Craig,
Thanks.
That list was for some of the damascus barrels that people were asking about at the time. It can be expanded to include;
rounded crown over a D, Delcour-DuPont, Belgium,
pointed crown over a D, Deidere, France,
Whitworth, England
Krupp, Germany
The SB&Co marking can be debated. They established a company here in Syracuse, NY. This allowed them to avoid the tariff situation. Some have suggested other companies for the marking.
The "elongated square" or rhombus, which I am beginning to suspect is an importer's or exporter's mark, as it shows up in too many places. That is to say, it shows up on barrels that also have maker's marks which can readily be identified.
Eventually it all bleeds over to the same sources as Ithaca barrels, once they took over the company.
Pete