I found this fossil on Walton-on-the-Naze several years ago. It is heavy, weighing 158 g, and had a dark rust brown colouring which has worn off through drying and is revealing dark grey colour beneath. I think it looks like a toe bone. There is some very light flaking in a small patch on the end.

It is 7 cm x 4.5 cm at its widest points and 2.5 cm across the narrowest point.