Breen (Encyclopedia, p. 110) says that the earliest record of their existence is by Bishop Watson in 1789, cited first by Crosby, pp. 305-06. Crosby writes that they are described in Watson's Chemical Essays (Dublin, 1791, though Breen [p. 693] says the preface is dated Feb. 9, 1786). Watson thought that these were emergency coins in base metal, like the Vienna siege pieces of 1529 (though he was mistaken in thinking that the latter were made of lead).

However, in Eric Leighton's NUmiS Worthy (Old Numismatic News) 1752-1800 (a book I learned about though The E-Sylum!), an item from the Nova-Scotia Gazette & Weekly Chronicle for Jan. 4, 1780 is quoted in part. It reads:

It is difficult to read this as anything other than a reference to pewter dollars issued by the (American) Congress no later than 1779. Andrea should track down the original issue (the whole poem is 80 lines long) to see whether any other clues are present.

Also, it is possible that researchers have been looking in the wrong year for evidence of the Continental dollars. We are so used to U.S. coins being minted in the year they are dated that we forget about things like the Pine Tree shillings, dated instead to the year of authorization. Perhaps the discussion of pewter dollars took place as late as 1778 or 1779, with the date of 1776 used in honor of the Declaration of Independence.

To read the earlier E-Sylum article, see:THE MYSTERIES OF THE CONTINENTAL DOLLARS(www.coinbooks.org/esylum_v15n41a21.html)