Here's a cool 1/4 plate tintype of 2 soldiers standing in front of a building with a brick pile also behind them. Back in the left side of the image there is an individual sitting that also appears to be in uniform. There is also an individual on the right side back. Both can be seen a bit better with a jewelers loop.
These soldiers are wearing 4 button sack coats. I took a photo of the image outside of its case, glass, and mat to help shows it better.