Dodgeville chronicle. [volume] (Dodgeville, Wis.) 1862-current, 1871-10-20
MINING DEPARTMENT.

MINING DEPARTMENT.
The importance of the question pre-
sented in my last article is my excuse for
presenting new class of phenomena, or,
evidences on this question in the present
The features of an axis of elevation We
must not expect to be very distinct on the
surface. The disintegrating and abrading
agencies which through the vast cycles OF
the past have been leveling down and lev
cling up the surface of the lead district
have almost obliterated them and to find
them unlmpaired we must examine the
lower and undisturbed beds of the strata.
10 do this, let us take our stand at a
point on the Mississippi, near the point
referred to in my last, in range number
five west, and just west of Potosi. At
this point we find the blue limestone,
down even to the water level. If from
this point we follow line due east, or
parallel with the mineral belts before re-
ferrcd to, we shall find the lower beds of
the strata gradually rising as we approach
the center of the lead district. A little to
the east of Pctosi, for instance, on a
branch of the Platte river, we find the
sandstone rising from the bed of the
stream and forming ledge of rock along
its banks, bIingiug up the blue limestone
at least fifty feet above its level at our
starting point on the Mississippi. In fol-
lowing this line across the Platte, we find
~ Lo1 &c tha ekr 20 ck,l wso
ing. Not only do we find the sandstone,
but the lower magnetism limestone that
underlies it, forming lodges from fifty to
seventy five feet high, bringing up the
sandstone and blue limestone not less
than two hundred feet above its level
west on the Mississippi. Farther east on
this line the lower beds of rock are not
sufficiently explored to enable US to de-
termine just where the summit of this e
ovation is reached, or just where it com
mences to dip on the other side.
If we take our stand on the Mississippi,
little farther north, about where the
Wisconsin river enters it, and follow
along the line Of the Milwaukee & St.
Paul railroad, we shall find section
across this elevation that will bring out
to great extent its outlines.
At this point the lower magnetism lime
stone extends down to and even below the
water level, the Potsdam sand stone form
ing the bed of the river. In extending
our examinations east from this point, we
find in a very short distance the sand,
stone emerging from beneath the valleys,
and gradually rising until it reaches a
point about the fourth principal meridian.
Here we find an elevation Of the POttsdam
sandstone from 200 to $50 feet above the
valley of the Wisconsin. river, and not
much less than 300 feet above its level at
the Mississippi. After following it along
for several miles about the same level, q
very perceptble dip sets in to the east,
and it soon disappears beneath the deep
est valleys This section not only brings
out the fact that we are crossing an eieva-
ton, or a north and south antielnal axis,
but shows us just where the summit is.
Another class of phenomena, no less i'm
portant to this question, is the drift ap-
proaehes this elevation from the east and
west and is resting on lis base all along
it's course; in some instances climbing up
its TANKS. But in no instance in the lead
district, or, as far north of it as | have ex-
.ploded, have | found single particle of
drift
This fact alone, is sufficient to prove
that this little narrow strip of land, along
which the mines and mineral veins of
Southern Wisconsin are found, and that
continues to extend north beyond them,
was we'll defined elevation at the time Of
the drift formation How far this eleva.
ton will extend north, before the vast
drift deposits of that region will cover it
is question of great importance, but can
not be settled now, for want of informa
ton.
Let Us rest here for moment, and see
what these facts. when put together will
prove for Us. In the first place, we have
a narrow strip of country running north
and south, on which we find no drift !;
there are no bouldera or pebbles, or water
worn materials, such as we find on each
side Of it. This tract OF country | have
examined personally, from, the State line
south, or may say from Galena, Illinois,
on the south, to the middle of Wood
county, on the north, not much short of
two hundred miles. have also exam.
ined the region of country to the east of
this, along the line where the drift sets IN,
from Illinois on the south, to the upper
peninsula of Michigan on the north, and
find the drift uniformly all the way.
From the Geological Reports of Iowa
and Minnesota. we find that the drift on
the west of this driftless region, follows
up closely on the west side of the Missis-
sippi, leaving US a driftless region about
the width of the lead district, running
nearly north and south, rising like an is
land ont of sea OF drift. 8
In the next place, along the center of
this driftless region, we find a crest line,
from which the strata dips in opposite d.
rections, or in other words an anticlinal
axis. This | find to be true, not only in
one place. but as far as examinations have
been made all along this line.
BREAD CAST UPON THE WATBRs.-l
In 1860 the little village of Viroqua,
county. Wis, was DESTROYED by a tor