Fig. 6

Ammonites from slabs of unweathered mudrocks. Compare this splendid preservation with that of Fig. 3. From Laqueoceras laqueous (Quenstedt 1856) in the left picture, preserved with the periostracum but with the shell dissolved, nothing would remain in a weathered surface exposure. The body chamber concretion of Leioceras opalinum (Reinecke 1818) in the right picture would survive on a weathered surface as isolated fragment