This was the 1860s, so either during or immediately after the Civil War. Was this Confederate gold, either taken from people or more likely banks as southern towns were captured. For example, what happened to money in Vicksburg where 29,000 Confederate soldiers surrendered to Grant? Other nearby towns fell soon after. Gold carried by boat to Ohio, then overaland to PA. Sherman took part in this battle. How much gold did he collect marching through Georgia and Atlanta? Did he get ideas at Vicksburg? How was gold moved from West to East? Where would it stop and be kept if southern owned during the war or immediately after? Wow, what a great detective story.
Whatever gold was in the CSA in 1861 was gone, mostly overseas, well before 1865.