Photo 1: Flat-tip Piddocks exposed from holes drilled into soft shale.
Flat-tip Piddock: Penitella penita
The common piddock is Nature's drill bit. This amazing shell looks like two halves of completely different species grafted onto each other. The rounded end is in fact the drill. It bores its way into soft rock by rotating this end. Here is another picture with the siphon extended.
