Wisconsin tribune. (Mineral Point, Wis.) 1847-1854, 1847-12-10
VOLUME l.

L
river, displaying, in various localities, in
dications of considerable lead Iodes.
On the eastern side of the Mississippi
river primitive rocks are met with in
places from forty to sixty miles from the
river. These granite formations are i'm
portant for architectural purposes, as they
afford great variety Of the most durable,
as well as ornamental, building stones,
which, at no very distant period, will be
valuable as articles of commerce, as the
great Valley of the Mississippi, to the
south. is formed Of secondary rocks, which
are far inferior for the permanent con-
struction of cdifices.
Throughout this primitive region, the
granite rocks make their appearance in
succession of rounded knobs, elevated
from ten to fifteen feet above the waters
of the surrounding country. Their gen.
eral range is south west and northeast. =
These rocks present considerable varia-
ton in character and composition. Some
times they are hornblendic, approaching
to perfect syenite at other times, field
spartic. Some portions are massively
s;ratifed, the masses being nearly vertic-
al. On the western limits of these prim-
tive rocks, there are several large de.
posites of iron ore. The trap ranges. with
the exception of those crossing the st.
Croix river, are found on the water
courses which empty into Lake Superior,
and is the rock in which Lake Superior
copper is found, and no doubt valuable
mines Of this mineral will be, hereafter,
discovered IN these ranges, equal to any
heretofore found farther east Oh Lake Su-
perior, as they constitute Il portion Of the
same ranges. In the vicinity of these trap
ranges, the land is tllable, the soil good,
and generally covered with rich growth
of sugar maple.
At the Falls of St. Croix, fifty to sixty
miles from the Mississippi, there is a
grand outburst of green stone, epidote and
porphyritic trap, forming a series ofdykes
10 feet and more in elevation, above the
streams, and traversed by veins of native
copper, carbonate, and probably grey sui
phuret.
At the Falls Of ST. Croix, Immediately
in juxtapostion with the trap, In some
places entangled in the disrupted portions
of these rocks, are beds highly charged
with linguias and orbiculars, some, if not
all of them, probably, of undescribed spe-
cies These beds differ In Theological
character, from anything observed else
where, in the protozoic strata of the west,
and perhaps in any portion of the United
States. These angular and orbcular beds,
though often crowded with remains OF
these genera of molusca, are found to be
subordinate to quartzose sandstone, also
containing lingulas and orbiculars, prob.
ably of the same species as In equivalent
beds of Potsdam sandstone of New York
making them of groat geological interest
as they are undoubtedly the lowest fossil.
as rich IN remains of these forms of mo
lusca as any of the most fossliierous bed,
of the Ohio valley. Some distance above
these angular and orbicular beds, but ye
considerably below the lower magnetism
lines tone of Wisconsin, we have a STRAIT;
OF the Theological character of the hydrau
geological interest, as they make us &C
8 quainted with some of the earliest form
of organic existence yet brought to ligh
T.. in this country, and furnish new ciu
4, TO the iden LITIGATION of strata. The mag
netc variations of these granite and trap
= erian ranges, is often great, at times S