The geological heritage is the reason that the battle was fought at the muddy ford. The only breach in the impermeable moraine material was at Fulford where the wet land trapped between the York and Escrick moraines could drain into the river Ouse.
The moraine is the hard material created by glacial action. It is often associated with the melting of a glacier and this is known as a terminal moraine.
The map is based on BGS maps and our surface surveys.