pottery is not very dense so it's among the first things to get washed away. which is great if you can follow it back to where it came from. dence items like stone get left behind it's like panning for points...ha ha
I don't know anything about beaches, i haven't left the state of ohio actually i havent left within 3 counties for over 20 years. i don't get out much.
a lot of people really don't understand how is the waterways here collect and protect things in a very low oxygen the environment. part of the reason why there's that much pottery is because that's how well preserved the site is.. bone tools are very common. unless its extraordinary I stopped keeping pottery years ago. based on markings and materials used as temper it can tell a good story though.