I found a small one similar to yours.....I'd say it is a horseshoe because of the wear at the top of the shoe....seems like they all wear out at that point.
Thank you for all the replies found a shoe buckle 2 marbles and an old (1920'S) soda bottle within a 2 ft diameter so I'm going with this story. Small child rode his pony stopped played some marbles drank a soda. After that he and ponysome how disappeared dropping found items.