I found this while metal detecting and I'm stumped. Almost looks like its a dental piece of some sort...like its shaped to fit the roof of someone's mouth. Being metal and sharp edged a dental piece doesn't quite seem rite.
Love it even more! I bet it is some falsies. I live out in the back woods of Indiana and I guy down the street or back in the holler has carved his own wooden ones. I bet if he was a smelter or blacksmith he would have come up with that!
I noticed this was your very first post - so, Welcome Aboard Scott! Take a look at Sub-Forums: New York for information (i.e., clubs, etc.) directly related to your state.
It looks like an upper plate for a set of dentures. I tend to think it may have had some teeth attached to the jagged lines on the lingual surface. It should be non-magnetic but it may be silver. Dentures would have required a non-rusting, non corrosive base. Can't imagine how uncomfortable those would have been.
Formerly, when surgery was not so modern, there were prothtics for people with cleft palate or other palate defects. This could be one since I see no false teeth.