This has been identified as a sash buckle.

Front of sash buckle. Rear of sash buckle.

This relic was found in the front yard of my uncles civil war era house. Within 10 feet of this, bullets, buttons and other miscellaneous civil war relics were also recovered. It is listed on the Northern Virginia Relic Hunters forum, but so far it is not identified. It is made of brass, some gilt remaining, 2 3/8" in length and 1 1/2" at the widest point. It looks like a strap or belt went under the bar and the tab at the top was inserted in a hole...making it adjustable. I first thought it was an epaulet, but now I think it may be some type of saddle adornment.