Dodgeville chronicle. [volume] (Dodgeville, Wis.) 1862-current, 1872-01-12
MINING DEPARTMENT..


existence Of an elevation of land run
ming north FROM the lead district, and
that this elevation was line Of physic-
al disturbance along which those belts
of land in the lead districts were arran-
ged, | commenced systematic investi
CATION of the strata and country to the
north Of the last belt Of mineral land
in town six.
Two important considerations led me
to adopt this course. l. 1t is usual
for mineral districts formed like this
with east and west belts crossing Il north
and south axis, to taper cut gradually,
that is, the ranges would become small
Ter, the ore deposits scarce r, or the ore
more mixed up with other material
Having noticed incidents Of this kind
before, in we'll developed mineral dis
tricts, a,ong well defined axis and
knowing that these things are govern
ed by general laws, | looked with
great deal of confidence for a mineral
belt Of some kind, to the north of the
elevation running from Blue Mounds
to Prairie du CHEN. la the next
place, the lower magnetism limestone,
and even the potsdam sandstone is ex
posed along the line where this belt
should be found, if found at ALL But
it is no easy matter to discover and de
scribe belt Of mineral land where nc
excavations have been made. The belts
of land in the lead district were not
noticed, as belts, until the present sur
vey, and it is Il question whether they
would be noticed now. but for the mi
ming excavations made along their
course.
On the north side of this elevation
the surface is very much broken, and
decl mes rapidly towards the valley Of
the Wisconsin River. This rapid de
clivity Of the surface to the north, and
the gradual dip Of the strata to the
south; brings to the surface here the
rocks that underlie the mines of the
lead district, and lets as down, as it
we're, full four hundred feet below the
surface there, on a class of rocks form
ed long before the rocks Of the lead
district had any existence. This pla-
ces us back in the history of the past
to a period when the temperature Of
the crust of the earth and other phys
zeal conditions were very different from
what they were during the formation
of the rocks of the lead district.
We cannot have too deeply impress
ed on our minds the fact, thai, in en-
tering upon the Investigation Of these
strata, we have to investigate rocks of
more ancient date, formed in a period
vastly remote. We are no longer de-
lighted with the fossil remains with
which the lime stones Of the lead dis
trict are crowded. At this period the
waters of the primeval ocean rolled
over our continent, save here and there
a narrow strip of land on which life
had not yet begun. And even the ply
steal conditions Of the sea were such
that llfe had but just a beginning there
A lonely TFilobite might now and then
have been seen lingering near the
shore, or tiny little Linglo clinging
to the rock, but beyond this there was
no sign of life This was emphaticalIy
the age of crystalization, and mineral
formations of the highest and most
beautiful forms of matter, before organ
&c forlns appeared. But few feet be-
low US here are the Azoic rocks, with |
their lines Of fracture, referred to
week or two ago, and we do we'll to
bear this in mind during our explora-
lions here.
As We descend the northern slope of
this elevation, and commence our in
in these lower, and older
formations, we find that the character
of the rock is different, although yeryl