Hello Iain and everyone!

You are both right.

I have been working on nineteenth century potteries in Utah, USA.
From my study of the fire insurance maps (Sanborn Co.), at least two
of the Utah potteries were using some kind of open pit clay milling
apparatus.  The map displays them as a circular or square features.
They worked quite like an arrastra.  The grinding apparatus moved
through the clay, which was well mixed with water.  The ground clay
was then "slaked."  The slurry was left to settle, or in one case,
drawn off into a settling pond.  The purest clay would be skimmed from
the top of the sediment when sufficiently dry.

This dry clay was then mixed with other clays and tempers to derive a
specific clay body.  The potter selected the exact recipe depending
upon what the products would be- tableware vs. garden terra cotta.
The clays and tempers were mixed in a pug mill, of the type Iain
describes.  The bladed mixer would extrude evenly bodied raw material
for the wheel or mold.

I have not yet excavated an arrastra-styled mixing pond.  Perhaps
during October, however, so I will keep you all posted!  I suspect
that they would have been powered by horse labor, but several
potteries here had water wheels.  At least one had a series of
settling ponds intended to catch clays of various purity.  I also have
historic references to the barrel-and-blade type of pug mill, and more
significantly, there are frustrated reminiscences regarding the lack
of proper machinery due to the lack of capital and script in Utah
during the nineteenth century.

Of course, the use of the proper terms "arrastra" and "pug" may be
totally inaccurate on our part.  My maps say "clay mill."

Does that make this an academic argument?

I'm back into the field.
Cheers to all!
Tim
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Timothy Scarlett
University of Nevada, Reno
Department of Anthropology / 096
Reno, NV 89557-0096

355 West 500 North
Salt Lake City, UT 84103
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