Asterotheca
A saw cut reveals a fragmental breccia with numerous white feldspathic clasts and fine-grained lithic fragments
CaCO3 (the other forms being the minerals calcite and vaterite)
Septarian concretions or septarian nodules
Awesome specimen prepared as free standing
30858 - Nicely Preserved 1.45 Inch Harpes perradiatus Lower Devonian Trilobite Crustaceans AsterothecaHarpes perradiatus, Richter and Richter 1943 Harpes Harpetidae PaleoDB taxon number: 313570 Alternative combination: Helioharpes perradiatus Belongs to Harpes according to M. C. Ebach and K. J. McNamara 2002 Sister taxa: Harpes acuminatus, Harpes dvorcensis, Harpes escoti, Harpes fornicatus, Harpes forojuliensis, Harpes gracilis, Harpes koeneni, Harpes latilimbatus, Harpes macrocephallus, Harpes macrocephalus, Harpes neogracilis, Harpes nymageenensis,