One half of bivalve shell from river Foss

One half of bivalve shell from river Foss

Observation - One half of bivalve shell from river Foss. Description: Found in a kick sample taken from the Foss. (River approx 75cm deep at this point - levels slightly elevated due to recent heavy rainfall) Apologies for the bad photos - I didn't realise they weren't very clear until I got home. Spherical object insid

Found in a kick sample taken from the Foss. (River approx 75cm deep at this point - levels slightly elevated due to recent heavy rainfall)

Apologies for the bad photos - I didn't realise they weren't very clear until I got home. Spherical object inside shell on 2 of the photos is an air bubble. In the 1st photo the shell contains sediment which I thought was remains of the bivalve but later succeeded in emptying out. I appreciate that it is difficult to identify the species from these pictures!