I thought that looked like (central) Texas stuff!
I don't advise picking up artifacts "from eroded lakeshores", though. Most major Texas lakes were built (and are owned) by the Corps of Engineers. That means they are Federal land -- and removal of artifacts therefrom is prohibited by Federal law. I know for a fact that the Corps had been arresting (and fining/incarcerating -- and confiscating the boats and vehicles of) folks they catch "artifact hunting" on Texas lakeshores.
I would pretty much guess its those who are digging that they are really after.
Such as the men in the boat that were using their motor to dredge..lol
Otherwise I wouldnt worry too much about it if you are "beachcombing."
PS: Those are North Central Texas, within a 150 mile radius of DFW.
Have you been able to knapp any alibates?
That stuff is beautiful.
Sometimes you can get rough on ebay, nothing good out there right now though.