please help!!! i know nothing about seashells

[paul monfils]

These appear to be Lucine Clams (family Lucinidae). I'm not certain which species. Perhaps Lucina pensylvanica. They have the right shape but look rather smooth for that species. They could be worth $.50 to $1.00 as matched pairs in prime condition. However, single unmatched valves of bivalve species generally are not of interest to collectors.