Psiloceras planorbis (Sowerby 1816)
Rectangular piece of grey shale. On upper surface are 2 microconch flattened iridescent Ammonites. Oldest Ammonite in the UK.
Jurassic, basal Jurassic, Lower Hettangian, Planorbis Zone, Aldergrove beds.
Doniford bay, Watchet, Somerset.
Specimen : 5.5 x 4 x 1.2 cm.
