It's an iron strap buckle, but dating it will be next to impossible. The first patent on this style buckle was issued in 1905 to August F. Stenzy of Baltimore.
Thank you. I was thinking it might have something to do with straps with the toothed edge. I found it in an area where I have found a lot of ww2 maneuver relics. Tried to find something to do with that but no luck so far. Thanks for the information on it. I Will look that up.