Flintshire Coalfield

It is in the county of Flintshire and extends from the Point of Ayr in the north, along the Dee Estuary through Connah's Quay to Caergwrle in the south.

[1] A small part extends onto the Wirral i.e. English coast of the estuary at Neston, Cheshire which was the site of a coalmine for a period.

The coal-bearing strata continue southwards of Caergwrle as the Denbighshire Coalfield.

The Chwarelau Seam which appears only in the north actually occurs within the underlying Millstone Grit sequence rather than the Coal Measures proper.

The seams are listed stratigraphically with the uppermost (youngest) at the head of the list and the lowermost (oldest) at the foot.