This looks like a petroglyph of a hand to me, but there's a few things about it that confuse me a bit like how it seems to be merging into an animal looking figure with three legs? But, it's pretty cool whatever it is.
And, then over on the bottom right a bit there's a petroglyph that kind of looks like a Centaur! Lol... When I showed my dad this he said he thought the same thing.
A Centaur is like a half man half horse, but I don't think there were horses around here during that time period and I doubt that's what the petroglyph is really supposed to be, it sure does look like one though! :D