View northwards from the future Bredon Hill area around the time of the formation of the Whitby Mudstone Formation. Area covered by sea with low lying land to the north – Dudley area of today. Water depth generally tens of metres, but varying depths over time is reflected in variations in the kind of sediments deposited, mudstone, siltstone, silty mudstone beds and rare fine-grained calcareous sandstone beds. Deeper water is associated with the settling out of the finest particles, yielding mudstones, with shallower water giving siltstones or sandstones in the shallowest – near shore or beach environment.

The marine fauna includes echinoids (sea urchins) on the sea floor, ammonites, Stenosaurus – a  fish eating reptile – appears bottom left. Bony fish, illustrated here is a shoal of Dapedium politum (around 18cm long). A Plesiosaur (3.5m long) pursues its prey belemnites – squid like creatures, where the calcareous shell of the body is frequently found as a belemnite fossil.

The Whitby Mudstone is named after its type location at Whitby on the North Yorkshire coast. Type location is where a good representative exposure of a rock formation is to be found, displaying the features that can be used as the basis for assisting identification of the type at other sites.