22077 - Great Collection of 3 OPHIURA SP Brittlestar Upper Ordovician Ktaoua Fm Onchopristis teeth collections which can collapse easily when

which can collapse easily when even slight pressures are applied

Rooted incisor specimen

United States ( Illinois

Although it has commonly been assumed that concretions grew incrementally from the inside outwards

It has a large

22077 - Great Collection of 3 OPHIURA SP Brittlestar Upper Ordovician Ktaoua Fm Onchopristis teeth collections which can collapse easily whenBeautiful collection of 3 specimens of Ophiura. This type of brittlestar is quite representative of the Ordovician of the South of Morocco. Its orange colors come from the limonite (iron oxide) that is the product of the oxidation of the original pyrite that mineralized these fossils.