Asteroceras smithi Sowerby 1814 with Promicroceras planicosta Sowerby
Small piece of the famous Marston Magna 'Ammonite Marble'. One surface polished to show cross section through a Promicroceras.
Jurassic, Upper Sinemurian, Obtusum Zone,'Ammonite Marble'.
Marston Magna, Somerset.
Specimen : 4 x 3.5 cm.
