Here is a nice Czech Cystiod of the species Dendrocystites barrandei. The Fossil shows a good plate stucture. The Dendrocystites fossil itself mesures about 48 x 18 mm.
Location:
Chrustenice , Barrandian area, Czech Republic
Size Matrix:
about 117 x 67 mm
Age:
Middle Ordovician, Llandeilo, Letná Formation (About 464 mill. Years old)