Kosmoceras Spinosum Macroconch Ammonite

This absolutely stunningly preserved ammonite is a fine example of iron pyrite preservation. 

Henrici subzone, Stewarby Memeber, late Callovian, Lamberti zone, 160 myo. Marston Mersey, Gloucestershire. 

Ammonite size 10 cm x 8 cm.