Geology

The National Trust is responsible for many geological sites, including more than 200 Sites of Special Scientific Interest (SSSIs).

We have now produced two policies: one an overarching geological policy and the other a policy on collecting geological materials (fossils, rocks and minerals).

These policies are an attempt to acknowledge our magnificent geological resource while setting out our position and approach to its promotion and conservation. We wish to work more closely with local geological groups and individuals to help us do this.

Download our policies:

Geological policy (PDF / 132 KB)
Geological collecting policy (PDF / 126 KB)

Brimham Rocks, North Yorkshire
© NTPL / Joe Cornish

There is a whole range of geological features that can be seen at a variety of different National Trust properties.

Below are tables listing some of our best geological sites to visit in different areas of the British Isles:

ENGLAND	KEY FEATURES
Brimham Rocks North Yorkshire OS Grid Ref: SE210650	• Series of millstone grit tors • Significant for the study of past and present weathering processes and landscape evolution
Cheddar Cliffs Somerset OS Grid Ref: ST468543	• Britain's largest gorge • Country’s best known limestone feature • Has been forming and changing for over 2 million years • Caves
Chyngton Farm East Sussex OS Grid Ref: TQ540970	• Fossils
Crickley Hill Gloucestershire OS Grid Ref: SO930165	• Key Jurassic locality because of exposed limestone • Best sections of pea grit and overlying coral bed in the Cotswolds
Golden Cap Estate Dorset OS Grid Ref: SY400920	• The richest source of Lower Jurassic reptiles, fish and insects anywhere in the world. • Also important for ammonites and many other invertebrate groups • Many of the fossils are extraordinarily well preserved
Hadrian’s Wall Northumbria OS Grid Ref: NY790688	• Exposures of the Whin Sill (hard, tough, dark coloured rock of igneous origin) • Outcrops of limestone and sandstone strata
Leas and Marsden Rock Tyne and Wear OS Grid Ref: NZ388665	• Magnesian limestone cliffs • Wavecut foreshore platforms • Fossils
Malham Tarn Estate North Yorkshire OS Grid Ref: SD890660	• Nationally important cave systems • Limestone pavement
North Norfolk Coast Norfolk OS Grid Ref: TG086441	• Shingle banks
Orford Ness Suffolk OS Grid Ref: TM445485	• The largest vegetated shingle spit in Europe • One of 3 major shingle landforms in the British Isles • Complex shingle ridges deposited over a long period of time • Occasional occurrence of an extinct shellfish (Terrabratula maxima) the largest one that ever lived.
Penrose Estate Cornwall OS Grid Ref: SW645250	• Intrusive igneous rock • Complex Variscan structures (mountain belt evolution during Paleozoic times). • Many small high-level intrusive greenstone bodies
Robin Hood’s Bay North Yorkshire OS Grid Ref: NZ980025	• Lots of fossils especially of plants (63 species recorded 1985)
Wasdale Cumbria OS Grid Ref: NY150080	• One of the best and most famous screes (mass of boulders and broken rocks forming a slope) in Britain
West Wight Isle of Wight OS Grid Ref: SZ350858	• Steep coastal slopes subject to slipping and erosion • Deep ravines (‘chines’) • Source of numerous dinosaur and other reptile remains • Fossilised plants have also been found

WALES	KEY FEATURES
Cadair Gwynedd, Wales OS Grid Ref: SH720160	• Volcanic rocks •Important for glacial and periglacial landforms • Contains Cwm Cau which has been described as the finest cirque in Britain • Tal-y-llyn shows good examples of stratified screes
Dolaucothi Estate Carmarthenshire, Wales OS Grid Ref: SN660400<sty sys-align-left>	• Only known British example of Roman gold mining • Presence of gold and other minerals • First recorded locality of cookeite (lithium-aluminium-hydroxy-silicate) a rare mineral
Gower Peninsula Swansea, Wales OS Grid Ref: SS383878	• Steep cliffs rising up to 70m from sea level • Wave cut platforms (raised beaches – indicative of changing sea level and climate change) • Long Hole Cave • Ice age deposits below the floor • Bones of various animals have been found, some now extinct and some no longer found in Britain • Flint tools also found from earliest humans (30,000 to 100,000 years ago)
Hafod y Llan Snowdonia Gwynedd, Wales OS Grid Ref: SH700600	• Has some of the world’s oldest rocks • The landscape has been formed by glaciers in the Great Ice Age (u-shaped and hanging valleys, erratic boulders, cirques, moraines and glacial lakes)

NORTHERN IRELAND	KEY FEATURES
Giant’s Causeway County Antrim, Northern Ireland OS Grid Ref: C952452	• Northern Ireland’s most renowned geological locality • Igneous rocks • Past volcanic activity • Formation of regular basalt columns • Cliffs and screes surrounding the Causeway are some of the best sites in NI for zeolite minerals (natural volcanic minerals based on silica and aluminium)

Giant's Causeway - a geological phenomenon renowned for its polygonal columns of layered basalt, caused by a volcanic eruption 60 million years ago