Jackson, Ian. Northumberland Rocks — 50 extraordinary rocky places that tell the story of the Northumberland landscape. Newcastle upon Tyne : Northern Heritage, 2021. The richly illustrated and accessible book series of Northumberland, Cumbria and Durham Rocks are available to purchase from Northern Heritage.
4 Green Carts Quarry
Theme: Ancient rivers, seas and life
Location
The quarry is in the southern part of Wark Forest
Description
Green Carts is an old limestone quarry in a clearing in the middle of a sitka spruce forest. Lying on the floor of the quarry are thousands of fossils of large sea shells, a brachiopod called Gigantoproductus; they reach 15 cm across! Also there are fossils of corals and other sea creatures, all weathering out of limestone rock in the middle of Wark forest.
These rocks are about 335 million years old. The rock is called the Fourlaws Limestone and it’s from the Carboniferous period. Brachiopods have been around more for than 550 million years and there are a few species still living today. Our fossil brachiopods lived attached to a rocky sea bed.
Limestones like this are made of calcium carbonate from the shells and skeletons of billions of sea creatures, including brachiopods, together with carbonate mud. The environment at the time was a warm shallow sub-tropical sea.
The floor of the quarry has a carpet of glaucous sedge and mouse ear hawkweed with fairy flax and bird’s foot trefoil. There are lots of tiny spruce seedlings as well. In late summer see if you can find the spikes of autumn gentian in the southeast corner of the quarry. Roe deer are common and you will hear great tits and coal tits. If you are very, very lucky you may see a goshawk.