of
fine pearls were found in the southwestern corner of Wisconsin, in
Crawford, Grant, Lafayette and Green counties. Not only were they
notable for extraordinary luster, but many were of beautiful color. The
sale of some at prices which seemed fabulous to the people of that
section, when it became generally known, caused such a scramble for
them by the natives that the streams were rapidly denuded of mussels,
and that section has become of much less importance than others since
developed. Prairie du Chien is the center of the Wisconsin market, from
which point the shells are distributed to the button factories.
The
following year (1890) pearl-bearing mussels were found in several of
the central counties of Illinois—McLean, Tazewell and Woodford, in the
Mackinaw river and tributaries, but no discovery equalling that of
Wisconsin occurred until 1897 when the Arkansas beds were discovered.
A peculiarity of this district is that whereas the unio is usually most
abundant in swift clear water having a sandy or gravelly bottom, many
are found here in the mud.
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