A star among ammonites
The name of this kind of ammonite is Asteroceras, meaning ‘star-horn’. This superb example came from the Woodstone nodules near Charmouth. The shell has, in many places, stayed attached and actually shows what the creature would have looked like when alive; it is decorated with ribs, grooves and growth lines.
Look closely at the inner whorls where the shell has broken away (the darker area), and you can see the suture lines. They formed where the chamber walls met the inside of the shell. In contrast, the largest, outer whorl has no suture lines because this is the long body chamber in which the soft parts of the animal were housed.
Find out more about ammonites on the molluscs pages.