Geology of the Lake Superior Land District. 31 
The bedded trap and conglomerate are admirably exhibited on 
Keweenaw Point, and in many places in the Ontonagon district ; 
but as we have minutely described the geographical distribution 
of all the trappean rocks of this era with the associated con- 
glomerate and sandstone, in a former report, a further description 
is deemed unnecessary. 
* * * * * 
[The features of this sandstone are described as presented at 
various points north of the lake, at Presqu’Isle, Carp River, Grand 
Island,—where the variety of colors the rock presents has given 
rise to the name of “ Pictured Rocks,”—on the Menomonee River, 
White Rapids, etc.] ty 
At the White Rapids, the sandstone is again exposed, pre- 
senting very nearly the same external characters, except that it is 
less discolored, and reposes on the uptilted edges of the quartz. 
It may be seen in some of the rapids below, and reappears, for 
the last time, in the river banks, forming ledges six or eight feet 
high, about three miles above the Big Bend, in township 35, 
ange 29 
“* In this vicinity, Mr. Desor discovered, in some of the loose 
masses of this rock; other fossils than the Lingule, which are so 
characteristic of this group further to the east. These fossils 
consist of the fragments of one or more species of trilobites, 
resembling Asaphus. From the characters preserved in a single 
caudal extremity, one species is identical with that which occurs 
in the same rock on the Missisippi and St. Croix rivers. 
From the Menomonee river, the Potsdam sandstone approaches 
Within fifteen or twenty miles of the shore of Green Bay, being 
distinctly exposed on all the streams flowing into it. Continuing 
in the same direction, its easterly limit passes near the Great 
Bend in the Wolf river, northwest from the outlet of Lake 
Winnebago, From thence, meandering westerly, it follows 
nearly the course of Wolf river, crossing it in the neighborhood 
of Lake Pauwaiceen, and is thence prolonged southwesterly 
towards Green and Puckaway lakes. In the neighborhood of 
Pleasant Valley, about twelve miles west of Strong’s Landing, 
©n the F'ox river, it is exposed in several low escarpmeuts, suc- 
ceeded by the calciferous sandstone, which here presents its 
usual characters, From this region, its southern limit stretches 
to the west and northwest. The country here presents a feature 
Which continues to the Mississippi river. The hills appear to be 
outliers, capped by the calciferous sandstone or succeeding lime- 
Stones, while the valleys and the lower part of the escarpments 
are composed of the Potsdam beds. 
of Mr description of the westerly prolongation of this sandstone is from the MS. 
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