Barclay, W.J., Browne, M.A.E., McMillan, A.A., Pickett, E.A., Stone, P. & Wilby, P.R. 2005. The Old Red Sandstone of Great Britain. Geological Conservation Review Series No. 31, JNCC, Peterborough. The original source material for these web pages has been made available by the JNCC under the Open Government Licence 3.0. Full details in the JNCC Open Data Policy
Tables
| Site | Age | Selection criteria |
| Orcadian Basin | ||
| Easter Rova Head | Mid-Devonian | Spectacular sea-cliff exposures of conglomerates. |
| Footabrough to Wick of Watsness | Mid-Devonian | Continuous sea-cliff exposures of Walls Formation. |
| The Cletts, Exnaboe | Mid-Devonian | Continuous sea-cliff exposures of cyclic lacustrine, fluvial and aeolian facies of the Brindister Flagstone Formation. Also a fossil fish GCR site. |
| Melby: Matta Taing to Lang Rigg (P) | Mid-Devonian | Fossil fish GCR site. Spectacular sea-cliff and foreshore exposures of lacustrine Melby Formation. |
| South Stromness Coast Section | Mid-Devonian | Best section in Orkney through the Caithness Flagstone Group. |
| Taracliff Bay to Newark Bay | Mid-Devonian | Thickest, best-exposed section of the Eday Group. |
| Greenan Nev Coast, Eday | Mid-Devonian | Best section through the Eday Marl Formation in Orkney. |
| South Fersness Bay, Eday | Mid-Devonian | Well-exposed, accessible section of the Eday Group. |
| Yesnaby and Gaulton Coast Section | Early Devonian | Superb sea-cliff sections of the Yesnaby Sandstone Group, including unique aeolian facies. Also sections in the Lower Stromness Flagstone Formation containing the best stromatolites in the Orcadian Basin. |
| Old Man of Hoy Coast | Late Devonian | Spectacular sea cliffs of the Hoy Sandstone Formation, including the lloy Volcanic Member. |
| Bay of Berstane (P) | Mid-Devonian | Unique onshore evidence of marine-influenced deposition in the Middle Devonian Eday Marl Formation. |
| Red Point | Mid-Devonian | Spectacular lake-margin deposits and basement-cover topography. |
| Pennyland (Thurso–Scrabster) | Mid-Devonian | Well-exposed lacustrine cycles of the Orcadian lake (Upper Caithness Flagstone Group). Also a fossil fish GCR site. |
| John o'Groats (P) | Mid-Devonian | Fossil fish GCR site. Type locality of John o'Groats Sandstone Group. |
| Wick Quarries | Mid-Devonian | Spectacular exposures of fish-bearing lake deposits and shrinkage cracks in the Lower Caithness Flagstone Group in an otherwise poorly exposed part of the Orcadian Basin. |
| Achanarras Quarry (P) | Mid-Devonian | Fossil fish GCR site, the richest locality in Great Britain. Type locality of Achanarras Limestone Member (Fish Bed), of importance regionally as a marker horizon between the Lower Caithness Flagstone Group and Upper Caithness Flagstone Group. |
| Sarclet (P) | Early Devonian | Sea-cliff sections in the Lower Devonian Sarclet Group. |
| Tarbat Ness | Mid-Devonian and Late Devonian | Complete section of the Balnagown Group and of the apparently conformable junction with the Strath Rory Group. |
| Loch Duntelchaig (Dun Chia Hill) | Mid-Devonian | Dramatic exposure of Middle Old Red Sandstone conglomerates resting unconformably on Dalradian metasedimentary rocks and late Caledonian granites in the south-west of the Orcadian Basin. |
| Tynet Burn (P) | Mid-Devonian | Fossil fish GCR site. Classic fossil fish locality yielding whole, well-preserved specimens, and important evidence on the nature of the southern margin of the Orcadian Basin at the time of maximum (Achanarras) lake extent. |
| Den of Findon, Gamrie Bay and New Aberdour (P) | Mid-Devonian (also Early Devonian) | Fossil fish GCR site, with superb coast sections at Gamrie Bay, Pennan (Lower ORS–Middle ORS) unconformity), New Aberdour and Quarry Haven. |
| Rhynie (P) | Early Devonian | Fossil plant GCR site. World renowned floral and arthropod lagerstätte. Exceptional preservation in a hydrothermal spring deposit. |
| Midland Valley of Scotland and adjacent areas | ||
| The Toutties (P) | Mid-Silurian | Fossil fish GCR site. Oldest (Mid-Silurian) Old Red Sandstone facies in Scotland containing fish and important arthropod fauna. |
| Dunnottar Coast Section (P) | Mid-Silurian–Early Devonian | Magnificent exposures in dramatic sea cliffs of conglomerates and sandstones. |
| Crawton Bay | Late Silurian–Early Devonian | Fine coastal sections of conglomerates and volcanics. Also a Caledonian igneous rocks GCR site |
| North Esk River | late Early Devonian | Best sections of the Strathmore Group |
| Milton Ness (P) | Late Devonian–Early Carboniferous | Sea cliffs exposing one of the best sections of mature calcrete development in Scotland in the Kinnesswood Formation. |
| Aberlemno Quarry (P) | Early Devonian | Fossil fish and Palaeozoic palaeobotany GCR site. Also important for arthropod fossils. Important for Dundee Flagstone and Scone Sandstone formations. |
| Tillywhandland Quarry (P) | Early Devonian | Fossil fish GCR site. Unique lacustrine facies in the Midland Valley of Scotland in the Dundee Flagstone Formation containing fish, arthropods and trace fossils. |
| Whiting Ness | Early and Late Devonian | Sea cliffs exposing Early Devonian sandstones unconformably overlain by Late Devonian sandstones, the units being separated by a spectacular unconformity. |
| Tay Bank | Early Devonian | Type locality of the Campsie Limestone Member, including the Stanley Limestone, representing mature calcrete development and providing an important stratigraphical marker horizon. |
| Glen Vale (P) | Late Devonian | Important sandstones (the Knox Pulpit Sandstone Formation) of aeolian origin. |
| Wolfs Hole Quarry (P) | Early Devonian | Fossil fish GCR site exposing the highest lava on the southern side of the Strathmore Basin. |
| Auchensail Quarry (P) | Early Devonian | Fossil plant GCR site yielding a well-preserved assemblage of land plants in the Teith Sandstone Formation. |
| Siccar Point to Hawk's Heugh (E) | Late Devonian-Early Carboniferous | Classic section at Siccar Point (Hutton's Unconformity). Fossil fish GCR site at Hawk's Heugh. Proposed extension to include the intervening superb sections of fluvial and ?aeolian sandstones at Pease Bay. |
| Largs Coast, Ayrshire | Late Devonian | Important coastal exposures in sandstones illustrating fluvial, braided river sandbody morphologies. |
| North Newton Shore, Arran | Late Devonian | One of the three classic Old Red Sandstone unconformities recognized by James Hutton. |
| Southern Scotland and the Lake District | ||
| Palmers Hill Rail Cutting | Late Devonian | Exposures of calcrete in the Scottish Border Basin. |
| Pooley Bridge | Early Devonian | Best section of Old Red Sandstone facies conglomerates in north-west England. |
| Anglo-Welsh Basin | ||
| Porth-y-Mor | Early Devonian | One of the best, most accessible Old Red Sandstone sections in the Anglo-Welsh Basin. |
| Devil's Hole (P) | Late Silurian-Early Devonian | Historically important fossil fish GCR site, with important 'Downtonian'–'Dittonian' boundary exposure. |
| Oak Dingle, Tugford (P) | Early Devonian | Fossil fish GCR site with well-documented sedimentological analysis. |
| The Scar | Late Silurian | Good inland exposure of the Raglan Mudstone Formation. |
| Cusop Dingle (P) | Late Silurian-Early Devonian | Best, most complete inland section through topmost Přídolí and lowermost Devonian strata. |
| Sawdde Gorge (E) | Late Silurian-Early Devonian | Proposed extension of GCR site to include higher Přídolí and basal Devonian strata. |
| Pantymaes Quarry (P) | Early Devonian | Excellent exposure of Lochkovian channel sandstones and floodplain mudstone facies, internationally known for its arthropod trackways. |
| Heol Senni Quarry | Early Devonian | GCR fossil fish site. Also representative of the Senni Formation. |
| Caeras Quarry | Early Devonian | Best exposure of local pebbly facies in the Brownstones Formation. |
| Craig-y-Fro Quarry (P) | Early Devonian | Classic fossil plant GCR site. Also Important for exposure of the Senni Formation. |
| Abercriban Quarries | Late Devonian-Early Carboniferous | Type locality of the Grey Grits Formation. |
| Mon y Waen (P) | Late Devonian | Potential fossil fish GCR site. Also important for exposure of the Plateau Beds Formation. |
| Duffryn Crawnon (P) | Late Devonian | Type locality of the Plateau Beds Formation, induding possible aeolian facies. |
| Craig-y-cwm (P) | Late Devonian-Early Carboniferous | Representative section of the Quartz Conglomerate Group. |
| Ross-on-Wye, Royal Hotel | Early Devonian | Excellent, well-documented, accessible section of the Brownstones Formation. |
| Wilderness (Land Grove) Quarry | Early Devonian | Fossil fish GCR site with superb exposure of the lowermost strata of the Brownstones Formation. |
| Lydney | Late Silurian-Early Devonian | Fossil fish GCR site with good section of the Psammosteus Limestone horizon. |
| Albion Sands and Gateholm Island (P) | Late Silurian-Early Devonian | Magnificent sea-cliff and foreshore exposures of Wenlock marine strata and the overlying Old Red Sandstone. |
| Little Castle Head (P) | Late Silurian-Early Devonian | Reference section of the Přídolí Sandy Haven Formation and of the Townsend Tuff Bed. |
| West Angle Bay (North) | Late Silurian-Early Carboniferous | Continuous section of the entire Old Red Sandstone succession and of the underlying and overlying strata. |
| Freshwater West (P) | Late Silurian-Early Carboniferous | Superb, accessible dip section exposing the entire Old Red Sandstone succession. |
| Freshwater East–Skrinkle Haven ('Tenby Cliffs') | Late Silurian-Early Carboniferous | Excellent strike section of the entire Old Red Sandstone succession. |
| Llansteffan | Late Silurian-Early Devonian | Superb exposures of stacked carbonate palaeosols of the Chapel Point Calcretes Member (Psammosteus Limestone). |
| Portishead | Early and Late Devonian | Best section of the Old Red Sandstone succession east of Severn Estuary. |
| Glenthorne | Mid-Devonian | Best section of Old Red Sandstone facies south of the Bristol Channel. |
| P Potential site (most of these sites are confirmed GCR sites for their palaeontology)
E Proposed extension to site |
| Site | Stratigraphy | Criterion | Treatment in this volume Full description FD Summary description SD Not described ND |
| Orcadian Basin | |||
| Westerdale Quarry | Mid-Devonian; Eifelian | One of oldest fish-bearing horizons in Orcadian Basin; complete specimens | ND |
| Achanarras Quarry | Mid-Devonian; Eifelian–Givetian boundary | Richest Old Red Sandstone fish site in Britain | FD |
| Cruaday Quarry | Mid-Devonian; Eifelian–Givetian boundary* | Best Old Red Sandstone fish site in Orkney | ND |
| Black Park, Edderton | Mid-Devonian; Eifelian–Givetian boundary* | Fish well preserved in three dimensions | ND |
| Den of Findon, Gamrie | Mid-Devonian; Eifelian–Givetian boundary* | Prolific fish fauna | SD |
| Tynet Burn, Elgin | Mid-Devonian* | Rich fish fauna and historically important | FD |
| Melby | Mid-Devonian; Eifelian–Givetian boundary* | Northernmost occurrence of Achanarras horizon | FD |
| Papa Stour | Mid-Devonian; Eifelian–Givetian boundary* | Fish in sedimentary rocks in predominantly volcanic sequence | ND |
| Dipple Brae | Mid-Devonian | Fish fauna younger than that of the Achanarras horizon | ND |
| Spinal Quarry | Mid-Devonian | Rare fish fauna, including only Mid-Devonian cephalaspid | ND |
| Banniskirk Quarry | Mid-Devonian | First ORS site to yield fishes | ND |
| Holborn Head Quarry | Mid-Devonian; mid-Givetian | 10–11 fish species, including Osteolepis panderi | ND |
| Weydale Quarry | Mid-Devonian | Well-preserved Osteolepis panderi and Dipterus valenciennesi | ND |
| Pennyland | Mid-Devonian; Givetian | Many fish specimens from several fish-bearing horizons | FD |
| John o'Groats | Mid-Devonian; late Givetian | Youngest fish fauna in Caithness | SD |
| The Cletts, Exnaboe | Mid-Devonian; late Givetian | Northernmost late Givetian fish site | FD |
| Sumburgh Head | Late Mid-Devonian; late Givetian | Possibly youngest fish fauna of the Orcadian Basin | ND |
| Midland Valley of Scotland | |||
| The Toutties | Late Wenlock | Oldest Old Red Sandstone facies rocks in Scotland; unique fish fauna | FD |
| Tillywhandland Quarry | Early Devonian | One of best Early Devonian fish sites in Scotland | FD |
| Aberlemno Quarry | Early Devonian | Best surviving of the famous Turin Hill fish sites; also a fossil plant GCR site ( |
FD |
| Wolf's Hole Quarry | Early Devonian | Unique pteraspid fish fauna | FD |
| Whitehouse Den | Early Devonian | Fossil acanthodian fish | ND |
| Grampian Highlands | |||
| Ardmore-Gallanach | Late Silurian-Early Devonian | Unique early fish fauna in sediments associated with Lorne lavas | ND |
| Bogmore, Muckle Burn | Earliest Late Devonian (Frasnian) | Diverse fish fauna with over 15 species | ND |
| Scaat Craig | Late Devonian | Diverse late Devonian fish fauna and a distinctive tetrapod | ND |
| * Achannaras Fish Bed horizon | |||
| Southern Uplands | |||
| Oxendean Burn | Late Devonian | Abundant fragments of Bothriolepis | ND |
| Hawk's Heugh | Late Devonian | Only British occurrence of Remigolepis | |
| Anglo-Welsh Basin | |||
| Ludford Lane and Ludford Corner | Silurian; Přídolí | Internationally renowned for rich fish fauna; see also |
FD
ND |
| Ledbury cutting | Silurian; Přídolí | Historical site yielding complete specimens of Auchenaspis and Hemicyclaspis | ND |
| Temeside, Ludlow | Silurian: Přídolí | Historical site in Temeside Mudstone Formation yielding a rich fish fauna including Hemicyclaspis murchisoni | ND |
| Tite's Point (Purton Passage) | Silurian; Ludlow–Přídolí | Thelodus parvidens fish fauna, allowing correlation with Ludlow Bone Bed, and source of Cyathaspis | |
| Lydney | Late Přídolí–Early Devonian | Sequence of vertebrate faunas, including specimens of Sabrinacanthus | FD |
| Downton Castle area (network of 4 sites) | Early Přídolí | Several quarries in Downton Castle Sandstone yielding vertebrate remains | ND |
| Bradnor Hill Quarry | Late Přídolí | Late Přídolí thelodont fauna | ND |
| Devil's Hole | Přídolí–Lochkovian | Fish fauna straddling Downtonian-Dittonian boundary | SD |
| Oak Dingle, Tugford | Lochkovian (Dittonian) | Near-strike section of fish- bearing beds; earliest record of Weigeltaspis | SD |
| Cwm Mill | Lochkovian (Dittonian) | Unique preservation of complete cephalaspids, including three new species; also specimens of Rhinopteraspis crouchi | ND |
| Wayne Herbert Quarry | Lochkovian (Dittonian) | Well-preserved, diverse fish fauna | Nb |
| Besom Farm Quarry | Lochkovian (Dittonian) | Rich, diverse fish fauna, including 7 type specimens and sole occurrence of 5 of them | ND |
| Heol Senni Quarry | Lochkovian–Pragian | Only occurrence of Althaspis senniensis | FD |
| Portishead | Late Devonian | Unique fish fauna, including only British occurrence of Groenlandaspis | FD |
| Prescott Corner | Late Devonian (Frasnian) | Extensive Late Devonian fish fauna | ND |
| Mon y Waen | Late Devonian | Bothriolepis and Holoptychius in Upper Old Red Sandstone | FD |
| Site | Stratigraphy | Criterion | Treatment in this volume |
| Full description FD Summary description SD
Not described ND |
|||
| Orcadian Basin | |||
| Sloagar | Mid-Devonian; Late Givetian | Only occurrence of Svalbardia in Britain | ND |
| Bay of Skaill | Mid-Devonian | Important floral assemblage in Sandwick Fish Bed; type locality of Protopteridium thomsonii | ND |
| Rhynie | Early Devonian | Renowned Devonian palaeobotanical site; 22 species unique to this site | FD |
| Midland Valley of Scotland | |||
| Turin Hill | Early Devonian | Best example of
Zosterophyllum Zone flora in world and type locality of Cooksonia caledonica |
FD (as 'Aberlemno Quarry') |
| Ballanucater Farm | Early Devonian; Emsian | Best Emsian floral assemblage in Britain | ND |
| Auchensail Quarry | Early Devonian; Emsian | Well-preserved Emsian floral assemblage | FD |
| Anglo-Welsh Basin | |||
| Targrove Quarry | Early Devonian; Gedinnian | Most diverse rhyniophytoid plant assemblage in world | ND |
| Capel Horeb Quarry | Late Silurian; Ludfordian–Přídolí | Oldest vascular plants in world in Ludlow Series; Long Quarry Formation yielded some rhyniophytoids including Cooksonia | ND |
| Perton Lane | Late Silurian; Přídolí | Classic locality and type locality of Cooksonia | ND |
| Freshwater East | Late Silurian; Přídolí | Most diverse Silurian flora in the world | FD |
| Llanover Quarry | Early Devonian; Siegenian | Classic locality yielding one of most diverse Psilophyton Zone flora in Britain | ND |
| Craig-y-Fro Quarry | Early Devonian | Some of best preserved Devonian plants in Britain; locality second only to the Rhynie site in Britain | SD |
| Site | Stratigraphy | Criterion | Treatment in this volume |
| Full description FD Summary description SD Not described ND | |||
| Anglo-Welsh Basin | |||
| Marloes | Wenlock–Přídolí | Classic site showing early transition from marine to Old Red Sandstone facies | ND (included with report for Albion Sands and Gateholm Island) |
| Albion Sands and Gateholm Island | Ludlow–Přídolí- Lochkovian | Complete, conformable succession from Ludlow into early Devonian | SD |
| Freshwater East (South) | Wenlock–Přídolí | Wenlock marine strata overlain by Old Red Sandstone; faulted/ unconformable relationship | ND |
| Ludford Lane and Ludford Corner | Ludlow–Přídolí | Classic, internationally renowned site traditionally regarded as reference section for Silurian-Devonian boundary; earliest known land animals, early plants (see |
ND |
| Brewin's Bridge/Canal | Ludlow–Přídolí- Carboniferous | One of few sites in central England exposing marine Silurian-Old Red Sandstone junction, including Ludlow Bone Bed | ND |
| Capel Horeb Quarry | Ludlow–Přídolí | Good section of unconformity between Ludlow and Přídolí; internationally important plant site ( |
ND |
| Little Castle Head | Přídolí | Old Red Sandstone facies rocks; Townsend Tuff Bed | SD |
| Lower Wallop Quarry | Ludlow–Přídolí | Marine to Old Red Sandstone transition later here, well into Přídolí | ND |
| Site | Stratigraphy/ radiometric age | GCR selection criteria |
| Eshaness Coast | Mid-Devonian | Representative of Eifelian Eshaness volcanic succession, NW Shetland. |
| Ness of Clousta to the Brigs | Mid-Devonian | Representative of Givetian Clousta volcanic rocks, Walls, Shetland. |
| Point of Ayre | Mid-Devonian | Representative of Givetian Deerness Volcanic Member, mainland Orkney. |
| Too of the Head | Mid-Devonian | Representative of Givetian Hoy Volcanic Formation, Isle of Hoy, Orkney. |
| South Kerrera | Late Silurian to Early Devonian | Representative of Lorn Plateau Volcanic Formation. Exceptional examples of subaerial lava features and interaction of magma with wet sediment. |
| Ben Nevis and Allt a'Mhuilinn | Mid-Silurian 425 Ma | Representative of Ben Nevis Volcanic Formation.
Exceptional intrusive tuffs. Internationally important as example of exhumed root of caldera, and historically for development of cauldron subsidence theory. |
| Stob Dearg and Cam Ghleann | Mid-Lochkovian 421 ± 4Ma | Representative of succession in eastern part of Glencoe caldera, including basal sedimentary rocks. Exceptional rhyolites, ignimbrites and intra-caldera sediments. Possible international importance for radiometric dating in conjunction with palaeontology close to Silurian–Devonian boundary. |
| Crawton Bay* | Late Silurian–Early Devonian | Representative of Crawton Volcanic Formation. |
| Scurdie Ness to Usan Harbour | Early Devonian | Representative of 'Ferrydean' lavas and 'Usan' lavas, comprising lower part of Montrose Volcanic Formation. |
| Black Rock to East Comb | Early Devonian | Representative of 'Ethie' lavas, comprising upper part of Montrose Volcanic Formation. |
| Balmerino to Wormit | Early Devonian (Lochkovian) 410.6 ± 5.6 Ma | Representative of eastern succession of Ochil Volcanic
Formation. Possible international importance for radiometric dating in conjunction with palaeontology close to Silurian–Devonian boundary. |
| Sheriffmuir Road to Menstrie Burn | Early Devonian 416 ± 6.1 Ma | Representative of western succession of Ochil Volcanic Formation. Exceptional topographic expression of Ochil fault-scarp. |
| Tillycoultrie | Early Devonian 415–410 Ma | Representative of diorite stocks, intruded into Ochil Volcanic Formation, surrounded by thermal aureole and cut by radial dyke swarm. Exceptional examples of diffuse contacts due to metasomatism and contamination, with 'ghost' features inherited from country rock. |
| Port Schuchan to Dunure Castle | Early Devonian | Representative of Carrick Hills volcanic succession. Exceptional features resulting from interaction of magma with wet sediment are of international importance. |
| Culzean Harbour | Early Devonian | Representative of inlier of Carrick Hills volcanic succession. Exceptional features resulting from interaction of magma with wet sediment are of international importance. |
| Tumberry Lighthouse to Port Murray | Early Devonian | Representative of most southerly inlier of Carrick Hills volcanic succession. Exceptional features resulting from interaction of magma with wet sediment are of international importance. |
| Pettico Wick to St Abb's Harbour | Early Devonian c. 400+ Ma | Representative of volcanic rocks in the SE of the Southern Uplands. Exceptional vent agglomerates, block lavas, flow tops and interflow high-energy volcaniclastic sediments. |
| *described in this volume |