Pronounced 'BEL-EM-NIGHT', the name is believed to have originally been derived from the Greek language word 'belemnon', which is today translated as meaning the name of an object that is shaped like a dart or a javelin.

The belemnites were present on the Earth for a period spanning over 140 million years. They first appeared on Earth some 208 million years ago, during the Carboniferous period. It is currently believed that they evolved from the same ancestors as the ammonites. The belemnites became extinct about the same time that the majority of the dinosaurs disappeared. This is believed to be at the end of the Cretaceous Period, some 65 million years ago, known in paleontology as the time of the K-T mass-extinction.

Belemnites were marine animals that belonged to the classification of Phylum Mollusca and to the Class Cephalopoda . Today you would find their still living relatives, the squid and cuttlefish, within the same classification. The similarities to their modern day relatives include ink sacs and the presence of ten tentacles however, the design of their tentacles also forms a difference between them; on the modern squid they have suckers in order to grab prey, whereas belemnite tentacles had hooks.

Belemnites were believed to be efficient carnivores that caught small fish and marine animals with their tentacles, and then ate them with their beak-like jaws. It is believed that belemnites were built for speed and that they probably lived in shoals. Fossil evidence has shown that they formed a major part of the diet of Ichthyosaurs .

In several of the local dialects, belemnites are known to have been called "thunderbolts", "thunder-arrows", or sometimes even "Devil's Fingers" or "St. Peter's Fingers". It was believed that during thunderstorms, the thunderbolts are hurled to the Earth along with the lightning strike. A person being struck by lightning was therefore thought to have been killed by a thunderbolt. Thunderbolts were supposed to only found in places where lightning had struck the ground. Local folklore comments that stomach-aches can be cured by scraping off and then swallowing a little of the 'thunderbolt'.

The complete belemnite 'shell' consists of three parts; the guard, the alveolus and the pro-ostracum . The fossil remains most normally found are the part of the shell that was originally located in the tail of the belemnite. This part is usually referred to as the guard (the correct name is the rostrum, the plural of which is rostra). This guard is elongated and bullet-shaped, cylindrical and either pointed or rounded at one end. It is this end that points towards the rear of the belemnite. The hollow chamber at the front of the guard is called the alveolus.

sourced from Ammonite

The 'guard' is the part of the belemnite that is normally found as a fossil. Sometimes a fossil is found with part of the phragmacone attached. Very rarely, part of the pro-ostracum is found fossilised.

Identification of belemnites is VERY difficult. With only a minimum amount of helpful features being fossilised, the shape of the belemnite guard is a useful pointer. Although I have been unable to find a suitable cross reference of shape to fossil 'name', I have been able to create some drawings that indicate the various guard shapes that may be referred to:

Photographs

A Passaloteuthis apicicurvata Belemnite collected from the cliff face between Golden Cap and Seatown.

A Passaloteuthis apicicurvata Belemnite collected from the cliff face between Golden Cap and Seatown, with a mother-of-pearl surface.

A section through a belemnite fossil inside a limestone nodule.