This limestone is from the Dinantian epoch of the Lower Carboniferous. It was laid down approximately 350 million years ago in semi tropical seas. It is made up from the calcium rich shells, bones & skeletons of the fauna that was prevalent at that time. Some of their remains can be seen as well preserved fossils. Crinoid fossils are usually fragmented as they were quite delicate in life & tended to be broken up by currents after death. The Derbyshire limestone is very pure, about 98% soluble in rainwater (over time) leaving only residual clay. It is extracted for aggregate, building stone, the manufacture of cement, paper & calcium carbide. This example was quarried in the White Peak of Derbyshire. Specimens are supplied in labelled card trays.