Appendix—Geological survey. 
493 
tion of them. But if from the latter, the ore will be limited no doubt to the 
region round about the mound. 
This mound itself is a very interesting and perhaps a very important geo¬ 
logical specimen. It is composed of very hard quartzite, in places passing 
into a pure white quartz rock. It is about the size of one of those mounds 
of iron ore at Black River Falls, and occupies a very similar geological po¬ 
sition. 
Whether this bog iron ore, in its origin, is any way related to this mound 
of quartzite, is a question yet to be determined. Having made this discovey 
so late in the season, I have not attempted to develop it. I would recommend 
it, however, as one of those important places worthy of farther consideration. 
The specimens of ore in our museum of practical geology will confirm all 
that I have said in reference to its importance. 
North from the belt of country just described, my observations have been 
limited. A hasty trip to Wausau, in Marathon county, along a route confined 
mostly to the river valley, furnished the only chance for exploration. Occa¬ 
sionally, while on the way, my attention was called to objects of importance, 
such as the beautiful building stone at Stevens Point, quarried from the low¬ 
est members of the Potsdam sandstone, and the fine beds of clay for brick, a 
little to the northwest of it, on the Wisconsin Central Railroad. But I gave 
to these things only a passing notice. 
At Wausau the river crosses a well defined ledge of granite rocks, forming 
what is called the Big Bull Falls. There is nothing of especial interest along 
the river banks here, but. in following this range of rocks both to the east and 
west of the river, the evidences of its metalliferous character are met with, 
illustrated specimens of which are placed in the museum. 
It is not my intention to report on this region of country now, only to say, 
that here the granite and azoic formations are no longer confined to a narrow 
strip of country running north and south, but are spreading both to the east 
and to the west. Indeed, I think there is no doubt but that here we enter 
upon the threshold of that metalliferous belt of granitic and azoic rocks, 
which, running through Canada, enters our state through the upper peninsula 
of Michigan, and that will no doubt continue into northern Minnesota; and, 
inasmuch as this belt of rocks is known to be exceedingly rich in iron and 
copper in Michigan, close to our state line, there is good reason to suppose, 
at least, that where this belt crosses our state, will be our mineral region. 
But from this place (Wausau) to the south shore of Lake Superior, a dis¬ 
tance of over one hundred miles, there is almost an unbroken forest, unex¬ 
plored, and comparatively unknown. In entering upon the exploration of 
this region, a man can no longer hope to find a lodging place among the 
thinly-scattered inhabitants, as I have had the privilege of doing often, but he 
must take his pack on his back, and make up his mind to live in the woods, 
away from the borders, even of civilization. This, you are aware, is not the 
work of one man alone, and, before it can be accomplished, some provision 
must be made for assistance. 
Before I close this report, I will state that, as the result of my observations 
