Looks (based on catch quota info online) like they were bay quahaugs. Do you remember how deep the water was where you found them? I'm remembering now I couldn't see the bottom at all in Narragansett Bay, and I was wearing an ill-fitting borrowed pair of sneakers, so we were finding them by feel.

They were on the beach with the tide out. No way we could’ve dug for them underwater as the water would’ve filled the holes in before we got down deep enough. I recall the water was fairly shallow for a bit out but COLD!