The limestones contain Globigerina and other Foraminifera, the siliceous beds are made of Radiolaria, sponge spicules and diatoms, while the red clay closely resembles the red clay of the deepest parts of the oceans.
There is also amongst the Palaeozoic group an interesting series of red slates containing Radiolaria.
Radiolaria are found in cherts in the Culm of Devonshire and Cornwall, in Russia, Germany and elsewhere.