The two contiguous coalfield areas were often referred to as the Durham and Northumberland Coalfield(s) or as the Great Northern Coalfield.[3]
Coal seams
The following coal seams are recorded from the Northumberland Coalfield. They are listed here in stratigraphic order with the youngest at the top and the oldest/deepest at the bottom.[4] Not all seams are named and not all occur at any one locality.
^The NorthumberlandCoalfield, Coalmining History Research Centre, archived from the original on 19 July 2011, retrieved 5 December 2010
^British Geological Survey 2007 Bedrock geology: UK North 1:625,000 scale geological map, BGS, Keyworth, Notts
^"The Great Northern Coalfield: Mining Collections at Beamish Museum - Northumbria University, Newcastle UK". Archived from the original on 29 February 2012. Retrieved 19 September 2010.