A belemnite looks like a small rifle bullet or a pencil without the lead. In Polish it was once called a “thunderbolt arrow”, because people believed it was left where lightning struck. It is the fossilised part of an extinct animal and one of the easier fossils to find on a Baltic beach.
What it is
Belemnites were marine cephalopods, relatives of today's squid. They had a soft body with a hard skeleton inside. The rear part of that skeleton, made of calcite, is what survives as a fossil. Scientists call it the rostrum.
Belemnites lived in the Jurassic and the Cretaceous and died out together with the ammonites. On the beach you find them in stones and clay that the ice sheet brought from the north. Researchers even use belemnites to date the Cretaceous boulders in the cliffs of Gdańsk Pomerania.
How to recognise one
- Shape. Long, cigar-like, pointed at one end. On the beach it is usually a few to a dozen or so centimetres long.
- Colour. Brown, honey, dark grey or black. When wet it is glossy and darker.
- Blunt end. It has a conical hollow where the rest of the skeleton sat. It is not always preserved.
- Break. When a belemnite cracks you see a fibrous, radiating pattern, like a cross-section of wood.
- Weight. It is as heavy as stone. Amber is light.
What it is not
A piece of amber feels warm and light, while a belemnite is cold and heavy. An elongated pebble has no radiating structure and no sharply pointed end. A twig or fossil wood has growth rings and a splintery, fibrous break. If you are not sure, compare the stone with a photo of a belemnite, and if you are still in doubt, post a picture in a collectors' group.
Where to look
Belemnites are Cretaceous or Jurassic, so they lie where a cliff gives up stones from glacial till. The best beaches are in West Pomerania: Rewal, Trzęsacz and Niechorze. At Rewal and Śliwin the cliff also holds Cretaceous claystones. Further east, try Jastrzębia Góra and Babie Doły.
Look at the gravel bands a storm leaves high on the beach and at the debris at the foot of fresh slumps. A belemnite often sticks out of wet sand like a small peg. Go in the morning, when the sun shines from the side, because the shape then stands out from the background.
When
The best time is the first hours after the storm peak and the days of a thaw, when the cliff slumps. The details are in the guide when to look for fossils. The current state for each beach is on the fossil forecast.
What to do with your find
- Rinse it in clean water and brush it with a soft brush.
- Do not use acids. They dissolve the calcite a belemnite is made of.
- Note the place and the date. A specimen with a label is worth more than one without.
- Take only loose finds from the beach and outside protected areas.
Do not dig belemnites out of the cliff. The cliff face slumps, and in national parks and nature reserves taking fossils is banned. We explain the rules in the guide rules and cliff safety.
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