User:Huligan0/The Pinnacles, Dorset

The Pinnacles are two chalk formations, including a stack and a stump, located near Handfast Point, on the Isle of Purbeck in Dorset, southern England.

Location
The Pinnacles lie directly east of Studland, about 200 Metres south of Old Harry Rocks and about 4 kilometres northeast of Swanage. The chalk headlands of the Ballard Downs are owned by the National Trust. The rocks can be viewed from the Dorset section of the South West Coastal Path.

Geography
The Jurassic Coast stretches over a distance of 153 km, from Orcombe Point near Exmouth, in the west, to just beyond the great chalk headland of Ballard Down and Old Harry Rocks here in the east. The coastal exposures along the coastline comprise a continuous sequence of Triassic, Jurassic and Cretaceous rock formations spanning approximately 185 million years of the Earth's history. The rock layers along the Jurassic Coast are tilted towards the east. The oldest part of the coast is found at its west end, while progressively younger rocks form the cliffs here to the east. Old Harry Rocks mark the most easterly point of the Jurassic Coast, a UNESCO World Heritage Site.

The downlands of Ballard Down are formed of chalk with some bands of flint, and were formed approximately 65 million years ago. The bands of stone have been gradually eroded over the centuries, some of the earlier stacks having fallen while new ones have been formed by the breaching of narrow isthmuses. Across the water to the east the Needles on the Isle of Wight are usually visible. These are also part of the same chalk band and only a few thousand years ago were connected to Ballard Down.

To form the stacks, the sea gradually eroded along the joints and bedding planes where the softer chalk meets harder bedrock of the rock formations to create a cave. This eventually eroded right through to create an arch. The arch subsequently collapsed to leave the stacks calles The Pinnacles.