Check out the bayo at this link:
http://egun.de/market/item.php?id=2850675

I have never seen anything like this before. The hilt design and what few markings there are very strongly suggest it was manufactured by Providence Tool Co. along with their contract for the Turkish M.1874 Peabody Saber bayonet, and as such, I would guess it is some kind of trials or experimental piece that was pitched to the Turks. But this is all an educated guess.

Anyone out there have any idea??

That is one strange bayonet. I looked in my reference guides and found nothing. I wonder what the scabbard looks like.

Thats a new one on me!!

It takes me long time to find this one. Here is the information:
US experimental trench (trowel) bayonet making by General Edmund Rice in the middle of 1870. Only few pieces were made.Seems like this one is extremely rare (if not a fake). I try to convert pics, because the original is in DjVu format.

Reference book in Russian language. A.N.Kulinsky "World Bayonets"