Geology of the Durham Coast

From where it rises, approximately 10km from the county's coastline, the Magnesian Limestone Plateau of East Durham drops gently eastwards ending abruptly at cliffs as it meets the sea. Laid down during the Permian period, 240 million years ago, it is formed from the remains of the skeletal structures and shells of countless animals that built reefs or settled on the bed of a tropical sea. The line of the cliffs is interrupted at intervals by denes and gills - Valleys cut deep into the limestone by watercourses.

Magnesian Limestone rarely appears close to the surface in Britain and it is even rarer for such outcrops to exist near the sea. These factors lead to a very rare set of conditions for both plants and animals. The north east of England boasts most of this important wildlife habitat.

Earlier in geological history the area destined to become County Durham was covered in forest and swamps. Subsequent burial of the forests led to the extensive coal deposits that now lie beneath the limestone plateau.

The existing important habitats are to be protected at all times during restoration works and in addition large areas of valuable habitat along the cliff-tops are being restored by replacing arable land with limestone grassland. This will create a retreat zone into which the existing wildlife communities can move as the cliffs are eroded naturally by the action of the sea.

The prossess of re-creating magnesian limestone grassland is set out in The Durham Coast Habitat Creation Strategy and is generally the same process for reclaiming colliery sites and former agricultural land.