Pat Martin makes a good point....
 
Non-US specie is routinely found on US sites predating ca. 1820-1830 here in
the Midwest, and I assume that a similar situation would be noted almost
anywhere else.   Here in Michigan, Spanish bits, English, and French coins
have all been found on early settlment sites, presumably for use as coinage.
Other coins, such as German, have been recovered in presumed keepsake or
souvenir use.
 
In fact, it seems to me that this thread was followed on HISTARCH within the
last year or two.
 
Mark C. Branstner
Great Lakes Research Associates, Inc.