Two remarkably similar animal head figure stones with mouths agape. The Old Route 66 Zoo Site, #23JP1222. Stacy Dodd and Rod Weber finds near Joplin, Missouri.
Animal head figure stone with mouth agape
Two stones of similar material found in close proximity which look like animal heads, of similar size and left profile orientation, have open 'mouths' and which have 'eye' divots in the right positions (all together a shared motif) can inform us with confidence that Stone Age human agency with culturally-mediated artistic motivation was involved here.
These seem to be possible 'turtle head' representations to me.
Messrs. Dodd and Weber have detected hundreds of iconic stones like this at their mega portable rock art site which one would think should be of great interest to a real Archaeological Science.