THE CLAYS OF WISCONSIN.

BLACK RIVER FALLS.
Black River Falls is located in the west central part of
Jackson county on the Chicago, St. Paul, Minneapolis, and
Omaha railroad. The only brick plant in this vicinity is
situated about eight miles north of the city at a place
called Halcyon. This plant, which is known as the Hal-
cyon Pressed Brick Yard, is owned and operated by H. A.
Bright. Mr. B. A. Bright is superintendent and ra ger
and, Mr. Perry is foreman at the plant.
The brick are made from a very much decompos schist
of pre-Cambrian age which is widely distributed along the
Black river and its tributaries known as Hall and Morri-
son Creeks. In places the shale is exposed continuously
for a quarter of a mile or more along the bank adjacent to
the river. Along one of the tributaries a thickness of from
ten to twelve feet of shale above the river is exposed con-
tinuously for over half a mile. In most places the shale
is covered with soft Potsdam  sandstone, altho -h fre-
quently the sandstone is removed and the clay is either ex-
posed at the surface or covered with various depths of
sand and gravel.
In some places the shale is almost completely kaolinized
and white. In other places the composition varies and
with it the color, which is blue, green, or buff.
The accompanying map shows the location of the plant
and the distribution of the clays in the immediate vici ity.
Where the shale is mined it is comparatively soft at the
surface but the hardness increases with depth. I e clay
can be best worked after it has been weathered on 1 3 yard
through one season. Up to the present time, however, it
has been removed directly from the bank and drie  .-or a
short time under a shed, ground in a dry pan, and trans-
ferred to the press.
No attempt has been made to carefully separate the claj
which burns white or buff from that which burns red, on
account of which many of the brick have a pink color. The
brick are in reality many different shades of red and pink

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