This image is of a ammonite fossil plate. Ammonites seen in this plate are Promicrocerus planicosta (J Sowerby and Asteroceras smithi (J de Sowerby). It was found in Obtusum beds of the Lower Lias of Marston Magna near Yeovil England. This layer is rarely exposed except for in streambeds and when well shafts are dug. These ammonites existed during the Lower Jurassic Period. This stone was part of the collection of James of Charmouth, a 19th century geologist.
Specimen displayed at the Lyme Regis Museum in England as of August 2016.
Learn more at www.lymeregismuseum.co.uk