Found within a clump of Crassostrea virginica
Didn't see any mussels clustered on rocks, found this partial horse mussel shell.
This was one of the nicest examples of Half-naked pen shell that I found, nearly intact. (I'm not sure it made it home in this condition.)
This smaller species of pen shell was much less common than stiff pen shells, but we'd see a few each day. As with other pen shells, intact examples were almost non-existent.
Stiff pen shells were by far the most abundant large bivalve on the outer beaches. Thousands of them, mainly broken into pieces, were evident...even providing a minor hazard for bare feet at times. Most were seen in the higher high tide drift piles, presumably having been tossed there by the more violent storms. This example was about 10" long, most were in that size range and even a bit larger at times.