Roberta,
 
A couple years ago we discovered a series of mounds which we believed
to be charcoal kilns in eastern Virginia. I found historic
descriptions of such features which matched fairly closely, but our
features had a few distinct differences. As I continued to do
research I discovered that what we had found were not charcoal kilns,
but tar kilns. I also found a great 18th-c ref which described tar
kilns as being built in the same basic manner as charcoal kilns.
Essentially, charcoal kilns of the colonial period may have come in
different forms, but the ones I encountered in the literature were
mounds varying from 20-40 feet in diameter, with a hollow crater in
the center. Essentially the wood to be baked was piled up and sod or
dirt was mounded all up and over it, with a flue hole left at the top
and a feeder or breather hole left near the base or sides. The
resulting feature should look something like a small earthen volcano
with a rich deposit of charcoal in the central crater.
 
One of the first tip-offs I had that our features were TAR kilns came
from the fact that they were located in a stand of pitch pines along
the margins of a swamp--very typical. Obviously, charcoal kilns would
be found in a hardwood forest. The other cluew is that the tar kilns
have channels or drains in them, leading downhill from the bottom of
the central basin, for draining off the extracted tar. At the ends of
these drainage channels--which appeared to have been
wood-lined--there were small circular cisterns for inserting a tub or
barrel to catch the tar.
 
Hope this helps.
 
Dan Mouer
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