The Iron Mountain, Missouri. [Volume: 8, Issue: 1, 1888, pp. 36-45]

No. 1.]

CHARCOAL IRON WORKERS.

39

the huge marginal vein forming an irregular ellipse one thousand
by five hundred feet, as well as the interlacing veins within this
ellipse, and referring to the importance of kaolinization or decomposition of the hard porphyry rocks, Mr. Potter mentions what to
us is one of the most interesting features of the Iron Mountain
deposit, and one of the best evidences of the value of thorough
scientific inquiry.
This is what is locally known as the "old surface ore," and was
described by Prof. Potter in 1884, as follows:" "Over the whole
western side of the original hill, and dipping away with increasing
thickness, may be seen a very ancient bed of surface ore, composed
of irregular and partly-rounded fragments of black, somewhat decomposed, ore. This passes beneath the overlapping sandstone
and the limestone below, forming in the lower bed of the latter a
remarkable ore conglomerate with limestone cement, * * *
it will undoubtedly be found stretching away down the ancient
hillside to where the latter runs into the bottom of the valley beneath the Silurian beds. * h * The quantity of ore stored
up in this interesting deposit must be very large indeed, judging
from the developments already made, and the great area over
which it is found outcropping well up on the sides of the hill, and
following down the slope, always with increasing thickness beneath
the covering of hardened clays and shales. * * Comparatively little clay or foreign matter, and no hard rock at all occurs
with the fragments.of rich, black ore."
LATE DISCOVERIES.
The discovery of this mantle of iron ore surrounding the deposit formerly exploited was not accidental, but was the result of
patient study of the formation and thorough search, in the light
of advanced science, for ore which ages ago had been eroded from
the main deposit. The prophecies made four years since are being
verified to-day, and the exposures and underground workings are
truly wonderful. We believe that the investigations at Iron Mountain, Missouri, may go far to explain some of the peculiarities of
other deposits of specular iron ore.
Professor Potter, who as mining engineer for the Iron Mountain Company has charge of the development of the deposit,
*Vide JOURNAL, Vol. VI, page 27.