Fossil Finder Database 2022
Tools of time This ammonite, Asteroceras obtusum, comes from the Obtusum ammonite zone within the Lower Jurassic Black Ven Marls (now known as the Charmouth Mudstone Formation). Because ammonites evolved rapidly through time, the rocks that contain a particular species must be the same age (unless the fossil has been eroded and re-deposited in a younger…
A famous fossil Known as Microdoceras birchi, this is one of the most famous ammonites along the coast. It is quite distinctive with two rows of spines on each rib.The old guide books say that it is common and plentiful but, in reality, well-preserved specimens are quite rare and nearly always very difficult to prepare or…
This block is stuffed full of belemnites. Look closely and you’ll see the radiating needles of calcite crystal that preserve the solid shell (the guard). Belemnites are probably the most common fossils found on the beaches, especially around Charmouth. When the animal was alive, the pencil or bullet-shaped shell was surrounded by a soft body,…
Fossil crow’s nest? The branching base of cycad stems are beautifully preserved in Isle of Portland rocks. Quarrymen who found them thought they were fossilised crows’ nests – you can see why. Finds were much commoner 100 years ago than today. This may well reflect the move to modern machinery – fossils are less likely…
Top tree of the Fossil Forest This is probably the most complete tree recovered from the Fossil Forest when it was quarried to reach the Portland Limestone below. The forest existed for a brief period of time before becoming drowned in a saline lagoon. Thick mats of algae grew over the floor of the forest…
Jet black This wood has been flattened and carbonised (turned into almost pure carbon). All its internal detail has been lost, leaving a black, shiny, jet-like material. Indeed, the famous Whitby Jet is fossilised wood preserved in just the same way. The difference is that the jet from the Dorset coast crumbles and breaks and…
This hard block of sandstone is packed with crinoids (Balanocrinus gracilis) and starfish (the larger being Palaeocoma milleri, and the smaller, Hemieuryale lunaris). Such blocks are very occasionally found as loose boulders on the beach, and this one probably came from the Downcliff Sands. It takes many hours of skilled preparation to clean these fossils…
Petrified wood Before this wood rotted, water containing silica replaced the wood’s fibres. The silica ‘petrified’ the wood, preserving its structure. This is the same fossil wood that is found on Portland and in the Fossil Forest near Lulworth. The Fossil Forest, and Portland Limestone, extend in a wide arc inland from Weymouth, west to…
Claw back the years Unbelievably, this lobster is over 100 million years old! Compare its segmented body and claw to a modern-day lobster, and you’ll see that there is hardly any difference at all. Undamaged specimens such as this are hard to find, and even harder to clean or prepare.