Hecticoceras matheyi ammonite fossil collected from the Jurassic Oxford Clays of Woodham, Buckinghamshire. Hecticoceras is an extinct genus of ammonite which can be found in Mid to Upper Jurassic sediments. They were nektonic carnivores which fell to the sea floor upon death. These examples were preserved within an oxygen starved deep marine shelf which gave rise to the Oxford Clay Formation.These particular specimens have small, smooth evolute shells which measure approximately 1.5 cm in diameter. Supplied in a small plastic bag with an information label.