Could you post a picture of the "ribbed" side? It might be, as John suggested, a forged leaf. On the other hand, the 1841 mountain howitzer smith's tools included a tool much like this (identical in shape, but 15 1/2 inches long) which is listed as the poker for working the fire. If there are no marks indicating yours was attached to something, I suspect a poker for a small forge is what you have. I might be interested in it if you can part with it.