The Pembroke Limestone Group is a stratigraphic unit of Courceyan to Brigantian age (Early Carboniferous) found in southern Wales and northern Somerset.

[1] These carbonate rocks developed in platform and ramp environments and are up to 1025m thick in places.

Likewise the Linney Head to Pen-y-Holt sequence is replaced by a tripartite sequence with the Gully Oolite at its base, unconformably overlain by the Caswell Bay Mudstone Formation and topped with the High Tor Limestone Formation.

To the east of the Severn, the Pembroke Limestone within the English part of the basin is initiated by an undivided Black Rock Subgroup, overlain except in the Mendip Hills by the Gully Oolite once again.

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