Great Southwell Landslip

[1] Cracks and gullies within the cliffs had allowed rain water to percolate through the layers of Purbeck Beds, Portland Limestone and Portland Sand to the underlying impermeable Kimmeridge Clay, and the accumulation of water had weakened the structure between the strata.

Because the island tilts to the south and the east, this allowed the overlying strata to slip.

[1][2] At St Andrew's Church a large section of the graveyard slipped down the cliff.

The cliff face has been subject to extensive quarrying, and subsequent smaller landslips have tilted huge masses of rocks at odd angles.

Along this part of the coastline much of Portland's raw sewage once poured into the sea from an exposed pipe.