With apologies for not getting into this discussion sooner:

At two sites where I have worked (Faneuil Hall in Boston and the
Metropolitan Detention Center in Philadelphia) we had large collections of
both sugar cones and sugar jars. As the illustrations on the Alexandria web
site and in Diderots's Encyclopedia show, sugar cones of various sizes were
placed into jars during the sugar manufacturing and purifying process.
What we found at Faneuil Hall and at the MDC site was that the sugar cones
themselves were finely made; the difference was that at the Boston site it
looked as if there was one source for the cones and at MDC there were
several, at least some of which were European.  However, at both sites -
especially at the Philadelphia site where we had many more of the sugar
jars - the sugar jars appeared to be of local origin, based on their
similarities (paste, temper) to locally made redwares.  What we thought was
that sugar cones, since they are a specialized form, would not be made by
all potters but that the jars, which only needed to be sturdy, would be
bought from local potters by the sugar makers.  The form of the jar from
Connecticut fits with the sugar jars that we found in Philadelphia with its
ovoid body, large flat base, and heavy rim.  I agree that it was most
probably made in America and now it needs to be compared with local
redwares.  The apparent shell temper (the white spot in the photo? and the
incised line around the shoulder are interesting.

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