The Austin weekly statesman. (Austin, Tex.) 1883-1898, 1890-01-30
TEXAS MINERALS.
SECOND ARTICLE BY e. 4. DUMBLF,
STATE GEOLOGIsT-
IRON ORES.
An Important and Interesting Document
Showing the Location Of Ores
and Their Analyses.

Texas is rich in iron ores. Not
only are there extensive beds of linn
onltes OF various degrees of purity in
the eastern portion of the State but
in the central mineral district Com
prising Burnet, Llano, Gillespie.
Mason and parts of adjacent counties)
and in Trans Pecos, Tex, hematites
and magnetic ores occur in large
bodies, and in some places of very
high degree OF purity. The import
ance OF the occurrence of these diff
ferent varieties of ore within our own
borders can hardly be estimated. In
most Of the larger iron producing dis
tricts it is unusual TO find such guam
titles of both kinds of ore, and when,
as is generally the case, a highly su
perior grade OF iron or steel can be
made by mixture of two or more
of these varieties the missing ore has
often to be brought from great dis
tances. Thus magnetic ores, similar
to those Of the central mineral district
of Texas, are mined in the Lake
Superior region, and shipped to vari
Gus interior points, and even to
Birmingham, Ala, for admixture with
the commoner ores of these localities
Our great advantage in this regard
must therefore be readily apparent.
AS stated above, the iron ores Of
East Texas are limonites-that is, a
compound of iron with oxygen, COM
bined with a certain percentage of
water, yielding, when perfectly pure,
60 per cent OF metallic iron. These
ores are of sediment ary origin, having
been deposited from solution or sus-
pension in water. They therefore U.s.
ually contain greater or less guam
tity of impurities in the shape of sand,
clay, PHOSPHORUS sulphur, ETC., and
when either OF these impurities pass a
certain limit the ore is no longer com
mercially valuable. Thus sand is
detrimental if it exceed 10 per cent,
and the PHOSPHORUS is too high for
Bessemer ores if it amounts to one
fifth of l per cent.
These East Texas ores occur in con-
nection with the strata of the tertiary
formation, partly in that division es-
pecially characterized by the Ignite
beds, and therefore called the Eo-lig-
Mite, and partly in that portion i'm
mediately everything this, and charac-
terized by its deposits of greensand
marls, and the numerous beds of fos-
sill sea shells which it contains, and
which is known as the Claiborne, from
its most typical locality. The ores vary
greatly in physical character, as
well as in quality. Some of these are
massive like ordinary sandstone or
limestone; others are Illuminated or
have stalactitic or botryoidal struc-
ture, and in some places they show a
conglomerate structure. In color
they vary from yellow, through
orange and brown to a glistening
black, and their lustre, while mostly
dull, is nevertheless in certain varie-
ties often resinous or even glossy.
AS a result of the different condi-
tions attending their deposition, the
ores of these two regions differ con-
siderably in character, although their
mode of occurrence is very similar in
both districts.
The beds are most usually found
lying horizontally on or near the tops
of the hills and have generally no
covering other than a bed of buff
sand from a few inches to twenty feet
in thickness.
In some places, however, more es-
pecially in the southern district, this
is replaced by sillicious, ferruginious
sandstone, which is seldom more than
one foot in thickness. The upper bed
of ore is, in nearly all cases, the princi-
pal one, those that unde1lie it, when
there are such, being generally thin
ner and of poorer quality.
To the fact of the greater hardness
and consequent greater resistance Of
these beds of iron ore, is largely due
the present topography Of this region.
The strata, which for the most part,
are horizontal, have been cut through
by the drainage system of draws,
creeks and rivers, leaving flat top
hills and plateaus with steep, canyon
like banks; and it is often entirely
possible to Judge from affair whether q
hill contains ore or not, from the char
acteristic shape thus impaired to it.
The ores of the area which we have
called the eo-lignitic are of stalactitic,
botryoidal, coglomerate and geode
structure, and include the socalled
kidney ores. These varyin color from
yellow to black, and the beds them
selves vary from an inch to twelve
feet in thickness.
There have been numerous an
alyses made of the ores OF this district,
and the results differ with the locality
and character of ore. AS rule the
percentages of phosphorus and
sulphur are very low, and many an
alyses show results placing them
well within the Bessemer limits.
Analysis of specimens taken by
members OF the survey to represent
typical localities, showed the ore to
contain:
Metallic iron. ...... 1907 to 51SS per cent
Phosphorus, trace. ....................0 q. II
! Sulphur .O.37to O. II
Salt 4.36 to II IS
| This in connection with tho manu-