Looks like a rock that someone who knew what he/she was doing whacked (multiple times) with another rock, to me...
FWIW, I've whacked my share of rocks -- and have the scars and debitage (stone chips) pile to prove it...
"Looks like a rock that someone who knew what he/she was doing whacked (multiple times) with another rock, to me..."
What you are suggesting is that it arose as the result of design. How unscientific. Surely the shape of the rock is the result of time plus chance plus a bigger rock. This is a rock that evolved into a stone ax head as the result of a multitude of small incremental changes. (/sarcasm off)