Dorset is world-renowned for its geological diversity, as exemplified by UNESCO World Heritage Coast (‘Jurassic Coast‘) status.

As first outlined in the early 1800s by William ‘Strata’ Smith, geology underpins the varied landscape of Dorset. Ridges and uplands are formed from resilient sandstone, limestone and chalk (a pure form of limestone) with valleys and lowlands formed from less resilient sands and clays. Although our modern geological understanding is more detailed and complex, it has broadly confirmed William Smith’s pioneering work. Many geological names remain the same as those used by William Smith, often based on older quarrying terms.

christchurch_tauntonGeological section of Dorset by William ‘Strata’ Smith 1819. Zoom in for more detail. [View/Download]

William Smith 1819Current Geological NomenclatureBuilding Stone
1London ClayBarton GroupBecton Sand Formation 
Chama Sand Formation 
Barton Clay FormationHengistbury Head Ironstone
Bracklesham GroupBosconbe Sand Formation 
Branksome Sand FormationHeathstone
Poole FormationHeathstone and Sarsens
Thames GroupLondon Clay FormationLytchett Matravers Sandstone
2Clay, Brickearth, Sand and Gravel Harwich FormationWarmwell Farm Heathstone
3CragLambeth GroupReading FormationWest Park Farm Heathstone
4SandUpnor FormationSarsens
5ChalkUpper ChalkWhite Chalk SubgroupPortsdown Chalk FormationFlint and Clunch
Culver Chalk FormationSpetisbury Chalk Member
Tarrant Chalk Member
Newhaven Chalk Formation
Seaford Chalk Formation
Lewes Nodular Chalk Formation
New Pit Chalk Formation
Holywell Nodular Chalk Formation
Lower ChalkGrey Chalk SubgroupBeer Head Limestone FormationZig Zag Chalk FormationBeer Stone, Clunch
West Melbury Marly Chalk FormationMelbury Sandstone
6GreensandSelborne GroupUpper Greensand FormationBindon Sandstone and Whitecliff Chert Members, Eggardon Grit and Boyne Hollow Chert MembersBindon Sandstone, Chert
Foxmould Member, Shaftesbury Sandstone and Cann Sand MembersShaftesbury Stone, ‘Cowstones’
7Golt Brickearth Gault Formation 
8SandLower Greensand Group 
Wealden GroupCourse Quartz Grit
9Purbeck StonePurbeck GroupDurlston FormationPeveril Point MemberPurbeck Marble, and Burr
Stair Hole MemberLaning Vein,
Freestone Vein, and Downs Vein
Lulworth FormationWorbarrow Tout MemberNew Vein
Ridgeway MemberCypris Freestone
Mupe Member
Portland RockPortland GroupPortland Stone FormationPortland Freestone MemberPortland Freestone
Portland Chert MemberChert
10SandPortland Sand FormationGad Cliff Member 
Pondfield Member 
Corton Hill Member‘Exogyra Bed’ White Cementstone
Black Nore Member 
11Oaktree ClayKimmeridge Clay FormationUpper Kimmeridge ClayDolomitic Limestone
Lower Kimmeridge ClayDolomitic Limestone
12Coral Rag and Pisolite or OoliteCorallian GroupAbbotsbury Ironstone FormationIronstone
Sandsfoot Formation 
Clavellata FormationClavellata Stone
Osmington Oolite FormationStour FormationAbbotsbury, Todber, Marnhull, Sturminster and Cucklington Stone
13Sand Redcliff FormationHazelbury Bryan Formation 
14Clunch Clay and ShaleOxford Clay FormationWeymouth Member 
Stewartby Member 
Peterborough Member 
15Kellaways StoneKellaways Formation 
16CornbrashGreat Oolite GroupCornbrash FormationUpper Cornbrash MemberCornbrash
Lower Cornbrash Member
17Clay & SandForest Marble FormationForest Marble Sandstone
18Forest Marble Forest Marble Limestone
19Clay over the Upper OoliteFrome Clay Formation 
20Upper Oolite Wattonensis Beds Member 
 ClayFuller’s Earth FormationUpper Fuller’s Earth Member 
21Fuller’s Earth Rock Member Fuller’s Earth Rock MemberFuller’s Earth Rock
 Clay Lower Fuller’s Earth Member 
22Under OoliteInferior Oolite GroupBurton, Beaminster, Sherborne and Hadspen Stone
23Sand & SandstoneLias GroupBridport Sand FormationHam Hill Limestone MemberHam Hill Stone
Down Cliff Clay Member 
24Marlstone Beacon Limestone FormationEype Mouth Limestone MemberSymondsbury and Yeovil Stone
Marlstone Member
25Blue Marl Dyrham FormationThorncombe Sand MemberDoggers
Down Cliff Sand Member 
Eype Clay Member 
 Charmouth Mudstone Formation Green Ammonite Member 
Belemnite Marl MemberBelemnite Stone
Black Ven Marl Member 
Shales-with-Beef Member 
26LiasBlue Lias Blue Lias FormationBlue Lias
27White LiasPenarth GroupLilstock FormationLangport MemberWhite Lias
Cotham Member 
Westbury Formation 
28Red MarlMercia Mudstone Group 
Dorset Geology: showing William Smith’s names and colour scheme, modern geological nomenclature (Group, Formation and Member), usage as building stone. Stones in bold are most commonly used in dry stone walls, though others may have localised use.


This geodiversity is reflected in the varied and localised use of stone in dry stone walls and other buildings. Every town, village, hamlet, estate and farm has typically been built from stone from local quarries. Even places only a few miles apart can be built from very different stone that defines their particular character, atmosphere and charm. For more information see Jo Thomas (2008) Dorset Stone, Dovecote Press, Dorset or the Dorset Building Stone website.

In and around the county a wide range of building stone has been used: Blue Lias (Lyme Regis, South Somerset), Beacon Limestone (Symondsbury, Yeovil), Inferior Oolite (Burton Bradstock, Mapperton, Beaminster, Sherborne), Fuller’s Earth Rock (Thornford), Forest Marble (Bridport, West Bexington, Langton Herring, Yetminster, Lillington, Longburton), Corallian Limestone (Abbotsbury, Wyke Regis, Marnhull, Todber), Portland and Purbeck (Isles of Portland and Purbeck), Chert (Morcombelake), Upper Greensand (Shaftesbury), Chalk and Flint (Frome, Cerne and Piddle valleys), Heathstone (Lytchett Matravers). For further geological detail, see our interactive map.

Some prestigious buildings, particularly churches, have used stone from further afield, even ‘imported’ from outside Dorset. For example many church door and window frames use Ham Hill Stone, from just over the border in South Somerset. Such ‘exotic’ stone is rarely found in field walls, though there are exceptions. For example walls around Cerne Abbas may contain Purbeck Stone ‘recycled’ from the ruined Abbey and originally from quarries on the South Dorset Ridgeway.

Dorset is pockmarked with old quarry workings. Many are identified on First and Second Edition OS Maps and are often visible as scars on high resolution LiDAR Digital Terrain Models (See interactive map). The Dorset Area of Outstanding Natural Beauty is rooted in an earlier industrial landscape. However, there are now rather few working quarries which can make sourcing appropriate material for dry stone walling, and other geoconservation projects, rather difficult.

It is hoped the following resources may help you source the ‘right’ stone for a particular location. It is well worth making the effort.