The times., 1898-10-09
TREATISE ON CLAYS.
The State GeoIogfst of MaryIan
Prepares n Report.

The Stute Geoloefst of Maryland
Prepares Report.
| Baltimore. Oct. S-Prof William Bull
lock Clark, State geoiogist. is formulat-
! ing plans for the publication of a large
volume by the geological department. de-
voted exclusively to the clay resources of
Maryland and the commercial value of
the clays. Men have been collecting in
formation concerning the clays for sew
eraI months. and the geological part of
| the investigation is nearly completed.
To accurately fix the commercial value
of the various clays and to describe their
uses, Prof. Clark will secure the services
OF one of the few clay experts in the
country, who will arrange the data al
ready collected and put it into shape.
There are only three or four men in
the country" said Prof. Clark, .'who have
made clays the study of their lives, and
will try to have one of these men work
with US. The State is very rich in clays,
| and especially the finer quality of clay.
or kaolin, which is one of the principal
ingredients in the manufacture of fine
porcelain ware and is also used in max
ing wall paper.
The clays of Maryland suitable for
economic purposes are widely extended
occurring in a great number of different
formations. They are mostly in the east
ern and southern portions of the Stat
underlying broad areas of count y. Tg.-
portant clays also occur in the c. LraI
and western parts of Maryland. They
are suitable for the making of brick,
terra Gotta. fire brick and pottery. Those
most extensively used now are from the
Columbia and PatapSco formations, and
the center of the industry, as far as
brickmaking is concerned is in Balti-
more. The fire clays of Allegany County.
OF which there are large deposits, rank
among the very best in America, and are
a very valuable resource.
THE clays OF the Columbia formation
cover the surface of the lower level in
the region about Baltimore, and to the
country south and east they generally
consist of a yellowish or brownish clay
or loam which grades downward into
coarse sand or gravel They are highly
regarded by the clayworkers for certain
classes of products. Much of this clay
near Baltimore has been worked out, out
it is still capable of being developed in
the southern and southwestern portion of
the land about Middle Branch and other
sections of the country in adjacent coun-
ties
The cIays of the Patapsco formation
are developed along belt that extends
along the northeast to the southwest,
across the State, passing right through
Baltimore All this, and even around
Washington. the clay has been extensive
" worked, and has yielded high grade va
rieties The highly carbonaceous iron ore
claws of the Arundel formation have also
been used considerably to the south and
southwest of the city. The ciays of both
these formations have been employed for
a variety of purposes, but are capable
of being put TO much larger uses than
any TO which they have already been
put.
THE manufacture of fire brick has been
for fifty years one of the characteristic
industries of Maryland, and the bricks
made from the fire clays of Pottsvile
forma tion in Allegany County, are re-
garded as the best in the country. The
main fire clay deposit. our information
tells US. lies near the bottom of the coal
measures, and the red clay ranges from
eight TO twenty feet in thickness. 1t is
divided into two varieties, the hard and
soft clay The hard clay is of gray
color, shading almost to black. 1t is not
plastic. and disintegrates very little from
exposure to weather. The soft clay is
much lighter. is plastic. and crumbles
very readily under atmospheric infiu-
ences. The two most valuable charac-
teristics of this clay are its freedom from
potash. and the large proportion of silica
10 alumina The clay industry has
grown rapidly in Importance in recent
years. and the value Of the output in 1896
was 81. .T53 003.
Maryland is also well provided with
the finer clays, the porcelain materials
The three principal requisites to the
~ 1-.fva
quartzD feldspar and china clay or kao-
lin. The flint is widely distributed
through the rocks of the whole crystal
line portion of the Piedmont Plateau,
and is especially abundant in Cecil, Har-
ford Baltimore, Carroll and Montgomery
Counties. The best feidspar and kaoiin
produced in America are obtained with
in radius of fifteen miles from the com
mon corner of Maryland, Delaware and
Pennsylvania. 1t has been worked ex-
tensively in all three of these States and
shipped to potteries all over the country |
Kaolin is really decomposed feldspar,
and is a most valuable product. 1t occurs
in masses or pockets resulting from the |
decay of feldspathic granite. and Is Oft |
en- found mixed with impurities The |
residual kaolin is much purer although |
it, too, has TO be washed to free it from |
mica and quartz.
THE flint which is used in connection |
with the kaolin in the manufacture of !
porcelain wares. is employed largely in |
Baltimore. but has also been shipped ex-
tensively out of the State 1t has many |
uses besides that of porcelain, being used |
in the making of crockeryware wall pa |
per, sand paper, tiles, soap and paints. |
The total value of these materials pro-
duced in Maryland during 1896 was s25,-
657"