History of Texas, together with a biographical history of Milam, Williamson, Bastrop, Travis, Lee and Burleson counties : containing a concise history of the state, with portraits and biographies of prominent citizens of the above named counties, and personal histories of many of the early settlers and leading families

HISTORY VP TEXAS. 163

Cement JMaterials.-Cements are of two
kinds,-natural, or hydraulic, and artificial,
or Portland.
Natural, or hydraulic, cement is made from
certain clayey limnestones, which, when burned
and ground, have the property of setting or
becoming hard under water. Portland cements
are of similar character, but are made
by artificially mixing the limestone and clays
in the proper proportion.
Materials for both characters of cement
exist in abundance within the State. The
limestones of certain beds of the ('retaceous
are clayey enough to make cement when
properly calcined and ground, and the same
properties are claimed for some of those
found in the Tertiary, but our tests have so
far failed to bear out the claim. Some of the
limestones belonging to the Clear Fork beds
of the Permian might answer if the percentage
of magnesia was not too great.
The materials for Portland cement are,
however, more abundant, and the product of
so much better quality as to render the
natural cement a matter of comparatively
small importance. The Austin chalk is rather
widespread in its distribution and adjacent to
clays of almost any required grade.
The entire practicability of the manufacture
of Portland cement has been shown by
the two factories which have undertaken it,
one at San Antonio, the other at Austin.
The former supplied much of the cement
used in the erection of the present capitol
building, and it was of very excellent quality.
Plate' of Paris is produced from gypsum
by driving out the percentage of water
which is chemically combined with it. Its
manufacture on any desired scale is entirely
practicable in the Permian region of Texas,
where many beds of gypsum of great purity
occur.

Sand for mortar, plaster, etc., is found in
many places. The Cretaceons is perhaps the
area in which it is scarcest, and it can be
brought in from either side. The locations
will be more fully discussedd in the descriptions
of counties.
METAi.8 AND (IRES.
Iiron.-Probably the most important of
our ore deposits are those of iron, which in
various forms are found in many parts of the
State.
Beginning at the Louisiana line with a
breadth of nearly 150 miles, stretching southwest
in a-gradnally narrowing belt and probably
fading out in Caldwell county or just beyond,
there is found a series of bills of
greater or less elevation which are capped
with ferruginated material, varying from a
sandstone with a small amount of oxide of
iron in the matrix, to limonite ores of high
grade. Of this division only a few of the
counties of east Texas have been fully examined,
but enough has been done to show
the probability that the greater amount of
workable ores of this belt lie east of the 96th
meridian, although there may be localities
west of that line at which ores of value
occur. Theee ores are associated entirely
with rocks of the Tertiary and later periods.
In the Cretaceous no iron ores of any consequence
are known except in the extreme
west, where deposits of ochre seem to occur
in connection with strata belonging to the
Fredericksburg division of the Lower Cretaceous
series.
There are only a few ores of any value
found in the carboniferous area, and those of
the Permian are not of much importance.
The central mineral region, however, contains,
in connection with its deposits of older

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163

MISTORY UF TEXAS.

Lewis Publishing Company, publisher. History of Texas, together with a biographical history of Milam, Williamson, Bastrop, Travis, Lee and Burleson counties : containing a concise history of the state, with portraits and biographies of prominent citizens of the above named counties, and personal histories of many of the early settlers and leading families. Chicago. The Portal to Texas History. http://texashistory.unt.edu/ark:/67531/metapth29785/. Accessed July 31, 2015.