On the Silurian System of the Lake Superior Region. 187 
In the present state of the northern peninsula, being almost an 
unbroken wilderness, and the elevation of the country occupie 
y the Silurian series but a few hundred feet above the lake, 
with no abrupt curves in the strata, by which they are brought 
to the surface, it is impossible to determine anything more than 
and it was only with the hope of acquiring more detailed infor- 
mation, that we desired more time and better opportunities of in- 
vestigation. ; 
Leaving the Escanaba, and following along the coast of the 
bay in a southeasterly direction, we soon find the limestones, Just 
described, coming out to the surface at the lake-level and scarcely 
tising above it, the character of the beds being the same as those 
seen within a mile of the mouth of the river. 
At the mouth of Ford river, the country is low and there are 
no rocks visible. The banks consist of alluvial, or drift materi- 
als, for four miles, when there occurs a long rapid over the thin- 
bedded limestone, the same in character as that at the upper mill- 
dam on the Escanaba. Proceeding towards Cedar river, we 
passed several reefs of rock and observed large slabs of limestone 
in the shallow water, which appeared identical with those at the 
mouth of the Escanaba, and lower than the thin-bedded portion — 
of the Trenton group. Upon Cedar river, there are no rocks vis- 
ible for two miles after leaving its mouth; but here, at the end 
of a mill-dam, the arenaceous and shaly bands, which occur at 
the Lower fails of the Escanaba and opposite “ Wood’s Camp,” 
oidal joints being the most numerous. 
‘rom the mouth of Cedar river to the mouth of the Menomo- 
hee, the more thickly-bedded portions of the T'renton, with lay- 
ers of Birds-eye, occur along the margin of the bay. Although 
hearly in situ, the beds have been raised and broken by the wa- 
ter, and, in some places, piled up in walls, or barriers, which have 
@ Very artificial appearance. 
_ At the lower dam, on the Menomonee, a little above the water, 
limestone is observed, in places, on the right bank, its surface be- 
Ing ground down, and grooved with drift-scratches. Its charac- 
ler is very similar to that of the Birds-eye, aud the only fossils 
0 
: Menomonee. The fossils collected were two species of Mur- 
“sonia, Pleurotomaria lenticularis, aud several Brachiopoda. _ 
