Actinostreon  marshi (J. Sowerby)

Actinostreon  marshi (J. Sowerby)
From the Jurassic ,bajocian ,inferior oolite .
Collected from Nut Hill in Gloucester,England.
Well prepared using air abrasion,this is an odd looking bivalve,sometimes called a Denture shell, from the inferior oolite .
The species used to be called lopha marshi but was recently reclassified
The entire specimen including base cut matrix measures 75mm x 66mm