Geology Along the South West Coast Path

A simple general guide produced by ChatGPT

1. Somerset & Exmoor (Minehead → Combe Martin)

  • Rocks: Devonian sandstones, mudstones, and slates.
  • Features: High cliffs cut into ancient river and delta deposits.
  • Highlight: The Hangman Grits (hard sandstones) form towering cliffs like Great Hangman, the highest point on the Path (318 m).

2. North Devon (Combe Martin → Hartland Quay)

  • Rocks: Devonian sandstones, slates, and shales.
  • Processes: Intense folding during the Variscan Orogeny created dramatic, contorted strata.
  • Highlights:
    • Ilfracombe Slates – thinly layered and easily weathered.
    • Morte Slates – give rugged headlands.
    • Hartland Quay – spectacular folded and faulted cliffs.

3. North Cornwall (Hartland Quay → Padstow)

  • Rocks: Upper Carboniferous sandstones and shales.
  • Features: Some of the best folded cliffs in Britain.
  • Highlights:
    • Bude Formation – rhythmic alternations of sandstone and shale, creating striking chevron folds (Millook Haven).
    • Tintagel Slate – famous for medieval quarrying, used in roofing.
    • Quarries & Ports – slate exported from places like Tintagel, Trebarwith Strand, and Port William.

4. Mid & West Cornwall (Padstow → Land’s End)

  • Rocks: Dominated by Cornubian granites (Bodmin Moor, Carnmenellis, Penwith).
  • Features:
    • Weathered tors and moorland.
    • Mineralised veins of tin and copper → rich mining heritage.
  • Highlights:
    • St Agnes Head – mineral-stained cliffs (iron and copper oxides).
    • Botallack & Levant Mines – engine houses perched above the sea.
    • Land’s End Granite – massive cliffs resistant to erosion.

5. South Cornwall (Land’s End → Plymouth)

  • Rocks: A mix — granite, Devonian slates, and volcanic rocks.
  • Features: Sheltered rias (drowned river valleys) like the Fal and Helford.
  • Highlights:
    • Lizard Peninsula – unique! Formed of ophiolite rocks (serpentine, gabbro, basalt), once part of ocean crust pushed up onto land. This is one of Britain’s geological jewels.
    • Roseland & Fowey – drowned valleys shaped after the last Ice Age.

6. South Devon (Plymouth → Exmouth)

  • Rocks: Devonian limestones and slates, with Permian sandstones in the east.
  • Features:
    • Limestone cliffs at Plymouth Sound and Torbay.
    • Red cliffs east of Torbay → Permian desert sandstones.
  • Highlights:
    • Hope’s Nose, Torquay – fossil-rich limestone headland.
    • Dawlish & Teignmouth – striking red sandstone cliffs.

7. East Devon & Dorset (Exmouth → Poole Harbour)

  • Rocks: Triassic, Jurassic, and Cretaceous sequences.
  • Features: This is the Jurassic Coast World Heritage Site.
  • Highlights:
    • Exmouth & Sidmouth – red Triassic desert rocks.
    • Lyme Regis – world-famous Jurassic fossil beds (ichthyosaurs, ammonites).
    • Chesil Beach & Portland – shingle barrier and Portland limestone quarries.
    • Durdle Door & Lulworth Cove – iconic coastal landforms from folded Jurassic strata.

✅ Summary

Dorset: Younger Mesozoic rocks → fossil coasts and world-class landforms.

West (Somerset → Cornwall): Devonian/Carboniferous rocks, folded and faulted.

Cornish core: Granite intrusions + mining geology.

South Cornwall & Devon: Mixed slates, limestones, and Permian desert sandstones.