Friday, 17 August 2018

Flora and Fauna of the Cumberland Coalfield.

While looking for fossils in the Coal Measures in a nearby ghyll, Tom found a fossil fish scale. Fish scales aren't common in the sequence and are hard to find due their small size. The scale belongs to Rhizodopsis, a Rhizodont fish, which was a large, freshwater fish that lived in the Carboniferous (and Devonian) periods in the coal swamps that formed the Cumberland Coalfield, part of the Pennine Coal Measures.
These fish were lobe-finned fishes that are most closely related to modern day Lungfish and Coelacanths. They preyed on lungfish, other fishes and tetrapods in swamps, where many plant and animal species also lived.

Rhizodopsis scale. Left: Low Loughing Beck specimen, Right: Comparative diagram for identification.
Rhizodopsis was not the only animal species to inhabit the coal swamps. Carbonicola and other freshwater mussels burrowed into the sediment and siphoned their food from the murky waters.

Left: Rhizodopsis scale, Right: Freshwater mussel species.
Surrounding the streams and pools numerous plant species inhabited the land. Their leaves and stems fell into the sediment and were preserved, and now a large array of fossil plants can be found.
The fossil flora assemblage includes:

  • Sphenopteris diliatata
  • Alethopteris decurrens
  • Neuropteris gigantea
  • Sphenophyllum cuneifolium
  • Lepidodendron lycopodiodes 
  • Calamites suckowi

Lepidodendron lycopodiodes- a scale tree (also known as a giant club moss) (top and bottom right)
Alethopteris decurrens- a seed fern (bottom right and middle right)
Neuropteris gigantea - another seed fern (middle left)

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