Mussel

I finished off a work application this morning and then started doing some jobs in the garden. Before it got dark I went for a walk down by the river and saw lots of empty mussel shells. I’m not sure what kind … Swan mussel perhaps … and I imagine there’s a very full otter or some other river dwellers nearby perhaps … 
I was delighted to read that there’s a Depressed River Mussel and I think it looks a bit like one but they are rather rare I gather.

Finishing off application for next bit.