T hat picture of grindstone on the lake was taken in the 60's so who knows what one would find
but i would not repeat not go out collecting with out a permit and asking a lot of local people and the law enforcement about what you intent is.
there we have that out of way.
I have seen people get permits to go for Novaculite for flint napping .
here is the fence around Dan's waterstone site .
South verging angular fold within thin-bedded middle Arkansas Novaculite.
but i think for the trouble i just buy from the man himself .
when he has stones like this and the equipment to cut and flatten .