in a 
prairie, and forming a conspicuous object for many miles in all direc- 
tions. Its summit is about one hundred feet higher than the sur- 
rounding country, and from this point a number of outliers and pin- 
nacled rocks of the same sandstone may be seen. One of these is 
called “Chimney Rock,” from its fancied resemblance to a chimney; 
and another, standing seventy feet high above the surrounding coun- 
try, is known as “ Castle Rock,” the upper twenty feet of which is now so 
slender that but few centuries will pass before it totters and falls, under 
the wearing effects of subzrial denudation. ‘These sandstone outliers 
are monuments attesting the erosion which has taken place since Silu- 
rian times, and yet, in the valleys of this county, the drift prevails and _ 
bowlders abound. In Wabasha county, we have the “'Twin Mounds,” 
and in Olmstead county, the “Sugar Loaf Mound” and the “Lone 
Mound,” and numerous isolated bluffs, attesting the erosion for the 
same period. In Fillmore county, the Trenton Group forms precipit- 
ous bluffs. It rises perpendicularly from the short talus at the base, 
which adjoins the creek, forming canons, which widen as we descend 
the streams, and which, like the monuments of other counties, attest 
the erosion through long periods of time. The weathering and erosion 
have left many scenes in the bluffs of wild and picturesque beauty, as 
at Weisbeck’s dam, in Spring valley, that, standing alone, or consid- 
ered in their relations to each other, as their bearing is found in all 
- directions of the compass, are convincing proofs of the non-existence 
of the glacial epoch. But the strongest proof, it seems, that one could 
wish against the glacial speculation, may be seen in two lonely towers, 
