Appendix—geological survey. 
479 
of interest. Here, in town 21, we find rising gently from beneath the sand 
and sandstone, the ancient azoic and plutonic rocks, which unquestionably 
extend back under the sandstones and limestones of the southern part of the 
state, but here, for the first time, make their appearance as the surface rock. 
They rise very gently towards the north, and seem to have an east and west 
bearing, for I find them rising simultaneously on the Black river, Yellow 
river and the Wisconsin river, in towns 21 and 22. To the west of Black 
river and to the east of the Wisconsin river, these rocks dip again beneath 
the sandstone, as though they were, like the belt I have been describing, con¬ 
forming to this north and south “ anticlinal.” 
At first I was disposed to believe that, where this class of rocks came to 
the surface would be the outcrop of the sandstone, and its farthest exten¬ 
sion north along this line; but after exploring it for eight or ten miles I 
found a general dip again to the north, and a little further on the sandstone 
resting again on the northern as well as on the southern side. I explored 
along this (north) side on the Black, Yellow and Wisconsin rivers, and found . 
this to be uniformly the case. Although in geological formations, whose or¬ 
igin and history must be dated back to a period vastly remote from those we 
have been considering, I am inclined, nevertheless, to think _that we have 
here another of those east and west belts, or what I have called (for the want 
of a better name) lines of physical disturbance. It evidently belongs to some 
of the older systems of elevation, since the sandstone is found resting hori¬ 
zontally and undisturbed on its flanks. That it stood much higher once 
than it stands now is evident from the fact, that all over the surface are scat¬ 
tered large detached pieces of rock similar to what we find in place. Some 
of these lie scattered away to the north of the elevation, and are resting on 
the horizontal layers of sandstone. These things are among the evidences 
left us of the original altitude of this belt, and of the disintegrating in - 
fluences which, through vast periods of the past, have been leveling down 
this ancient range of rocks, uniil scarcely a trace of its original contour re¬ 
mains. 
For scientific purposes, this belt of country is full of interest, but I 
shall notice only such features as are necessary to illustrate the natural pro¬ 
ducts found here, and their practical value. 
Near what we would call the center of this belt, we find arranged mostly 
the granitic rocks, with their varying proportions of mica, quartz, feldspar 
and hornblende. Their granular condition is sometimes very coarse, at 
others very fine. Sometimes they are in the form of porphyry, at others in 
the form of gneiss, but generally very feldspathic; the feldspar almost ev¬ 
erywhere showing a tendency to decompose into kaolin. Even in some of 
those larger pieces of granite, that have resisted longest those disintegrating 
influences, the feldspar has often a coating of kaolin. Unfortunately for my 
work, the face of this rock t is almost everywhere covered, except along the 
streams. In some places with a dense forest and thick underbrush, with sev¬ 
eral feet of soil and clay; in others, with extensive marshes filled with peat 
and overlaid with moss or grass, so much so that very little can be seen with- 
