Eastern Oyster

Habitat:

On tidal zone rocks at local beach/park. Native to eastern North and South America. In brackish and salty waters from 8–35 feet deep. In some warmer areas, they are able to live in the intertidal zone.

Notes:

I don't know specifically what this bed of bivalves is. I am assuming a species of mussel or oysters??? very "thin" for the mussel I'm familiar with and too dark and not rough enough for oysters??? Thank you. UPDATE: If ID is incorrect, please let me know. After some research and looking around the web, I believe these are Oysters.