Doubt the coin (cobb) came from the Ft. Capron payroll. That loss was a paymaster's chest of gold coins. When it happened in the early 1850's, U.S. was suffering from a silver shortage. Therefore, $1 gold coins were designed and minted to compensate for the shortage, to meet army payroll; and, of course, for circulation. Many people don't know the full history of where these coins were lost, at the old Indian River Inlet, although some nice history has been published in various journals and local history books.
A little over ten years earlier, young lieutenant Braxton Bragg, with company E, Third US Artillery, reoccupied Ft. Jupiter (Nov. 30, 1841). In their journey south from Ft. Marion (St. Aug.), they landed at Indian River Bar in rough surf. A boat was upset and he lost seven men to "accidental drowning." I always felt a historical marker should have been erected in that area of A1A honoring these individuals because they lost their lives while serving the U.S. army, not because of the loss of the army payroll.
Of course, in 1982, I contacted the DAR, to have them place markers on the four camps that represent the entire encompassed site of Ft. Jupiter. However, they refused because the markers would be off the beaten path of major roadways. However, a marker along A1A regarding the drownings would be seen by many.