Portland’s Geology

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

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.

Quarry Wildlife

Many of the disused quarries on Portland are protected, being sites of Special Scientific Interest.

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!

Limestone Grassland

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.

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.

Blacknor Fort

Blacknor Fort was originally built around 1902 and the stronghold was re-equipped during the World Wars. During WW2 on the night of the 27th April 1944, the gunners could only watch as Nazi E-boats attacked landing craft full of American soldiers on exercise in Lyme Bay. They were ordered not to fire for fear of hitting the men in the water. The Slapton Sands Massacre, as it became known, saw more than 600 American soldiers and seamen drowned by the end of the night, many pulled down by the sheer weight of their own equipment.