Just acquired a nice original 1861 Tower that bears the makers name G. Marbury and an inspection mark of a Crown
over the letters S,H and what appears to be O, arranged in a triangular pattern.

Schuyler, Hartley & Graham, Federal supplier and predecessor to Remington,used a similar mark as described above substituting the "O" for a "G".

Sinclair, Hamilton and Co, Confederate supplier, used the initials S,H and C but I am unsure as to whether the Crown was incorporated above the initials. Does anyone have a detailed description of Sinclairs inspection marks?