I was sure I had read about these somewhere but after many fruitless internet searches I decided to move on. The next day in the “throne room”, I was reading a back issue of my Charlton Catalogue, Canadian Coins and THERE IT WAS!!
In the catalogue they give a brief history of early Foreign Coins in Canada including France, England, Spain, Portugal, Spanish America, and the U.S.A. From the catalogue…
The most important coinages in circulation during the French regime (1600 – 1760) were a group of billon pieces collectively called sols (or sous) marques. In 1640 the French government called in all douzains and counterstamped them with a small fleur-de-lis in an oval to change their rating to 15 deniers.
Of course these 12 denier pieces, now rated at 15 deniers, were sent to the colonies (New France).

Now that I had a starting point, I used the Numista database (France / billon / 23-25 mm) to identify the undertype as
https://en.numista.com/catalogue/pieces111188.html Lucky for me it is a one year type.
And now the rabbit hole is completely open:
1. Past auctions with prices realized on the many different douzain undertypes.
2. King Charles IX became King at age 10!
3. Walter Breen suggests these were the original “Black Doggs” mentioned in the Connecticut law of 1721.
4. And on and on and on………
I know it doesn’t look like much but it did circulate twice. I’ll add this to my Canadian Colonial collection and send an addition request along to the French Colonies referee.
PS. An interesting link to the Department of Special Collections, University of Notre Dame https://coins.nd.edu/ColCoin/ColCoinContents/Contents01.html
