Figures and tables

Figures

(Figure 1.1) Chronostratigraphy and radiometric dates for the Lower Jurassic Series and its constituent stages. Based on Harland et al. (1990) and Pálfy et al. (2000c).

(Figure 1.2) Outcrop and subcrop map for the Lias Group in England and Wales showing the location of the main sedimentary basins. After Cox et al. (1999).

(Figure 1.3) Sequence of zones, subzones and biohorizons for the Hettangian Stage, with the stratigraphical ranges of ammonite genera indicated (solid line — proven; dashed line — inferred ghost range). After Page (2002) and unpublished observations.

(Figure 1.4) Sequence of zones, subzones and biohorizons for the lower part of the Sinemurian Stage, with the stratigraphical ranges of ammonite genera indicated (solid line — proven; dashed line — inferred ghost range). After Page (2002) and unpublished observations.

(Figure 1.5) Sequence of zones, subzones and biohorizons for the upper part of the Sinemurian Stage, with the stratigraphical ranges of ammonite genera indicated (solid line — proven; dashed line — inferred ghost range). After Page (2002) and unpublished observations.

(Figure 1.6) Sequence of zones, subzones and zonules for the Pliensbachian Stage, with the stratigraphical ranges of ammonite genera indicated (solid line — proven; dashed line — inferred ghost range). After Page (2002) and unpublished observations.

(Figure 1.7) Sequence of zones, subzones, biohorizons and zonules for the lower part of the Toarcian Stage, with the stratigraphical ranges of ammonite genera indicated (solid line — proven; dashed line — inferred ghost range). After Page (2002) and unpublished observations.

(Figure 1.8) Sequence of zones, subzones and zonules for the upper part of the Toarcian Stage, with the stratigraphical ranges of ammonite genera indicated (solid line — proven; dashed line — inferred ghost range). After Page (2002) and unpublished observations.

(Figure 1.9) Generalized palaeogeographical reconstruction for the North Atlantic region during the Early Jurassic Epoch (light shading — sea; dark shading — land). After Scotese (2002).

(Figure 1.10) Palaeogeographical reconstruction for the British area during the Hettangian Stage of the Lower Jurassic Series (light shading — sea; dark shading — land). After Bradshaw et al. (1992).

(Figure 1.11) Lithostratigraphical nomenclature for the Lias Group in Britain showing the dominant lithologies of each formation. Thick lines indicate the formational boundaries. Based on Cox et al. (1999) and Morton (this volume).

(Figure 1.12) Proposed belemnite biozonation schemes for the Lower Jurassic Series of north-west Europe. Based on Doyle (1990–1992), Doyle and Bennett (1995) and Combémorel (1997).

(Figure 1.13) The Gryphaea evolutionary lineage, showing pronounced paedomorphosis and size increase. All specimens are from the Severn Basin. From left to right: Gryphaea arcuata, Bucklandi Subzone, Hock Cliff GCR site; G. mccullochi, Oxynotum Subzone, Bishops Cleeve; G. gigantea, Spinatum Zone, Bredon Hill. G. gigantea is 11.5 cm across.

(Figure 1.14) Range chart for 27 common species of Rhaetian to Pliensbachian bivalve. From data compiled by Peter Hodges. See text for details.

(Figure 1.15) Range chart for Lower Jurassic scaphopods. Data from Richardson (1906a); with taxonomy revised by Engeser and Riedel (1992).

(Figure 1.16) Stratigraphical distribution of rhynchonellid brachiopods in the Lower Jurassic Series of Britain. Data mainly from Ager (1956–1967).

(Figure 1.17) Brachiopod zonation for the Lower Jurassic Series of France. After Ahneras et al. (1997).

(Figure 1.18) Stratigraphical range chart for Lower Jurassic isocrinid crinoids. After Simms (1989).

(Figure 1.19) Microfaunal and microfloral biostratigraphy for the British Lower Jurassic Series. Foraminifera after Copestake (1989); ostracods after Ainsworth et al. (1998a); dinoflagellates after Riding and Thomas (1992); miospores after Koppelhus and Batten (1996); calcareous nannofossils after Bown (1987).

(Figure 2.1) The major structural elements and sub-basins of the Wessex Basin and its margins. Numbers correspond to the locations of the GCR sites: 1— Pinhay Bay to Fault Corner and East Cliff; 2 — Cliff Hill Road Section; 3 — Blue Anchor—Lilstock Coast; 4 — Hurcott Lane Cutting; 5 — Babylon Hill; 6 — Ham Hill; 7 — Maes Down; 8 — Lavernock to St Mary's Well Bay; 9 — Pant y Slade to Witches Point; 10 — Viaduct Quarry; 11 — Hobbs Quarry; 12 — Bowldish Quarry; 13 — Kilmersdon Road Quarry; 14 — Huish Colliery Quarry; 15 — Cloford Quarry; 16 — Holwell Quarry; 17 — Leighton Road Cutting. After Lake and Karner (1987).

(Figure 2.2) Lithostratigraphical subdivisions and stratigraphical ranges of GCR sites for the Lias Group of the Dorset coast, in the southern part of the Wessex Basin.

(Figure 2.3) Lithostratigraphical subdivisions and stratigraphical ranges of GCR sites for the Lias Group in the northern part of the Wessex Basin (Central Somerset and Bristol Channel basins) and the Mendip High and Welsh Massif.

(Figure 2.4) Coastal sections of the Lower Jurassic Series between Pinhay Bay and East Cliff. Based on douse (1989) and Hesselbo and Jenkyns (1995).

(Figure 2.5) Looking eastwards along Church Cliffs to Black Ven. The classic limestone–mudstone alternations of the Blue Lias Formation are exposed in Church Cliffs, with the various members of the Charmouth Mudstone Formation exposed in the extensively slipped cliffs of Black Ven behind. The pale mudstones of the Belemnite Marl Member are clearly visible across the middle of Black Ven. (Photo: M.J. Simms.)

(Figure 2.6) a. Section through the Penarth Group, Blue Lias Formation, Shales-with-Beef Member and basal Black Ven Marl Member west of Charmouth. After Hesselbo and Jenkyns (1995); with ammonite zones, sub-zones and biohorizons after Page (1992); and bed numbers after Lang (1924), Lang et al. (1923) and Lang and Spath (1926). b. Key to lithologies.

(Figure 2.7) Diagenetic concretion in the Shales-with-Beef Member containing a topotype specimen of the ammonite subzonal index fossil Microderoceras birchi (M. J. Simms collection, 1981). (Photo: M.J. Simms.)

(Figure 2.8) Section through the Black Ven Marl, Stonebarrow Pyritic and Belemnite Marl members of the Charmouth Mudstone Formation on Black Ven and Stonebarrow. After Hesselbo and Jenkyns (1995); with ammonite zones, subzones and biohorizons after Page (1992); and bed numbers after Lang and Spath (1926) and Lang et al. (1928).

(Figure 2.9) The pseudoplanktonic crinoid Pentacrinites fossilis, originally described from the Stellare Subzone of the Dorset coast. Specimen collected by M.J. Simms (1982); now in the Natural History Museum, London (BMNH E69605). (Photo: M.J. Simms.)

(Figure 2.10) Conspicuously striped mudstones and marls of the Belemnite Marl Member, overlying dark mudstones of the Stonebarrow Pyritic Member (largely obscured by talus) at the eastern end of Stonebarrow, Charmouth. (Photo: M.J. Simms.)

(Figure 2.11) Section from the (Lower Pliensbachian) Green Ammonite Mudstone Member to the (Toarcian) Down Cliff Clay Member of the Dorset coast. After Hesselbo and Jenkyns (1995); with ammonite zonules after Phelps (1985); and bed numbers after Lang (1936) and Howarth (1957).

(Figure 2.12) The sheer cliff face of the Eype Clay Member below Golden Cap, part of the spectacularly thick development of the Stokesi Subzone in Dorset. Thorncombe Beacon and East Cliff are visible in the distance. (Photo: M.J. Simms.)

(Figure 2.13) The Bridport Sand Formation at East Chit west of Burton Bradstock. (Photo: M.J. Simms.)

(Figure 2.14) Geological map of the Burton Bradstock area showing the location of the Cliff Hill Road Section. After House (1989).

(Figure 2.15) The section through the Lower–Middle Jurassic boundary exposed at the northern end of Cliff Hill Road Section, Burton Bradstock. After Hesselbo and Jenkyns (1995); with bed numbers for the Inferior Oolite Group from Callomon and Cope (1995).

(Figure 2.16) The eastern side of Cliff Hill Road, looking north. The continous hard band just below the vegetation is Bed 37. (Photo: M.J. Simms.)

(Figure 2.17) Generalized geological map of the Blue Anchor–Lilstock Coast GCR site showing specific locations mentioned in the text.

(Figure 2.18) Composite log of the Penarth Group and Lias Group succession exposed on the north Somerset coast. After Warrington and Ivimey-Cook (1995); with ammonite biohorizons in italics based on Page (1992) and Bloos and Page (2000a,b). In the Lias Group only limestones (vertical hatching) and mudstones (blank) are distinguished.

(Figure 2.19) The basal Lias Group and candidate Global Stratotype Section and Point (GSSP) for the base of the Hettangian Stage and Jurassic System at St Audrie's Bay, Somerset. The lowest level at which Psiloceras has been found is in Bed 8, visible immediately above the person's head. (Photo: M.J. Simms.)

(Figure 2.20) Limekiln Steps, East Quantoxhead, west of Kilve, the Global Stratotype Section and Point (GSSP) for the base of the Sinemurian Stage. The limestone platform at the foot of the cliff is the top of Bed 144 and the Hettangian–Sinemurian boundary lies in the thick shale unit at the base of the cliff (beds 145–146). (Photo: M.J. Simms.)

(Figure 2.21) Geological map of the area around the Hurcott Lane Cutting GCR site showing the location of other published sections through the Beacon Limestone Formation.

(Figure 2.22) Landslip exposing the Barrington Limestone Member of the Beacon Limestone Formation on the east side of Hurcott Lane. The conspicuous notch is at about the level of beds 11–13. (Photo: M.J. Simms.)

(Figure 2.23) Section through the Barrington Limestone Member of the Beacon Limestone Formation exposed in I Iurcott Lane Cutting. After B. Constable, 1992, MSc thesis, Birkbeck College, London.

(Figure 2.24) Geological map of the Babylon Hill area.

(Figure 2.25) The Bridport Sand Formation exposed in Bradford Hollow, Babylon Hill, Yeovil. (Photo: M.J. Simms.)

(Figure 2.26) Sections through the Bridport Sand Formation on the south side of the A30 Sherborne Road (centred on [ST 583 161]) at Babylon Hill, Yeovil. After Prudden in Torrens (1969b).

(Figure 2.27) Geological map of the known outcrop area of the Ham Hill Limestone Member of the Bridport Sand Formation. After Wilson et al. (1958).

(Figure 2.28) Generalized lithostratigraphical succession and facies interpretation for the Ham Hill Limestone Member of the Bridport Sand Formation.

(Figure 2.29) The Main Building Stone of the Ham Hill Limestone Member in the working quarry on Ham Hill. (Photo: M.J. Simms.)

(Figure 2.30) Geology and location map of the Maes Down area.

(Figure 2.31) The Marlstone Rock Member of the Beacon Limestone Formation at Maes Down. (Photo: M.J. Simms.)

(Figure 3.1) Geological sketch map of the Lavernock to St Mary's Well Bay area. After Trueman (1920).

(Figure 3.2) Mudstones and limestones of the St Mary's Well Bay Member overlain by the mudstone-dominated Lavernock Shale Member, as viewed from the west side of Lavernock Bay. The conspicuous limestone beds in the foreground lie immediately below the Planorbis Mudstones. (Photo: M.J. Simms.)

(Figure 3.3) Section through the Blue Lias Formation in Lavernock Bay, based on Waters and Lawrence (1987) and Trueman (1920). The sequence through the Lavernock Shale and Porthkerry members has been compiled from Trueman's (1920) description and should be considered only provisional (see comments in main text). Bed numbers are those of Waters and Lawrence (1987), and Trueman (1920) in brackets.

(Figure 3.4) The section at St Mary's Well Bay, showing the conspicuous tabular limestones of the Bull Cliff Member in the upper part of the cliff overlying the silty mudstones of the Langport Member of the Penarth Group, with prominent sandstones in the Cotham Member visible near the base of the cliff. (Photo: M.J. Simms.)

(Figure 3.5) Sketch map of the Pant y Slade to Witches Point GCR site. After Wilson et al. (1990).

(Figure 3.6) Coastal section from Pant y Slade to Witches Point, showing lateral facies changes in the Lias Group. After Trueman (1922b).

(Figure 3.7) Coarsely bedded marginal facies of the Lias Group resting unconformably on Carboniferous Limestone at the western edge of the Slade Trough. The paler bed immediately above the unconformity, and wedging-out rapidly westwards, is the heavily mineralized boulder bed unique to the Slade Trough. The person, for scale, is standing on the unconformity surface immediately west of the boulder bed (Photo: M.J. Simms.)

(Figure 3.8) Lithological log of the lower part of the marginal facies of the Lias Group within and adjacent to the Slade Trough. After Fletcher (1988).

(Figure 3.9) Sketch map of the geology in the area around Viaduct Quarry and Hobbs Quarry.

(Figure 3.10) Marginal facies of the Hettangian and lowermost Sinemurian stages exposed in the main face of Viaduct Quarry, Shepton Mallet. (Photo: M.J. Simms.)

(Figure 3.11) Sketch section through the marginal facies of the Lias Group at Viaduct Quarry. Bed thicknesses in the upper part of the quarry face are only approximate.

(Figure 3.12) Near-horizontal marginal facies of the Lias Group resting unconformably on Carboniferous Limestone dipping steeply southwards (towards the camera) at Hobbs Quarry, Shepton Mallet. The hammer, for scale, is in the lower left of the picture. (Photo: M.J. Simms.)

(Figure 3.13) Sketch map showing the southern limits of the Planorbis to Bucklandi zones in the Radstock district and the distribution of the Armatum Bed, Jamesoni Limestone and Valdani Limestone. The letters B, K and H correspond to the approximate locations of the three GCR sites of Bowidish Quarry; Kilmersdon Road Quarry and Huish Colliery Quarry. After Donovan and Kellaway (1984).

(Figure 3.14) Lithostratigraphy and correlation of the Radstock GCR sites After Donovan and Kellaway (1984).

(Figure 3.15) The section at Bowldish Quarry, Radstock. The thick limestone towards the top is the Bucklandi Bed, overlain by the Spiriferina Bed and Turneri Clay. The lower part of the face is of more thinly bedded limestones and mudstones of the Planorbis Zone. (Photo: M.J. Simms.)

(Figure 3.16) The brachiopod Spiriferina walcotti, from the Spiriferina Bed at Bowldish Quarry, Radstock. The largest specimen is 43 mm across. Specimens from the T.R. Fry Collection, Bristol City Museum. (Photo: M.J. Simms.)

(Figure 3.17) The recently cleared face of Kilmersdon Road Quarry. The main face is in thinly bedded limestones and mudstone of the Planorbis and Liasicus zones, capped by the planed-off surface of the Bucklandi Bed. The thin Sinemurian succession and the thicker bioclastic limestones of the Armatum Bed and Jamesoni Limestone are exposed in the low face above the conspicuous ledge. (Photo: M.J. Simms.)

(Figure 3.18) Phosphatized specimens of Paltechioceras aureolum (left) and Echioceras raricostatum (right) from the Armatum Bed of Kilmersdon Road Quarry. Paltechioceras is 65 mm across. From the T.R. Fry Collection in Bristol City Museum. (Photo: M.J. Simms.)

(Figure 3.19) The limestone-dominated succession at Huish Colliery Quarry. The lower part of the face exposes limestones and thin mudstones of the Planorbis Zone, overlain by more massive bioclastic limestones of the Armatum Bed and Jamesoni Limestone in the upper part of the picture. (Photo: M.J. Simms.)

(Figure 3.20) Sketch map of the geology in the Cloford and Holwell area of the eastern Mendip Hills.

(Figure 3.21) Pull-apart, sediment-filled fissure (Fissure 24 of (Figure 3.22)) at Cloford Quarry. At least three distinct events are discernable in this example; (1) extension to form a 0.5 m-wide joint-guided pull-apart fissure subsequently filled with pale fine-grained sediment; (2) lateral offset of parts of this fissure by movement on a bedding plane (on which the hammer rests); (3) further extension to form a 0.1 m-wide fissure whose sediment fill (slightly darker and coarser than the earlier fill) is continuous across the bedding plane on which the earlier offset occurred. The bedding plane offset and opening of the second fissure probably represent different phases of the same extensional event. (Photo: M.J. Simms.)

(Figure 3.22) Sketch map of the distribution of Mesozoic fissures identified in Cloford Quarry in May 2000 (widths of fissures not to scale).

(Figure 3.23) Hildoceras (left) and Nodicoeloceras (right) from Fissure CXX at Cloford Quarry, indicating a Lower Toarcian Bifrons Zone age for the infill. Specimens from the Charles Copp Collection at Bristol City Museum. Nodicoeloceras is 50 mm across. (Photo: M.J. Simms.)

(Figure 3.24) Sketch of exposure at Leighton Road Cutting, as seen in 1977, and detail of succession. After Jenkyns and Senior (1991).

(Figure 4.1) Generalized geology of the Severn Basin and western edge of the East Midlands Shelf. Only the main basin-bounding faults are indicated. Numbers correspond to the locations of the GCR sites: 18 — Hock Cliff; 19 — Blockley Station Quarry; 20 — Robin's Wood Hill Quarry; 21 — Alderton Hill Quarry; 22 — Wotton Hill; 23 — Coaley Wood; 24 — Haresfield Hill; 25 — Newnham (Wilmcote) Quarry (Chapter 5); MB — Mickleton Borehole; SPB — Stowell Park Borehole.

(Figure 4.2) Lithostratigraphical subdivisions and stratigraphical ranges of GCR sites for the Lias Group of the Severn Basin.

(Figure 4.3) Geology and location map for the Hock Cliff GCR site.

(Figure 4.4) Simplified graphic log of the succession exposed at Hock Cliff, Fretherne.

(Figure 4.5) Alternating mudstones and limestones of the Bucklandi Zone near the top of the Blue Lias Formation at Hock Cliff, looking eastwards. Bed 2 is exposed at river level on the lower right; the three conspicuous limestone bands in the lower half of the main cliff face are beds 16, 18 and 20, with Bed 22 being the fainter band about 2 m higher. (Photo: M.J. Simms.)

(Figure 4.6) Intact test (32 mm across) of the echinoid Miocidaris lobatum, from the lower part of the Bucklandi Subzone at Hock Cliff. Isolated plates and spines of this species are one of the most common elements of the exceptionally rich and diverse echinoderm fauna at this site. (Photo: M.J. Simms.)

(Figure 4.7) Geology and location map for the Blockley Station Quarry GCR site.

(Figure 4.8) The exceptionally thick development of Luridum Subzone clays at Blockley Station Quarry. The floor of the pit is at about the level of the top of the Crinoid-Belemnite Bed (Bed Z); the projecting, and slightly undercut, band above the second terrace is formed by beds 2–4; the remainder of the succession comprises beds 5 and 6. (Photo: C.J. Underwood.)

(Figure 4.9) Sketch section of the succession at Blockley Station Quarry and correlation with that on the Dorset coast. Roman numerals refer to ammonite faunas described by Callomon and discussed in the text. Based on Callomon (in Hemingway et al., 1969) and unpublished observations by C.J. Underwood.

(Figure 4.10) Geology and location map for the Robin's Wood Hill Quarry GCR site.

(Figure 4.11) View of the upper part of Robin's Wood Hill Quarry. The conspicuous pale band near the top of the lower face is Bed 22; beds 28–30 are visible as a pale band about halfway up the face of the upper quarry; with Bed 35 at the top of the section. (Photo: M.J. Simms.)

(Figure 4.12) Simplified graphic log of the Pliensbachian succession exposed at Robin's Wood Hill Quarry. After Chidlaw (1987).

(Figure 4.13) Geology and location map for the Alderton Hill Quarry GCR site.

(Figure 4.14) Large specimen (70 mm across) of the early teleost Leptolepis coryphaenoides, from the Fish Bed of the Dumbleton Member at Dumbleton Pit, just to the east of Alderton Hill Quarry. Specimen from the Simms Collection, in Bristol City Museum. (Photo: M.J. Simms.)

(Figure 4.15) Incomplete wing (30 mm long) of the dragonfly Heterophlebia buckmani, from the Fish Bed of the Dumbleton Member at Alderton Hill Quarry. Specimen from the Simms Collection, in Bristol City Museum. (Photo: M.J. Simms.)

(Figure 4.16) Outcrop/subcrop map of Toarcian strata in the Severn Basin, showing the geographical distribution of sand-dominated (Bridport Sand Formation > Whitby Mudstone Formation) and clay-dominated successions. The location of the three Cotswold Cephalopod Bed Member GCR sites is indicated: W — Wotton Hill; C — Coaley Wood; H — Haresfield Hill. After Green (1992).

(Figure 4.17) Lithostratigraphical and biostratigraphical correlation of named units within the Cotswold Cephalopod Bed Member (Bridport Sand Formation) at the GCR sites of Wotton Hill (from new observations by Chidlaw), Coaley Wood (after Richardson, 1910b) and Haresfield Hill (after Buckman, 1887–1907; and Richardson, 1904). Ammonite zonal stratigraphy revised by K.N. Page.

(Figure 4.18) General geology and location map for the Wotton Hill GCR site and the Nibley Knoll exposure.

(Figure 4.19) Upper part of the Bridport Sand Formation exposed in the lower quarry at Wotton Hill. Typical Bridport Sand Formation forms the lower, pale part of the central buttress and is overlain by the Cotswold Cephalopod Bed Member, with the Struckmanni Bed forming the conspicuous bipartite unit in its lower part. The Middle Jurassic Birdlip Limestone Formation above is clearly visible towards the top of the quarry in the background; its junction with the Cotswold Cephalopod Bed Member below lies at the level of the conspicuous undercut. (Photo: M.J. Simms.)

(Figure 4.20) Geology and location map for the Coaley Wood GCR site.

(Figure 4.21) Geology and location map for the Haresfield Hill GCR site.

(Figure 4.22) The Lower–Middle Jurassic boundary at Haresfield Hill. The prominent overhanging units are part of the Birdlip Limestone Formation, of Middle Jurassic age. The very thin development of the Cotswold Cephalopod Bed Member lies beneath the lower overhang and overlies an irregular erosion surface on the paler coloured sands of the Bridport Sand Formation. (Photo: K. Hitchings.)

(Figure 5.1) Generalized geology of the East Midlands Shelf. Numbers correspond to the locations of the GCR sites: 26 — Conesby Quarry; 27 — Napton Hill Quarry; 28 — Neithrop Fields Cutting; 29 — Tilton Railway Cutting.

(Figure 5.2) Lithostratigraphical subdivisions and stratigraphical ranges of GCR sites for the Lias Group of the East Midlands Shelf

(Figure 5.3) Geology and location map for the Newnham (Wilmcote) Quarry GCR site.

(Figure 5.4) The section at Newnham (Wilmcote) Quarry as seen at the present day (Ambrose, 2001); and in the mid-19th century (Wright, 1860b).

(Figure 5.5) The basal Lias Group exposed at Newnham (Wilmcote) Quarry (Photo: British Geological Survey, No. A10835, reproduced by permission of the British Geological Survey. © NERC. All rights reserved. IPR/51–14C.)

(Figure 5.6) Geology and location map for the Conesby Quarry GCR site and Yorkshire East Quarry.

(Figure 5.7) The succession exposed in Yorkshire East Quarry. This is essentially the same as that still exposed in Conesby Quarry.

(Figure 5.8) Yorkshire East Quarry, Conesby; trial excavation in mid-1995, prior to SSSI notification. The lower face shows around 7 m of bedded Frodingham Ironstone Member above water level, with the top 1 m corresponding to beds 20–23 and yielding late Stellare to Denotatus subzone faunas. Above, and in the rear cliff, around 3.5 m of Charmouth Mudstone Formation can be seen, of Simpsoni Subzone age. The succession is capped by Quaternary 'Cover Sands'. (Photo: K.N. Page.)

(Figure 5.9) Aegasteroceras and other fossils from the Stellare Subzone or Denotatus Subzone of the Frodingham Ironstone Member at Conesby Quarry. Specimen in the collections of the National Museum of Wales. (Photo: M.J. Simms.)

(Figure 5.10) Schematic section across the Cleveland Basin, Market Weighton High and northern end of the East Midlands Shelf showing the relationship of the Liassic ironstones to the underlying structure. After Howard (1985).

(Figure 5.11) Geology and location map for the Napton Hill Quarry GCR site.

(Figure 5.12) The Upper Pliensbachian succession exposed at the Napton Hill Quarry GCR site. The Marlstone Rock Formation lies at the top of the section, with the sandstone of Bed 33 visible a little lower in the face. The large blocks projecting from the lower part of the right-hand face are some of the doggers that occur in Bed 29. (Photo: M.J. Simms.)

(Figure 5.13) Geology and location map for the Neithrop Fields Cutting GCR site.

(Figure 5.14) The section at Neithrop Fields Cutting. After Edmonds et al.(1965).

(Figure 5.15) Geology and location map of the Tilton Railway Cutting GCR site.

(Figure 5.16) The section exposed at Tilton Railway Cutting. After Roy Clements, unpublished, reproduced with permission.

(Figure 6.1) Sketch map and structure of the Cleveland Basin. After Rawson and Wright (1992).

(Figure 6.2) Lithostratigraphical subdivisions and stratigraphical ranges of GCR sites for the Lias Group of the Cleveland Basin.

(Figure 6.3) Sketch map of Redcar Rocks and Coatham Rocks, showing the location of the named scars and significant ammonite faunas.

(Figure 6.4) Redcar foreshore after storms have washed away the beach sand, exposing mudrocks of the Redcar Mudstone Formation, Calcareous Shale Member. This area exposes part of the 'Upper Bucklandi Beds' of Tate and Blake (1876), of Scipionianum Subzone to Sauzeanum Subzone age. (Photo: K.N. Page.)

(Figure 6.5) Extensive foreshore exposures of the Redcar Mudstone Formation in Robin Hood's Bay at low tide, viewed from Ravenscar. The concentric disposition of the 'reefs' demonstrates the domed structure of the outcrop here. (Photo: M.J. Simms.)

(Figure 6.6) Outcrop map of Lower Jurassic strata on the foreshore around Robin Hood's Bay. After Rawson and Wright (1992).

(Figure 6.7) a. The stratigraphy of the Sinemurian and Lower Pliensbachian succession in Robin Hood's Bay. Lithostratigraphy after Hesselbo and Jenkyns (1995). b. The stratigraphy of the Lower Pliensbachian succession in Robin Hood's Bay. Lithostratigraphy after Hesselbo and Jenkyns (1995).

(Figure 6.8) Cliff and foreshore exposures of the Redcar Mudstone Formation in the southern part of Robin Hood's Bay. The level foreshore in the foreground exposes mudstones of Simpsoni Subzone age and the base of the Oxynotum Subzone is immediately above the conspicuous bipartite bed in the middle distance (the 'Double Band' of Tate and Blake, 1876; Bed 43 of Hesselbo and Jenkyns, 1995). The cycles visible in the lower part of the cliff behind are in the upper part of the Siliceous Shale Member, of Raricostatum Zone age. They are overlain by darker and more homogenous mudstones of the Pyritous Shale and Ironstone Shale members, of Jamesoni Zone age, which are exposed in the upper part of the buttress towards the left of the picture. (Photo: K.N. Page.)

(Figure 6.9) Outcrop map of the main lithostratigraphical units exposed on the foreshore between Robin Hood's Bay and Hawsker Bottoms. After Knox et al. (1990).

(Figure 6.10) The stratigraphy of the Pliensbachian and Toarcian succession between Castle Chamber and Hawsker Bottoms. After Hesselbo and Jenkyns (1995).

(Figure 6.11) Lateral variation in the Cleveland Ironstone Formation along NW–SE transects between Eston and Hawsker. Datum for the Kettleness Member is the Sulphur Band; datum for the Penny Nab Member is the base of the Two Foot Seam. Roman numerals indicate the cycles of Howard (1985). After Young et al. (1990a).

(Figure 6.12) a. The Lower Toarcian succession exposed at Blea Wyke. Based on Hesselbo and Jenkyns (1995) and Howarth (1962a). b. The Lower and Upper Toarcian succession exposed at Blea Wyke. Based on Hesselbo and Jenkyns (1995) and Howarth (1962a).

(Figure 6.13) Concretions of the Peak Stones at least 1.5 m in diameter (Bed xi of Howarth, 1962a) in the Bituminous Shales of the Mulgrave Shale Member (Falciferum Subzone), on the shore below Ravenscar Hotel. (Photo: K.N. Page.)

(Figure 6.14) Outcrop map of the main lithostratigraphical units between Staithes and Port Mulgrave. After Rawson and Wright (1992).

(Figure 6.15) a Section through the Staithes Sandstone and Cleveland Ironstone formations between Cowbar Nab, Staithes, and Rosedale Wyke, Port Mulgrave. After Rawson and Wright (1995). Bed numbers are those of Howarth (1955, 1962a, 1973). The Cleveland Ironstone Formation cycles of Howard (1985) are indicated. b Section through the top of the Cleveland Ironstone and the Whitby Mudstone formations between Cowbar Nab, Staithes, and Rosedale Wyke, at Port Mulgrave. After Rawson and Wright (1995). Bed numbers are those of Howarth (1955, 1962a, 1973).

(Figure 6.16) Foreshore and cliff exposures of the Staithes Sandstone Formation, of Stokesi Subzone age, on the west side of Penny Nab, Staithes. Sandstones and sandy mudstones form the steep lower portion of the cliff (mostly in shade) and are overlain by mudstones, siltstones and ironstones of the Cleveland Ironstone Formation, Penny Nab Member (mainly Subnodosus–Margaritatus subzones) in the less steep (and well-lit) upper part of the cliff. (Photo: K.N. Page.)

(Figure 6.17) Silty mudstones and ironstone bands in the Cleveland Ironstone Formation at Penny Nab, south of Staithes. The Two Foot Seam, the six thin ironstones of the Pecten Seam, and the various beds of the Main Seam above can easily be recognized. The higher part of the cliff face is in the Whitby Mudstone Formation. (Photo: M.J. Simms.)

(Figure 6.18) The long-abandoned alum shale workings on Boulby Cliff, with the Middle Jurassic sandstones of the Dogger Formation rising behind them. (Photo: K.N. Page.)

(Figure 6.19) Sketch section of Boulby Cliff. After Hunton (1836). Bed numbers are those of Howarth (1955) for the Staithes section. Hunton's original lithological notes are on the right-hand side of the column; the modern interpretation of the lithostratigraphy is on the left.

(Figure 6.20) The Pliensbachian succession on the lower face of Boulby Cliff viewed from the abandoned alum workings. The ironstone bands of the Cleveland Ironstone Formation are visible in the upper part of the face. Foreshore reefs are formed by the upper beds of the Redcar Mudstone Formation, Ironstone Shale Member. (Photo: K.N. Page.)

(Figure 6.21) Outcrop map of the Whitby Mudstone Formation on the foreshore between Whitby and Saltwick. After Howarth (1962a).

(Figure 6.22) The Whitby Mudstone Formation in the cliffs at its type location. (Photo: K.N. Page.)

(Figure 7.1) Summary stratigraphy and interpretation of the succession at Dunrobin. After Batten et al. (1986).

(Figure 8.1) Map of the Jurassic (including Lias Group) outcrop in western Scotland, showing the locations of the GCR sites, indicated in bold, as follows: AI — Aird na h-lolaire; AL — Allt Leacach; B — Boreraig to Cam Dearg; CC — Cadha Carnach; H — Hallaig; OL — Ob Lusa to Ardnish; PC — Prince Charles' Cave to Holm; RL — Rubha na Leac. After Hesselbo et al. (1998).

(Figure 8.2) Chronostratigraphical (stages) and lithostratigraphical nomenclature of the Lower Jurassic Series in the Hebrides, with genetic stratigraphical sequences (after Morton, 1989) and sequence stratigraphy (based on Hesselbo and Jenkyns, 1998; and Hesselbo et al., 1998).

(Figure 8.3) Geological map of the Ob Lusa to Ardnish area, eastern part of Broadford Bay, Isle of Skye. The GCR site includes the coastal outcrops from Ob Lusa west to the eastern parts of Ob Breakish and the Ardnish Peninsula. After D.J. Taylor, 1981, BSc thesis, Birkbeck College.

(Figure 8.4) Succession through the Breakish Formation at Ob Lusa [NG 6998 2492] to [NG 6972 2512]. After D.J. Taylor and C. Cointet, modified from Morton and Hudson (1995). The bed numbers of Hesselbo et al. (1998) are shown in square brackets.

(Figure 8.5) Succession in the Ardnish Formation in the Ardnish Peninsula. After D.J. Taylor and C. Cointet, modified from Morton and Hudson (1995). Bed numbers have been revised to start the base of the Ardnish Formation as Bed 1 (= Bed 18 of Morton and Hudson, 1995). The bed numbers of Hesselbo et al. (1998) are shown in square brackets.

(Figure 8.6) Map of Hallaig and the Hallaig Shore area, showing the main topographic features, the limits of the Hallaig landslip and the location of the GCR site. Selected dip arrows shown indicate the effects of the rotation associated with the landslip. The probable position of the Portree Shale and Raasay Ironstone formations, which are not exposed, is interpolated.

(Figure 8.7) Detailed succession of the uppermost Pabay Shale Formation and lower Scalpay Sandstone Formation, together with records of ammonites and some other key fossils. Bed numbers are those of Howarth (1956), on whose work this figure is mainly based, with additional information from Hesselbo et al. (1998) and Phelps (1985). Note that Bed 3 is 4 m thicker than shown here. The boundary between the Pabay Shale and Scalpay Sandstone formations is transitional but taken at the base of Bed 4. Beds 14 to 18 are distinctive marker beds allowing correlation with other sections on Raasay, including the GCR sites at Rubha na' Leac 1.5 km to the south, and Cadha Carnach 1 km to the north.

(Figure 8.8) View from Rubha na' Leac of the prominent peak of Dun Caan and the cliffs of Drum an Aonaich and Cadha Carnach. The main cliff is of Bearreraig Sandstone Formation above a slope developed on the Portree Shale and Raasay Ironstone formations, with the Scalpay Sandstone Formation forming the lower part of the cliff down to sea level. (Photo: N. Morton.)

(Figure 8.9) Geological map of the area around Dun Caan, Isle of Raasay, based on the author's mapping and that of Bradshaw and Fenton (1982). The locations of Tait's trench and the Raasay Ironstone/Portree Shale localities to the north are taken from part of the [British] Geological Survey field slip for Sheet Inverness 31NW.

(Figure 8.10) Succession from the Scalpay Sandstone Formation to the Dun Caan Shale Member north-east of Dun Caan, Isle of Raasay, based on Howarth (1956), Lee (1920) and Morton (unpublished). Bed numbers for the Scalpay Sandstone Formation are modified from those of Howarth, in brackets where this was based on other localities on Raasay.

(Figure 8.11) Simplified geology and locality map of the Storr Lochs–Holm–Prince Charles' Cave area north of Portree, Trotternish, Isle of Skye, showing locations of the main sections (especially for the Toarcian Stage).

(Figure 8.12) Succession from the upper Scalpay Sandstone Formation to the Dun Caan Shale Member at Trotternish, north of Portree, Isle of Skye, based mainly on unpublished descriptions by Bruce Farrer (1994), observations by Morton (unpublished), and data from Murray Edmunds (unpublished) and Lee (1920). The composite section is based on three main localities: south of Holm [NG 520 506] (by Nicol Morton); between Holm and Prince Charles' Cave (approx. [NG 518 490]) (by Bruce Farrer) and south of Prince Charles' Cave [NG 515 471] (Bruce Farrer and Nicol Morton).

(Figure 8.13) Geological map of the northern part of Beinn na Leac and Rubha na' Leac area, showing the main topographic features and localities described in text. The boundary of the notified GCR site is also shown.

(Figure 8.14) Scalpay Sandstone Formation exposed in the cliff at Rubha na' Leac, Raasay. (Photo: N. Morton.)

(Figure 8.15) Succession through the Scalpay Sandstone Formation, Portree Shale Formation (not exposed) and Raasay Ironstone Formation in the shore, cliffs and hillside south and south-west of Rubha na' Leac and the north-east corner of Beinn na Leac, partly modified from Howarth (1956). Bed numbers for the Scalpay Sandstone Formation are those of Howarth's composite measured succession, continued upwards, in brackets where this was based on other localities on Raasay.

(Figure 8.16) Simplified geology and topography map of the western part of the Ardmeanach Peninsula, western Mull. The two main localities discussed, Aird na h-lolaire and Allt na Teangaidh, Gribun, are indicated.

(Figure 8.17) Uppermost Triassic and lowermost Jurassic measured succession just south of Aird na h-lolaire, based mainly on Oates (1976) with additional data from Lee and Bailey (1925) and Oates (1976). The bed numbering is added here for reference.

(Figure 8.18) Composite section through the Lias Group exposed at the Boreraig to Cam Dearg GCR site, Loch Eishon. After Hesselbo et al. (1998).

(Figure 8.19) Geological sketch map of Loch Mine and Allt Leacach.

(Figure 8.20) The lower cascade at Allt Leacach, showing typical limestone–mudstone alternations of the Blue Lias Formation. The mudstone-dominated Bed 30 is represented by the conspicuous undercut about halfway up the cascade. (Photo: M.J. Simms.)

(Figure 8.21) Section through the Blue Lias and Pabay Shale formations exposed in Allt Leacach. After Hesselbo et al. (1998).

Tables

(Table 1.1) Brachiopod biozonal scheme for the Lower Jurassic Series of Great Britain. After Ager (1978, 1990).

(Table 1.2) Terebratulid stratigraphical distribution in the Lower Jurassic Series of Great Britain. After Ager (1990).

(Table 2.1) Table of approximate zone/subzone-pair thicknesses for the Hettangian and basal Sinemurian stages at six different locations. (* = figures estimated from total zone thickness.) Data from Cope et al. (1980a), Warrington and lvimey-Cook (1995) and Page (1992, unpublished Geological Society Correlation Guide).

References