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The ore outcrops on Iron Range mountain occur within a compara-
tively narrow, band-like area 6 miles long and striking nearly north and
south. At every mineralized outcrop the structure seems to be nearly
vertical or to dip westward at angles of 75 degrees or higher, whereas the
general strike of the strata is east of north and the dip is to the west at
angles that decrease from an average value of 40 degrees in the north
to 5 to 10 degrees in the south. It is certain, therefore, that the ore does
not occur at a constant horizon and cannot be of sedimentary origin.

The general character and nearly vertical attitude of every mineral-
ized occurrence, their general north-south strike, their occurrence so far
as known only within a long, narrow, band-like area, and the fact that in
several instances they form nearly continuous outcrops 200 yards long,
are all features indicating that the ore outcrops belong to a system of
mineralized zones, striking north and south, inclined at very high angles
and, in a general way, vein-like in structure.

Both sedimentary and igneous rocks are involved in some of the
mineralized areas, but in other instances only sedimentary rocks are evident.
The introduction of the vein quartz and the hematite took place after
the consolidation of the igneous rocks, for they are veined, impregnated,
and partly replaced by these two minerals. All the igneous rocks certainly
do not belong to one body, although all may be essentially contemporaneous
and products of a single deep-seated source. It has been claimed by some
who have examined the deposits on Iron Range mountain that the
mineralization is due to the igneous bodies. But these bodies are not
confined to the narrow strip within which the iron ores occur and, therefore,
those observers who advocate a direct igneous origin for the ore, in searching
for some feature peculiar to the long, band-like area of mineralization,
have been led to infer that the two igneous areas outcropping respectively
on the south brow of the ridge and several miles farther north in the vicinity
of the Maple Leaf claim, belong to an extensive crosscutting body not
of the nature of a dyke or a sill. As already stated in discussing the general
geology of the locality, the present writer is of the opinion that the outcrops
at these two localities belong to two or perhaps a single sill 100 feet or
more thick. If, as is thought to be the case, the igneous rocks of the long
band of mineralization are in no way peculiar to that band, then no reason
remains for assuming that the igneous rocks directly gave rise to the
mineralization. The igneous rocks and the mineralization may be distinct
results from a common cause and the igneous bodies as structural features
may have influenced the localization of the mineralization.

The invariable presence of both vein quartz and hematite in the
mineralized zones indicates a common source for the two minerals, but
primarily the hematite does not occur as a constituent of quartz veins,
though in places sparingly present in them. The two minerals seem
to have separately formed. Possibly some of the quartz appeared first,
for instances were noted of the hematite penetrating and partly replacing
vein quartz. The zonal structure characterizing various outcrops seems
to indicate that the mineralization progressed in stages. The breecia-
like material seen in several places does not appear to be a true breccia,
for the individual fragments seem still to be in place relative to one another.
The general structure is as if narrow, north-south zones of the rock had
been greatly fractured and then invaded by solutions depositing hematite
and quartz. In numerous instances it seemed also as if the hematite