Echioceras raricostatum
Echioceras raricostatum, Bayle, 1878
Black Ven Marls, Stonebarrow, Charmouth, Dorset Coast.
Family ECHIOCERATIDAE Buckman 1913
A Zone ammonite of the Upper Sinemurian substage.
Venter unicarinate, ribs fine on inner whorls, becoming strong, straight and distinct. Fading on venter of outer whorls. Although ribs fade on venter they come to meet the strong single keel at right angles. A distinctive identification feature of this ammonite. Often in pyrite from Charmouth area, this species of ammonite is particularly susceptible to pyrite disease and should be stored in very dry atmosphere or better still in a jar of glycerin. Size 4cm across.