APPENDIX-GEOLOGICAL SURVEY. 
409 
Here we have a new fact, and a very important one, namely, 
a mechanical force acting beneath the strata of the lead dis¬ 
trict, and giving character to its phenomena. This fact sheds * 
new light on onr investigations, and enables us to take higher 
and more intelligent grounds from which we can see a contin¬ 
uation of parallel elevations, such as the Baraboo Hills and 
other ridges, and foldings of the strata extending away into 
the far north. These facts indicate strongly another fact, 
namely, the presence of a north and south axis of elevation to 
which these east and west elevations and belts of mineral land 
belong as subordinate features, crossing it at right angles, lim¬ 
ited to it in its eastern and western extension. If this be a 
fact, we shall doubtless find here not only tlie physical basis 
that underlies the phenomena of the lea*d district as its cause, 
but a line of physical disturbance along which other, and per¬ 
haps more important ore districts may be found. But before 
we accept it as a fact let us submit it also to a rigid test. 
In order to put this in a tangible form so as to examine the 
facts to the best advantage, let us take the length of these belts 
as the width of the lead district, and from each end draw a 
line north. Within these lines we shall find the following 
facts, which of themselves are sufficient to prove the existence 
of the north and south axis above referred to. 
/ 
(1.) If we take a narrow strip of land near the center of 
the belt within these lines, say three ranges on the east, and 
one on the west of the fourth principal meridian, four ranges 
in all, we shall find in this little narrow strip more mines, and 
mines from which more ore has been raised than from all the 
lead districts outside of it, notwithstanding it includes in width 
fourteen or fifteen ranges or townships; I should be within the 
bounds of truth if I were to sav three times the amount. With- 
W N 
in these four ranges of townships the ore deposits are near each 
other, and often very extensive, but as we extend east or west 
from them they become few and far between, and often, though 
not always, small. In connection with this I will notice the 
fact that within this narrow strip of land all of our zinc depos¬ 
its are .found. Indeed, we may strike off the range to the 
