I don't think it's either one (adz or plantation hoe) in my opinion.Here's a couple hoes & a adz I found don't look like it to me.But the last pic. I'll post does remind me of it a little.So I'll say some kind of eyelet off farm machinery or like wise.Around were I hunt near the water and I find them pieces like that from sailing scooners for rigging and sorts.
Take Care,
Pete
Thanks Tony in SC & Timekiller. I was looking in one of my books and I found pictures of adzes and mattocks that were excavated from American Revolution camp sights. Pic 3 looks similar to mine and it is an adze which is suppose to be more curved and sharper than a mattock. Mine has a slight curve and a tapered edge that you can tell was sharp at one time. I'm still not sure that's what it is so any feedback would be greatly appreciated.