Pseudo hallmarks similar to this were used frequently in New York, both in New York City and in upstate New York; you often see the left facing lion as being associated with New York makers. Although I have not seen this particular combination of marks, the use of the crown, lion and bust in some combination is not uncommonly seen.
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Have you learned any more about the marks. I am trying to track them by date. It seems Frederick was with Erastus Barton and then on his own...which would have been a time he used that mark in NYC. He then started Marquand & Brother. Some text refers to a Marquand & Barton but I haven't seen a mark for that one yet. Any further information?