it "does have" some parallel grooving along the left end radiating away from the edge which could indicate human handiwork, but...it COULD just be a rock too. how's that for a non-committed waffle response?
Natural formation with the rock. The others are blades used for scraping and defleshing hides and also used as a knife when fastened with handle.
What's that first one made out of Capt.Ahab? Looks similar to the sandstone around here, but I know that doesn't hold an edge well....