Left, the phragmacone partially encased in a nodule harder than the surounding shale, right the guard of a belemnite (the size usually found on this beach) found in the same stretch of cliff on the same day. Belemnites were squid-like creatures, and the bullet-shaped guard was an internal structure which presumably gave the creature some rigidity. The phragmacone was the buoyancy-regulating organ. It is very rare to find belemnite fossils with the parts articulated on this coast: there is one bed to the north of Runswick where there are some fossils with the guard and phragmacone still together. Picture of an articulated belemnite fossil and article about the fossilisation of soft-bodied creatures here. Small belemnite guards appear regularly here:
I could have photographed and hacked out hundreds of small 'uns, but large specimen finds are far fewer. Can the size of the living creature be inferred from any of the fossil parts? Maybe we should have a search, and if no one else has done it, Runswick Bay may have a crack.
