This is a very interesting photograph. The 72nd Pennsylvania, was also known as Baxter's or Philadelphia Zouaves. Their 1861 uniform was a Zouave uniform of blue jacket trimmed with red, dark blue vest, blue forage cap. In 1863 they went to standard U.S. uniforms. This man appears to be wearing a gray roundabout and this is either a uniform worn before the regiment got its. Zouave uniforms or else he is wearing a militia uniform. The reenfcemant stitching on the collar helped hold up the collar. Does anyone have a better idea for the uniform he is wearing?