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!