and where would the handle go ? DOH ! looks more like a plumb bob to me ? what do you think Bob ?
yeah ok maybe one of the primitive type. now my brain is more awake it seems clearerHandle fitted over the groove.
Fold a split over it and wrap below head.
Or if you're patient ,split a live limb and leave it there.
Or split a handle and tie above ,above head.
O.P. , I'm not sure if that groove has been pecked by hand from the photo.
Sure can see why it caught your eye. From a glance it certainly looks like a crude battered axe.
yeah ok maybe one of the primitive type. now my brain is more awake it seems clearer