Fig. 2
From: A report on palaeontological excavations and sampling in mudrocks: some guidelines
Exceptional preservation of fossils in mudrocks. Examples from the Middle Jurassic (Aalenian) Opalinuston Formation of northern Switzerland. a ammonite (Leioceras opalinum (Reinecke 1818)) with preserved apophyses, shell dissolved but the organic periostracum preserved; b ammonite (Leioceras opalinum (Reinecke 1818)), preservation as in a, and aptychi preserved in the body chamber; c lucinid bivalve with preserved ligament; d compressed trace fossil (Planolites isp.) preserved as thin pyritized film; e small fully articulated tanaidacean crustacean; f upper jaw of a belemnite; g articulated decapod crustacean (Mecochirus eckerti Frentzen 1937); h large arm hook (Onychites) of a belemnite; i delicate trace fossil (Spirodesmos spiralis Geinitz 1867) preserved as thin pyritized film; k as yet undescribed, fully articulated multi-armed sea star