The cliffs here change dramatically from being upright to land slipped. This is the most southerly extent of the Great Southwell landslip, an event that affected 1½ miles (2 km) of coastline between Freshwater Bay and Durdle Pier in 1734.
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The Great Southwell Landslide
The Great Southwell Landslip on the Isle of Portland is Britains, second largest recorded landslide
In 2003 a section of dinosaur footprints was found in quarried blocks waiting to be processed in a Bath and West Stone quarry at Southwell, Portland. The tracks are thought to be that of an Iguanodon that roamed here around the same time as the fossil forests were flooded. The problem now lies in trying to piece the tracks together, as the blocks are scattered about like a giant Jurassic jigsaw puzzle.
Coastal Features: Portland’s Geology, The Great Southwell landslip
Portland’s dramatic landscape is shaped by the stresses placed upon it by the Weymouth Anticline, a huge fold thrown up during the mountain building period that created the Alps when the continents of Africa and Europe collided around 30 million years ago. The uplifting process tilted the Isle and created cracks and gullies that shape the towering cliffs to the west and the boulder strewn landslides in the east.
The uplifting of Portland has tilted the Isle so the cliffs on the west side are higher than those on the east.
This means the western cliffs erode in a completely different way from those on the opposite side.
The cliffs of East Weare are subject to large sprawling landslides, such as the Great Southwell Landslip, where the cliffs have fallen “down dip”, while the cliffs on the western side of the Isle tend to topple into the sea where they have fallen “up dip”.
All the falls and slides on either side of the island are parallel, following the cracks and fissures created
The Great Southwell landslip
The Great Southwell Landslip is Britain’s second largest recorded historical landslide. The event occurred in 1734, between Durdle Pier and Freshwater Bay, a distance of 1 1/2 miles (2 km). The cracks and gullies within the cliffs of Portland allow rain water to easily percolate down through the layers of Purbeck Beds, Portland Limestone and Portland Sand to the underlying impermeable Kimmeridge Clay below. Because the Isle tilts to the south and the east, caused by the uplifting process, the water collects at the lowest points.
Coastal Visitor Centre
Portland Bill Visitor Centre
Town/Village or Area:
Tourist Info Centres
in this Area: Limestone Grassland, Butterflies and Moths, Bunnies
It is deemed unlucky to say “Rabbits” on Portland as they were often thought to be responsible for creating accidents by their digging undermining the stability of quarry workings. But despite being unpopular, their numbers thrive amongst the Great Southwell Landslip and the numerous disused quarries on the Isle.
Butterflies and Moths
Portland’s disused quarries, grassy wildflower meadows and landslips are a good place to see butterflies and moths. Of Britain’s 2,500 species of moth, over 800 have been recorded on Portland. In addition to moths, over half of Britain’s 57 different species of Butterfly have also been found here. While many live out their short lives on Portland, not all are permanent residents. Some are migrants, heading to our country from the continent to breed, while others are just incidental visitors, having been blown out into the English Channel until they reach the landfall of Portland - some have even been carried all the way from Africa!
The limestone habitat of Portland’s grasslands creates colourful summer meadows full of wildflowers and butterflies. The dandelions and plantains that grow here are food for around 20 species of caterpillar.
Interest: The Portland Estate, Modern Quarry Techniques
The Portland Estate
Around 250 hectares of land on Portland are currently managed by the Crown Estate. This is part of the “Royal Manor of Portland” which has been in the of the Crown’s possession since Saxon times.
Around 160 hectares of the Estate is common land, which was traditionally used by the locals for the grazing of their animals and the removal of stone. The land is supervised by one of the last surviving Courts Leet in Britain, having been in operation since 800AD. Portland’s Court Leet meets on the third Friday of November every year, when matters involving income derived from fines and rents for the encroachment onto common land can be administered.
Modern Quarry Techniques
Modern quarrying techniques include the use of diamond cutting technology to saw the Portland Stone into blocks. These blocks are then transported to factories where the stone is worked into its end product. Portland stone is used a great deal in building restoration and is easy to carve in any direction due to its ball bearing like structure.
Its resistance to weathering makes it ideal to use.