Discoscaphites nicolleti (Morton).
Matrix free heteromorth Ammonite with original nacreous shell intact. Nice sutures. Half way around the inner whorl the shell has been depressed downwards in two places on both sides. This is the result of an attack by a predator (fish, shark or Mosasaur.) Lovely example.
Cretaceous, Maastrichtian, Fox Hills Sandstone.
Edgemont, Fall River County, South Dakota, USA.
Ammonite : 6.7 cm diam.
