Hildoceras bifrons Bruguiere.
Matrix free specimen from an old collection. Two of the inner whorls have an injury of some kind disrupting the shell. Right out of the Alum Shales at the top of the cliffs at Kettleness. Zonal index fossil.
Jurassic, Upper Toarcian, Alum Shales.
Kettleness, Yorkshire.
Ammonite : 12.5 cm.
