The coordinates for this geocache place you on the pavement, near the entrance to Green Park station (on the park side of the street). You don't need to enter the station to answer, so you can do it at any time.
We're here to look at the limestone that's been used to decorate the walls and the top of the stairs. There's lots to be seen.
1) Pick a slab and describe one of the fossils you can see - describe the shape and size
2) Can you identify the fossil - use the pictures and descriptions below to help you?
3) Was this limestone created in an acidic environment or not? Give a reason for your answer.
4) Take a photo of yourself at GZ , or an identifying item, in front of one of the station signs or something interesting being careful not to reveal any of the answers to the questions.
Please submit your answers via message though the Geocaching website or by sending me an email - there is no need to wait for a response before logging your find.
Formation of fossils in limestone
Fossils in limestone are formed when dead plants or animals get buried by mud or sediment, usually at the bottom of shallow seas or lakes. Over time, more layers build up on top, and the pressure turns the sediment into limestone rock. The hard parts of the dead creature, like bones, shells, or teeth, slowly get replaced by minerals, turning them into stone.
Some animals make better fossils than others because they have hard parts that can last a long time. For example, shells, bones, and teeth are more likely to survive and become fossils than soft parts like skin or organs. Soft-bodied animals often decay quickly before they can be buried and preserved.
Limestone is a good rock for fossils because it forms in calm, underwater places where dead creatures can settle gently and be covered without being destroyed. These conditions help protect the remains and allow fossilization to happen. That's why many sea creatures, like corals and shellfish, are often found as fossils in limestone.
Sometimes, instead of finding a fossil, there are just holes or empty spaces in the rock shaped like the animal. This happens when the hard parts of the animal, like shells or bones, dissolve before they can turn into stone. This can happen if the water around them is slightly acidic, which slowly wears away the hard material. The shape gets left behind in the rock, like a mold. Later, minerals might fill the hole and make a cast, or it might stay empty. These impressions still help scientists learn about the creature that was once there.
Some different types of fossils you can see in limestone
Ammonite
Ammonites were marine creatures with spiral shells that lived in oceans, swimming in open waters and using gas-filled chambers for buoyancy.
Gastropod
Gastropods are mollusks that lived in marine environments, using their coiled shells for protection as they crawled along the ocean floor or attached to rocks.
Belemnite
Belemnite fossils are the remains of extinct marine creatures that lived in oceans during the Jurassic and Cretaceous periods. They were squid-like animals that swam in open waters, using their bullet-shaped internal shells for balance and buoyancy.
Brachipod
A brachiopod fossil is a marine organism's shell, typically symmetrical and resembling a clam.
Mollusc
A mollusc fossil in limestone shows the hard shell of the animal preserved in the rock.