Hooken Cliff Fossil Hunting

March 1790 – A new undercliff is formed. A major landslip lowered and displaced chalk and Upper Greensand below South Down Common, producing the dramatic broken cliffs and isolated rock masses associated with Hooken today. It changed which beds could be examined and left a landscape that continues to evolve. The event should be distinguished from much older dissolution hollows in the Chalk.

1826 – Early coastal stratigraphy. Henry De la Beche’s study of the Chalk and underlying sands around Beer and Lyme Regis helped establish the coastal succession. His work belongs to the beginning of systematic comparison along this coast, before modern formation names and fossil zones were available. It does not make every fossil he listed elsewhere on the coast a Hooken record.

1874 – Meyer’s numbered beds and fossil locality keys. C. J. A. Meyer described the Beer Head and adjoining cliff succession using numbered beds, thickness columns and locality-coded fossil records. His account preserved much more than a general list of chalk fossils: it documented sandy basal beds, phosphatic material, Beer Stone and the overlying flinty chalk. Later workers placed the principal measured section below the Hooken coastguard station. His names and bed boundaries now require historical interpretation.

1894–1904 – Detailed sections and competing chalk zones. James Rhodes measured chalk packages around the old Hooken descent in 1894. The Geological Survey’s 1900, 1903 and 1904 volumes published separate Upper Greensand and Chalk logs for Hooken, Little Beach, Beer Head and the fallen Pinnacles. Rowe’s early-twentieth-century zonal work added echinoid evidence, including a notable Hooken Beach collection of Conulus castanea. Differences between their boundaries remain scientifically useful rather than something to hide.

1951 – A crab from the historical Meyer collection is named. Withers described Rathbunopon woodsi from the small carapace B50779 at the Sedgwick Museum, Cambridge. Its original “Beer Head” label specifies Meyer’s Bed 12; the Survey had associated that numbered bed with Hooken. The record therefore belongs to the historical wider Hooken–Beer area, with the exact modern station unresolved. This is the naming date, not a known date of discovery.

1961 – A condensed and laterally changing basal Chalk. W. E. Smith’s studies of the Cenomanian west of Beer and its detrital minerals clarified the strong lateral changes in the sandy basal limestone. The setting came to be understood as a patchwork of thin deposits, hardgrounds and omitted intervals rather than a miniature but complete standard Chalk succession.

1984 – Named local units and microscopic correlation. Jarvis and Woodroof formalised the local limestone and chalk succession, including the Hooken, Little Beach and Pinnacles units and named hardgrounds. Tocher’s contemporary palynological research preserved detailed Beer Stone Adit logs and sample-by-sample dinoflagellate-cyst data. The work showed how microscopic fossils, inoceramids and physical erosion surfaces could be combined, while making clear that some intervals were absent.

1985–1989 – Statutory conservation of the coast. The Sidmouth to Beer Coast SSSI was notified under the Wildlife and Countryside Act in 1985, with its boundary revised in 1989, following earlier notification in 1952. Its geological interest includes the Upper Greensand, condensed Cenomanian deposits, Beer Stone and erosional changes in the Chalk. Conservation protects the evidence as well as individual specimens.

1987 – Rare ammonites enter the published record. The Hooken landslip was reported as the source of a Sharpeiceras schlueteri specimen, although its precise bed was unknown. Four Protacanthoceras tuberculatum devonense specimens were also recorded from the wider conservation site. These locality records are valuable because the most condensed parts of the succession do not provide a simple, abundant, bed-by-bed ammonite sequence.

Late 1980s–1991 – The global boundary event in an incomplete local section. Carbon-isotope and microfossil work connected the Hooken Cenomanian–Turonian succession with the wider oceanographic event at the end of the Cenomanian. Hart’s published comparison with Dover highlighted the condensed local record. The important result was not that Hooken preserves every part of the event, but that its gaps and surviving beds can be tested against fuller successions.

2001 – Hooken documented as a nationally important reference section. The Geological Conservation Review brought together cliff photographs, correlation diagrams, historical research and fossil evidence for Hooken. It distinguished the principal backscar, displaced towers, Little Beach and Beer Head and documented the younger chalk preserved in solution-subsided masses. Those figures remain important because some named horizons occur only in captions or diagrams.

2004–2011 – Modern formations and ancient chalk dissolution. Modern Upper Greensand work separated Foxmould, Whitecliff Chert and Bindon Sandstone members and illustrated the changing sandstone beds at Little Beach. Studies at Beer Head described deeply dissolved chalk and younger Seaford Chalk lowered into the resulting hollows. BGS accounts incorporated modern Chalk formations and placed the Pinnacles interval with Holywell, superseding older schemes that included it in Beer Head Limestone.

2007 – Traces of a sea advancing over Triassic mudstone. Gallois and Goldring described a small exposure at the foot of the Hooken landslip where basal Upper Greensand rests on red Seaton Mudstone. Boring casts, scratch-marked crustacean burrows and later small burrows preserved the activity of Cretaceous animals in a much older substrate. Their figured specimens and cautious discussion separated trace shape from uncertain animal identity. The work required the landowner’s permission to expose the surface.

March 2026 – Subsidence changes the usable walking route. The South West Coast Path reported closure of the low Under Hooken path because of subsidence and directed walkers onto a clifftop diversion. This is an access event affecting how the site can be visited, not evidence that the entire Branscombe beach is closed. It reinforces the need to check the current route notice and on-site signs rather than relying on old field-guide directions.

Reading this section. The modern succession is described from older to younger rocks. It is followed by separately labelled historical logs, retained because they record beds and fossils that cannot now be matched confidently to every modern marker. Little Beach, the main Hooken backscar, the fallen Pinnacles, Branscombe East Cliff and Beer Head are distinguished throughout. No thicknesses from different exposures have been added together.

Mercia Mudstone Group

Branscombe Mudstone Formation · Late Triassic

Seaton Mudstone Member

Separate basal-foot exposure. Gallois and Goldring documented a small outcrop at SY210881, about 300 m east of Branscombe Mouth, beneath the landslip. Red silty Seaton Mudstone is well jointed and largely unweathered below its upper disturbed surface. This is a separate observation window at the foot of the slope, not a continuous measured connection to the chalk cliffs or a 115 m local section inferred from the regional member thickness.

Softened upper Seaton Mudstone. Figure 4 distinguishes about 0.15 m of softened red mudstone immediately beneath the unconformity from the unweathered, well-jointed mudstone below. The upper zone is penetrated by the Cretaceous sand-filled traces described here; it is a weathered and burrowed part of the older substrate, not a separate formal member.

Triassic–Cretaceous unconformity. The erosion surface cuts the red mudstone and has shallow clay-filled depressions, up to about 3 mm deep, spaced roughly 150–200 mm apart. Sand-filled cavities and mostly low-angle burrows extend about 150 mm beneath it. These traces were made during the Cretaceous marine transgression into a Triassic substrate; their position in red mudstone does not make the animals Triassic.

Selborne Group

Upper Greensand Formation · late Albian

Formation and basal setting. Glauconitic marine sands and sandstones underlie the Chalk. In the landslip, slips and fallen rock obscure much of their lower succession. Exposed wet sands can be dark grey but weather yellow-brown; calcareous concretions make resistant ledges. The thick Upper Greensand seen here is not represented by the abbreviated loose boulder succession alone.

Basal Upper Greensand at the landslip foot. The same small research exposure preserved only 60–100 mm of in-situ, dark greenish-grey, fine glauconitic sand above the unconformity. It is intensely bioturbated and contains angular, softened red-mudstone clasts a few centimetres across, locally making up about half the rock, with rare impressions of possible ostreid bivalves. Some clasts are burrowed on all sides, demonstrating disturbance after their incorporation. This thin preserved window is not the total formation thickness.

Flask-shaped boring casts. Type I casts from this locality are identified as Gastrochaenolites ornatus. Specimen TF156 illustrates the rounded, flask-like cavity made by a boring bivalve. No associated body fossil identifies its maker. Modern Pholas dactylus was used only as a comparison and is not a Cretaceous Hooken record.

Varied Type II cavities. Boat-shaped, grooved and dumbbell-like casts record more than one probable producer or later coloniser. Some are tentatively referred to Gastrochaenolites isp.; shell-like impressions were compared with Myopholas and, more plausibly, Girardotia, without establishing either as a securely identified body fossil. Other ornament was compared with Conostichus and possible coelenterate activity. These are explicitly tentative interpretations, not a list of proved local species.

Crustacean scratch-marked burrows. Straight or slightly curved cylindrical casts, about 2 mm and 8–12 mm across, contain muddy sand and red-mudstone fragments. Larger examples bear criss-cross scratches characteristic of Glyphichnus harefieldensis. The authors interpreted them as passive fills of open crustacean burrows in a firm substrate. The relationship between these burrows and the larger cavities was not resolved.

Small secondary burrows. Slender unbranched Planolites isp., about 1 mm across, penetrate the cavity fills and overlying sand. Separate 2–3 mm mud-filled, possibly branching and looping traces were described as arenicolitid-like but not named more precisely. A small Diplocraterion cross-section in a red-mudstone clast on TF158 probably formed after the larger cavity was filled. The figured specimens belong to Locality 3 except TF165 in figure 7d, which comes from the separate eastern Locality 2 and is excluded here.

Foxmould Member

Foxmould thickness reference. The BGS Albian framework reports approximately 26 m in the Beer–Seaton area and explicitly includes Hooken at SY21708795 among its reference localities. This is the source’s approximate local framework estimate, not a sum of the separate historical logs below.

Pinnacles foraminiferal age evidence. Carter and Hart’s foraminifera from Foxmould at the Pinnacles, SY221879, were assigned to benthonic foraminiferal Zone 6, indicating a Late Albian age. The BGS framework reports this precise locality evidence; its adjoining regional ammonite list is not transferred to Hooken.

Sands beneath the fallen Pinnacles. Yellow-grey sands with large grey calcareous “burrs” yielded the historical records Serpula (Vermicularia) concava, Echinospatagus murchisonianus, Exogyra columba, Exogyra conica, Cytherea caperata?, Cardium hillanum, Pleuromya plicata, with casts assigned to Cucullaea, Cyprina, Trigonia. These are the published names, including the question mark, rather than a claim that all nineteenth-century identifications remain valid.

Lower lenticular stone beds. Grey sands below the fossiliferous burrs contain flattened lenses and stone floors crowded with the historical serpulid Serpula (Vermicularia) concava. Lower beds can be obscured by landslip debris; traces of cowstones and clayey green sands were associated with springs in the old coastal description.

Little Beach upper Foxmould: sandstone and yellow sand. The highest package in the Survey’s descending log below the bright-green basal chert-bed deposit is 1½ ft of brown sandstone grading down into yellow sand.

Little Beach upper Foxmould: shelly limestone. A 1–2 ft hard, calcareous, glauconitic rock below the sandstone contains historical Pecten (Neithea) quadricostatus, Exogyra conica, Ostrea vesiculosa.

Little Beach upper Foxmould: bright-green sand. A ½ ft bed of strongly glauconitic green sand lies beneath the shelly limestone.

Little Beach upper Foxmould: concretionary sand. At least 8 ft of yellow-green glauconitic sand with large lenticular, dark-centred calcareous concretions, broken shells and abundant pyrite was exposed below the thin green bed. The base was not established in this short section.

Hooken coastguard-station comparison. The Survey traced the same shelly rock and about 7 ft of underlying grey sand below the Hooken coastguard station. This is a separate observation and not an extra 7 ft to add to the Little Beach section.

Whitecliff Chert Member

Chert-bearing sands and calcarenites. Alternating calcareous sandstone, sandy limestone, nodular or bedded chert, shell-rich pebble beds and erosion surfaces reflect a strongly current-swept shallow sea. Chert becomes less persistent westwards. Its presence alone does not identify the member boundary: near Beer Head chert occurs on different sides of the “Coarse Band” over a short distance. The two 1900 logs below preserve the actual local alternations instead of imposing a guessed modern bed-by-bed correlation.

Historical sandstone sample between chert beds. William Hill’s thin-section description No. 4 is explicitly from Hooken Cliff, Beer Head. The rock consists largely of calcareous shell fragments and a fair number of foraminifera, held in broad areas of calcite cement. Angular to subangular quartz and glauconite are minor; some glauconite occupies foraminiferal tests. Patches of silica were observed but no sponge spicules were seen in that sample. This is a petrographic sample, not a newly measured bed or a claim that all local chert lacks a sponge contribution.

Whitecliff Hardground. The eroded, cemented top of this member is overlain by a pebbly glauconitic bed. That contact, rather than the highest individual chert layer, defines the base of the Bindon Sandstone Member. Gallois’s illustrated Little Beach section shows the nodular hardground immediately beneath Bindon Bed 1.

Bindon Sandstone Member

Bed 1: Coarse Band. The basal pebble-rich, glauconitic sand fills irregularities in the underlying Whitecliff Hardground. At Little Beach it is a thin, clearly separated basal package; it is not an extra formation.

Bed 2: lower calcarenite. Calcareous sandstone and sandy calcarenite overlie the Coarse Band. Gallois’s Little Beach column shows this interval without the chert bands so conspicuous farther east. It remains Bed 2 despite that facies change.

Bed 3: wavy-bedded sandstone. A thicker chert-free sandstone/calcarenite interval has wavy and low-angle cross-bedding picked out by glauconite-rich streaks. The Little Beach column distinguishes it from both Bed 2 below and the differently bedded top package.

Bed 4: upper cross-bedded package. The upper sandstone/calcarenite displays trough cross-bedding and locally disturbed bedding. Its top is truncated by the basal Chalk unconformity. Ammonites used to date this member at Shapwick Quarry are not documented Little Beach or Hooken finds and are not added to the local fossil list.

Basal Chalk unconformity. Erosion, burrowing and mineralisation modified the sea floor before and during deposition of the lowest Chalk. Upper Greensand fragments were incorporated into the basal Beer Head Limestone. The boundary records missing time and should not be portrayed as an uninterrupted change from sandstone into chalk.

Chalk Group

Grey Chalk Subgroup

Beer Head Limestone Formation · Cenomanian

Local thickness and historical divisions. This highly condensed limestone succession thickens into the Hooken area and thins towards Beer Head and Branscombe. The research literature divides the formation into the historical Pounds Pool, Hooken and Little Beach packages. Their former member names are listed as obsolete in the current BGS Lexicon; they are retained below to identify published beds, not presented as current formal subdivisions. Historical A corresponds broadly to the first two, and B to Little Beach. Historical C, the Pinnacles interval, is described with Holywell below. Older totals including C are therefore not directly comparable with modern Beer Head Limestone thicknesses.

Type and reference sections. Hooken Cliffs form the type section of the Beer Head Limestone Formation; the thick arenaceous succession beside the Beer Stone Adit is the key local reference for Meyer’s beds 10–13. The former Hooken Nodular Limestone Member takes its name from this exposure. The historical Pounds Pool Member’s own type section lies north of the GCR boundary, at Pounds Pool Beach, and must not be relabelled Hooken. Little Beach and the Pinnacles give their names to the other historical subdivisions. The Branscombe Hardground also has its stratotype within and immediately beside Hooken.

Historical Pounds Pool Sandy Limestone package · A1. Former member name retained for comparison with the published logs; obsolete as a formal subdivision in the current BGS Lexicon.

Hooken adit basal metre. Tocher independently describes the basal metre at the Beer Stone Adit, SY219879, as yellow-brown coarse calcareous sandstone containing large pieces of the sponge then called Ceriopora ramulosa and fragments of the underlying Small Cove Hardground. Above it, pale-brown, strongly cemented sandy bioclastic limestone leads into the weakly nodular Weston surface. This is an actual adit description, distinct from the more quantitative Beer Head end-member description below.

Basal coarse sandstone. At the foot of Beer Head (SY227879), the eastern limestone-facies comparison section, the basal metre is yellow-brown, very coarse calcareous sandstone, rich in rounded quartz and incorporating pieces of the Upper Greensand hardground. Accessory tourmaline and feldspar underline the continued supply of land-derived sediment.

Upper sandy bioclastic limestone. Paler limestone above contains quartz sand, abundant shell debris and increasingly shelly, weakly nodular beds. Published Hooken fossils include Mantelliceras cantianum, Mantelliceras spp., Mariella cenomanensis, Schloenbachia spp., Cyclothyris schloenbachi, Catopygus columbarius, Holaster spp., with terebratulid brachiopods, oysters, pectinacean bivalves and crustacean remains. Some ammonites have been reworked.

Coralline-sponge material. Acanthochaetetes ramulosus occurs in this basal limestone association. Material formerly called Ceriopora ramulosa or Ceriocava ramulosa was interpreted as a large bryozoan; its recognition as a coralline sponge changed the biological interpretation of the deposit.

Weston Hardground. The top of the member is a burrowed, locally mineralised surface. Its development varies from a distinct hardened contact to weaker glauconitic or iron-stained surfaces. Thalassinoides burrows penetrate the substrate; this is a trace fossil, not a shelled animal.

Historical Hooken Nodular Limestone package · A2. Former member name retained to distinguish the local nodular interval; obsolete as a formal subdivision in the current BGS Lexicon.

Lower and middle nodular limestone. At the Beer Stone Adit section this member reaches about 5 m, compared with about 0.9 m at Beer Head. Grey, sandy, shell-detrital limestone includes rubbly surfaces, scours, intraclasts and composite nodules, commonly around 100–150 mm across. Large shell fragments are locally partly silicified.

Ammonite and bivalve assemblage. Published genera include Hyphoplites, Hypoturrilites, Mantelliceras, Schloenbachia. The member was formerly correlated partly with the saxbii interval, but records of Inoceramus virgatus (historically included under I. striatus) support a largely Mantelliceras dixoni Zone age. The upper part includes Merklinia aspera, the large bivalve called Pecten asper in old accounts.

Lower internal Hooken nodule horizon. The adit log separates an iron-stained or mineralised nodular level within the grey shell-detrital limestone from the enclosing rubbly beds. It is an internal local omission surface, not a newly named regional hardground.

Upper internal Hooken nodule horizon. A higher exposed nodule bed and mineralised surface occur below the composite King’s Hole Hardground. The primary figure distinguishes this horizon from the terminal surface; neither is supplied with an unsupported independent thickness.

King’s Hole Hardground. Several phosphatised surfaces at the top combine into a strongly mineralised, near-planar upper contact. This composite hardground represents interruption and erosion, not an ordinary bedding plane of negligible duration.

Wilmington sandy facies. Around Hooken, parts of the basal limestone succession pass laterally into gritty, shell-rich calcareous sands and calcarenites, locally patchily cemented into nodular “grizzle”. Decalcified sand, comminuted shell and large oyster fragments are characteristic. The Small Cove Hardground is the irregular basal surface recognised in this facies interpretation. Wilmington is shown here as a lateral variation, not a separate layer to stack above A1 and A2; fossils from inland Wilmington are not thereby Hooken records.

Historical Little Beach Bioclastic Limestone package · B. Former member name retained for the complex bioclastic interval; obsolete as a formal subdivision in the current BGS Lexicon.

Basal pebble and hardground interval. The member is about 1.75 m thick at the adit and slightly thicker at Little Beach. A convoluted, cavernous mineralised contact at Beer Head changes laterally into pebbly limestone. Reworked phosphatic material includes Acanthoceras rhotomagense, Calycoceras (Newboldiceras) asiaticum asiaticum, Turrilites costatus, indicating older Middle Cenomanian sediment mixed into the deposit.

Adit Little Beach basal white nodules. At the adit, white nodules about 2–5 cm across are embedded in a light-grey glauconitic, sandy matrix. This basal package is distinguished from the more evenly cemented biomicrite above.

Adit Little Beach calcisphere biomicrite. Moderately hardened, light-grey biomicrite rich in calcispheres overlies the white-nodule bed. Prominent Thalassinoides burrows contain material introduced from the younger Pinnacles package. Calcispheres are microscopic calcareous bodies and are not identified here as the particular species studied at inland Membury.

Main bioclastic limestone. Light grey sandy biomicrite contains abundant shell particles. Holaster subglobosus is common and Conulus castanea less frequent in the indigenous assemblage above the basal pebbles. The honeycomb texture reflects branching Thalassinoides burrows later filled by greener sediment.

Upper Little Beach interval. Rare Acanthoceras jukesbrownei, Calycoceras (Newboldiceras) tunetanum, Calycoceras (Newboldiceras) planecostum support extension into the jukesbrownei Zone. This updates an older, simpler correlation. The basal omission includes parts of the dixoni, inerme and costatus succession; fossil pebbles do not restore the missing sedimentary record.

Humble Point Hardground. The mineralised upper surface caps the member and is penetrated by burrows filled from the overlying glauconitic deposits. Eastward condensation causes it and younger hardground surfaces to approach or merge.

White Chalk Subgroup

Holywell Nodular Chalk Formation · latest Cenomanian to early Turonian

Pinnacles interval · historical Bed C. The GCR and older literature use Pinnacles Member for this local subdivision. It is placed here within the Holywell Nodular Chalk Formation; a separately current formal BGS member rank has not been verified.

Basal quartz- and glauconite-rich interval. At the adit the member is about 2.3 m thick, whereas the GCR account records less than 0.1 m at Little Beach. Its lowest centimetres are especially rich in quartz and glauconite. Older authors measured somewhat different boundary packages at Beer Head, so their values should remain attached to their original logs.

Lower Pinnacles nodule bed. The lower of two pale nodule and phosphatic-intraclast beds occurs above the basal glauconitic sand. Their mixed and repeatedly mineralised contents record condensation and reworking. Regional ammonite lists for Pinnacles-equivalent deposits cannot be assigned wholesale to the main Hooken Pinnacles mass, for which the GCR notes a lack of published ammonite records.

Higher Pinnacles nodule bed. A second pale nodular and phosphatic-intraclast level occurs below the more strongly iron-stained hardground. It is kept separate from that terminal mineralised surface in the adit figure.

Limonitic Nodule Hardground. An iron-stained nodular bed with a phosphatic upper surface divides the lower deposits from the higher sandy interval. Its correlation with particular Plenus Marls omission surfaces has changed with biostratigraphical and isotope work; it should not be labelled as a complete local succession of the eight classic Plenus Marl beds.

Upper sandy limestone. Friable sandy limestone above the limonitic nodules yields the locally documented belemnite Praeactinocamax plenus and brachiopod Orbirhynchia wiesti. These support a Late Cenomanian interpretation. The GCR records four Protacanthoceras tuberculatum devonense specimens from the conservation site, but their occurrence should not be converted into an unqualified bed-specific fauna of every Pinnacles exposure.

Pinnacles pale-yellow indurated bed. Tocher’s adit description distinguishes a pale-yellow, hardened sediment above the two basal white-nodule levels, with a phosphatised top. It belongs to the iron-stained omission-surface complex and must not be counted again as an additional full member.

Upper Pinnacles nodular precursor. Towards the top, the rock becomes paler and more nodular. This is the lower part of the glauconitised, limonite-stained Haven hardground complex, below its terminal surface.

Haven Hardground. The strongly indurated terminal surface is associated with the latest Cenomanian Neocardioceras juddii interval in regional correlation. At Beer Head several surfaces are condensed together. The adit discussion in Tocher includes pebble-preserved Sciponoceras gracile and Neocardioceras juddii and younger Watinoceras in burrow fills and overlying chalk, drawing on the regional ammonite revision. These are retained as the published correlation discussion, not proof of a fresh, precisely located Hooken collection.

Haven surface inoceramid record. Tocher reports the published occurrence of Mytiloides cf. opalensis on the Haven surface at the adit, used in the contemporary scheme to identify the basal Turonian. The tentative identification and the source’s historical zonal interpretation are retained; they are not silently converted into a modern species diagnosis.

Boundary hiatus and environmental record. Microfossil and carbon-isotope studies show that condensed Devon sections omit part of the fuller Cenomanian–Turonian transition seen elsewhere. Earlier correlations assigned more of the basal Pinnacles interval to the guerangeri Zone; subsequent work demonstrated substantial omission. The regional oceanographic event is therefore recorded through an incomplete local rock sequence.

Holywell Nodular Chalk above the Pinnacles Member

Connett’s Hole interval: basal nodular chalk. The old Connett’s Hole Member at the adit is about 9 m thick, excluding the historical Pinnacles Member in that older scheme. Immediately above Haven, the first well-developed nodular hardground horizon forms the base of the nodular package. They belong to the basal White Chalk succession, not to a second Beer Head Limestone package.

Second basal Holywell hardground. A further strong nodular hardground lies above the lowest one in the adit log. Both precede the higher iron-stained nodular beds and the Beer Stone lens.

Lower iron-stained nodule bed below Beer Stone. The lower of two further iron-stained nodular horizons lies above the strongest basal hardgrounds in the adit log. These distinguish the lower package from the more evenly bedded Beer Stone above. They remain unnamed local beds here rather than receiving invented regional marker names.

Upper iron-stained nodule bed below Beer Stone. The second higher iron-stained nodule bed completes the basal nodular package beneath the more evenly bedded calcarenite. Its local position is defined by the sequence, without imposing a regional marker name.

Beer Stone lens. About 3 m of finely granular, weakly cross-laminated calcarenite represents a local concentration of echinoderm debris, especially tiny crinoid plates. A weak nodular hardground caps it. Its lenticular geometry and different development at neighbouring exposures explain why quarry thicknesses and fossils cannot simply be transferred to the coast. The historical adit is a geological reference point, not a place to enter.

Inoceramid-rich chalk and West Ebb Marl. Nodular chalk above the Beer Stone contains abundant inoceramid shell debris and leads up to the West Ebb Marl marker. Mytiloides is important for correlation. The serpulid Filograna avita event identified at West Ebb, north of Beer Head, is thought to be cut out at Hooken and is not listed as a recovered Hooken fossil bed.

First local Mytiloides mytiloides. In the adit zonal account, Mytiloides mytiloides first appears in the nodular chalk between West Ebb Marl and the higher limonitic nodular hardground. This sample-scale record is more precise than a formation-wide fossil list.

First upper limonitic hardground. Above the marl, the lower of two iron-stained hardgrounds lies within a roughly 2.5 m package of nodular and flaser-bedded chalk. Its mineralisation records another pause in accumulation.

Second upper limonitic hardground. The higher iron-stained horizon approaches the lower one westwards as the succession thins. Such converging surfaces are evidence of omission, so their spacing cannot be treated as constant along the cliff.

Branscombe Hardground. This massive, nearly planar hardground caps the surviving Holywell succession at Hooken. Westward towards Mitchell’s Stile Rock it amalgamates with older surfaces; still farther west younger chalk rests almost directly on Upper Greensand. The flinty Holywell package present east of Beer is missing here, so Rowe’s “first flint” does not represent the same age at both places.

Holywell fossil association. The local echinoids include Camerogalerus minimus, Hemiaster nasutulus, Cardiaster truncatus, Cardiotaxis cretacea, Conulus castanea, Hirudocidaris hirudo, Tylocidaris sorigneti. Micraster occurs unusually low. Rowe recorded 30 Conulus castanea from Hooken Beach, including 13 in one block: a historical collection observation, not a present abundance forecast. Mytiloides mytiloides and related early Turonian inoceramids assist correlation; finer historical identifications are retained in the separate source logs below.

New Pit Chalk Formation · Turonian

Basal flinty chalk. Approximately 29 m of New Pit Chalk is recognised in the modern account. Above Branscombe Hardground, relatively smooth white and marly chalk contains abundant flints, including finger-like, branching, semi-tabular and locally columnar forms. The historical Terebratulina-zone total of 105 ft has different boundaries and is not a replacement modern thickness.

Branscombe omission and inoceramid change. Small Inoceramus cf. cuvieri occur immediately above Branscombe Hardground at the adit. The intervening Mytiloides cf. labiatus interval recognised in the thicker White Cliff section is not represented here. That contrast is evidence of omission; it is not a reason to add White Cliff’s fossils or beds into Hooken.

Twin Pyritic Flints. The GCR correlation figure distinguishes this paired flint marker low in the New Pit succession, above the Branscombe surface and below Rowe’s lower marly band. It is a lithological marker, not a separate formation or proof that all black nodules are pyrite.

Rowe’s Two-Foot Band. A lower grey marly interval can be traced through the local succession. Its proposed correlation with New Pit Marl 1 is shown with a question mark in the GCR figure and remains qualified here. At Mitchell’s Stile it approaches the composite hardground as underlying chalk is removed.

Two-Foot Band inoceramid record. Inoceramus cf. cuvieri was also recorded from Rowe’s Two-Foot Band in the adit succession. The “cf.” identification is retained. A higher boundary between the historical I. cuvieri and I. securiformis zones was only suggested near the top of the exposed adit section; it was not demonstrated by a complete published bed-by-bed inoceramid dataset.

Intervening flinty chalk. White chalk with successive large flints separates the lower and upper marly bands in the adit log. The primary section records changes between dispersed flints and more continuous layers; these are preserved individually in the 1903 historical log below rather than assigned unsupported modern bed names.

Rowe’s Four-Foot Band. The higher conspicuous marly interval is tentatively related to New Pit Marl 2. Its historical name is not a reliable thickness measurement everywhere. Published descriptions and the adit figure differ in how they portray the band and an adjacent obscured interval, so no reconciled numerical thickness is asserted here.

Pounds Pool Grey Bed correlation. The GCR diagram traces a higher grey marker through the coastal chalk and suggests a possible New Pit Marl 3 equivalent. This is a correlation name derived from the neighbouring exposure, not a claim that the whole Hooken section has been measured there.

New Pit fauna. Terebratulina lata is an important brachiopod, with Micraster corbovis of the local “lata” type and inoceramids historically identified as Inoceramus cuvieri and I. lamarcki. The agglutinated foraminifer Labyrinthidoma southerhamensis, formerly placed in Haplophragmium or Coskinophragma, is recorded in this part of the local chalk succession. Modern species-level records should not be inferred simply from nineteenth-century zonal names.

Dowlands Marl / Glynde correlation. A conspicuous marly groove marks the transition into the younger nodular chalk. Its regional correlation is with the Glynde marl succession. It is also an important lower limit of deep chalk dissolution near Beer Head.

Lewes Nodular Chalk Formation · late Turonian to early Coniacian

Lower nodular chalk and Southerham Marl. Harder nodular chalk, persistent flints and grey marl seams overlie the New Pit succession. Southerham Marl is among the named marker beds recognised in the conservation section, allowing correlation beyond the changing appearance of the cliff.

Caburn Marl. This higher marl seam is distinguished in the local marker succession. Its value lies in tracing a thin lithological horizon through otherwise similar nodular chalk, rather than in providing a separate collecting layer accessible from the beach.

Bridgewick Flints. This flint marker is identified in the GCR cliff illustration and subdivides the lower to middle Lewes succession.

Bopeep Flints. A separate higher flint marker is identified in the local cliff photographs. It must not be merged with the Bridgewick Flints merely because the two are abbreviated together in a caption.

Annis’ Knob / Breaky Bottom Flint. The local conspicuous flint is correlated with the Breaky Bottom Flint. The Twin Pillars illustration begins below this marker and follows the higher Lewes beds upwards. The name does not imply that every fossil from the separate Annis’ Knob sampling section belongs to Hooken.

Lewes Marl. This marl marker is traced in the Hooken cliff and Twin Pillars interpretations, above the lower formation’s marl and flint horizons.

Lewes Flint. The separately identified Lewes Flint is a siliceous marker, distinct from the neighbouring marl bearing the same geographical name. Both occur in the published local cliff interpretation.

Cuilfail Zoophycos Flint. A distinctive trace-fossil-associated flint provides a higher correlation horizon. Zoophycos describes a sediment-feeding trace structure; it is not an ammonite or a body fossil.

Navigation Marl and associated flints. The Navigation marker lies high in the Lewes succession, above the main Lewes Marl and Flint markers in the illustrated cliff. It helps position the Turonian–Coniacian transition, but the stage boundary should not be guessed from a loose dark flint.

Historical sheet flint. Rowe used a conspicuous sheet-flint level to mark the base of his Micraster cortestudinarium Zone. That historical palaeontological boundary is retained as a correlation observation, not substituted for a modern lithostratigraphical formation boundary.

Hope Gap equivalent. Near the top of the Twin Pillars, a hardground is correlated approximately with the Hope Gap Hardground. The approximation matters because the outcrop is structurally displaced and correlations rely on the complete marker sequence.

Chapel Rock Hardground. This higher hardground marks the top of the Lewes Nodular Chalk in the succession used by the GCR account. Above it the rock becomes the softer, less nodular chalk of the Seaford Formation.

Lewes fossil association. Published local records include Micraster corbovis, Micraster leskei, Micraster normanniae, Sternotaxis plana, thick-shelled Inoceramus lower in the formation and Cremnoceramus in its higher part, with Orbirhynchia and terebratulid brachiopods. Fossil occurrences in fallen masses must be interpreted with their enclosing chalk and marker flints, not height above the present beach.

Seaford Chalk Formation · Coniacian

Lower Seaford Chalk in dissolved and subsided masses. At the high-level Beer Head collapse exposures, at the eastern end of the site, soft white flinty chalk with large fragments of Platyceramus and Volviceramus, survives in the highest parts of the site and in masses lowered into solution hollows near Beer Head. It reaches the Middle Coniacian in the GCR interpretation. This preservation explains why younger chalk can occur beside older beds rather than above them in a simple vertical order.

Seven Sisters Flint Band. The GCR photograph identifies this marker within the high-level, solution-subsided Seaford mass at Beer Head, at the eastern end of the conservation site. Thick sheet flints and larger flint structures elsewhere in that mass reinforce the need to distinguish the younger chalk from ordinary Lewes nodular blocks.

Clay-with-flints and Head. Residual clay, flint-rich material and younger slope deposits fill and overlie dissolution hollows. Gallois described large contrasts between intact chalk and adjacent solution features, including removal down towards the Dowlands Marl. These deposits and the lowered chalk blocks record a long history of weathering before the modern sea cliff formed.

Beer Head summit veneer. Gallois described less than 0.5 m of soil and subsoil at the highest point of the Beer Head summit. This thin cover is separate from the deep dissolution hollows nearby and does not establish a uniform thickness over Hooken.

Beer Head dissolution hollows. Steep-sided hollows reach about 30 m down towards the Dowlands Marl and contain Clay-with-flints and Head. Their depth is a dissolution feature in the eastern comparison section, not an extra sedimentary formation thickness or a measure of the 1790 slip.

Beer Head partially dissolved chalk mass. At the eastern end of the headland a partly decalcified interval up to about 30 m thick contains distinct intact masses of Lewes Nodular Chalk and younger Seaford Chalk. This structural mixture must be distinguished from a normally bedded 30 m Seaford succession. Subsidence measurements from the separate Annis’ Knob locality are not added here.

Basal-foot Head: lowest sandy layer. Above the small in-situ Upper Greensand exposure at Locality 3, figure 4 records 0.3 m of wet greenish-grey sand with chert and sandstone clasts. It is landslip-derived Head, not another Cretaceous bed.

Basal-foot Head: middle sandy layer. A separate 0.2 m pale greenish-yellow sand contains flint, chert and sandstone clasts above the wet lower layer.

Basal-foot Head: upper clayey layer. The upper package in the illustrated small section is 0.3 m of reddish-brown, stony, clayey sand. These three Head layers belong to the slope deposit above the basal-foot exposure and are not combined with the high-level Beer Head dissolution fills.

The 1790 landslip and continuing cliff change. The March 1790 collapse created the spectacular undercliff and displaced rock towers. Weak, water-affected beds in the lower succession contributed to failure, but published descriptions differ in how precisely they place the slip surface. Ancient karst subsidence, the 1790 landslip and present rockfall are separate processes, all relevant to the complicated outcrop. None makes the blocks stable or the old access paths safe.

Historical records: how to use them. The following logs preserve original units and names as a record of what was observed. They are not additional strata to add to the modern succession. Feet and inches remain unconverted where conversion would imply unwarranted precision. Fossil names are historical unless a modern equivalent is explicitly given. “BH” in Meyer’s table means Beer Head in his broader local sense; subsequent Survey discussion locates the principal measured section below the Hooken coastguard station, but not every BH specimen can be placed at the adit.

De la Beche 1826: western coastal section. The text locates the coastal Beer Stone exposure in the Branscombe cliffs west of Beer Head, describing a shaft and level opening in the cliff. Plate XVI figure 4 illustrates its historical sequence. The following labelled packages are kept in descending order without forcing their boundaries into modern formations. The separate eight-bed workmen’s log on page 117 belongs to the inland Beer quarries and is excluded.

De la Beche figure 4: Flintless chalk. The diagram begins with chalk without flints above the worked stone. No separate thickness is given in this schematic column.

De la Beche figure 4: Beer Stone. A separately bracketed, horizontally divided worked-stone interval lies beneath the flintless chalk. The diagram identifies its position, rather than supplying a modern member boundary.

De la Beche figure 4: Bed not quarried. A distinct unworked bed is labelled immediately beneath the worked Beer Stone. The inland quarry thickness must not be silently assigned to this coastal graphic.

De la Beche figure 4: Light-coloured compact sandstone. A separate light-coloured, hard sandstone lies below the unworked interval.

De la Beche figure 4: Quartz-grained sandstone. The next thicker package is specifically labelled as sandstone containing quartz grains.

De la Beche figure 4: Compact bed d′. A thin resistant layer separates the quartz-grained sandstone from the lower green-earth sandstone. Its historical letter is retained without a guessed modern bed correlation.

De la Beche figure 4: Upper green-earth sandstone. Sandstone containing the material then called green earth occurs beneath d′; the graphic and accompanying text distinguish a further compact level within this lower interval.

De la Beche figure 4: Lower compact level. The thin hard bed drawn within the green-earth sandstone is distinct from d′ above.

De la Beche figure 4: Ferruginous green-earth sandstone. The lower part of the green-earth sandstone package carries the ferruginous-parts annotation, recording iron-rich material as well as the green grains.

De la Beche figure 4: Chert-seamed sandstone. The lowest illustrated package contains repeated chert seams in sandstone. The scheme predates the modern Upper Greensand member nomenclature.

Meyer 1874, bed 2. No separate BH thickness is established here; the lower sandy succession has a BH record of Trigonia spectabilis.

Meyer 1874, bed 4. Pale or yellowish marly sands and concretions, 20 ft in the BH thickness column. The broader bed fauna was not locality-keyed sufficiently to transfer every listed species to Hooken.

Meyer 1874, bed 5. Chert-bearing sand. Meyer’s headline BH thickness is 20 ft, while the accompanying three-part description gives 6 ft of sand with chert layers, 1 ft of broken-shell rock and 11 ft of lower cherty sand. The 18 ft subtotal is retained as a source discrepancy rather than “corrected” to 20 ft.

Meyer bed 5: upper cherty sand, 6 ft. Sand with chert layers forms the upper subpackage in the accompanying descending description.

Meyer bed 5: broken-shell rock, 1 ft. A distinct hard shell-debris interval separates the upper and lower cherty sands.

Meyer bed 5: lower cherty sand, 11 ft. Lower sand with chert layers completes the three-part description. These values total 18 ft, whereas the headline BH column says 20 ft; the discrepancy remains unresolved.

Meyer 1874, bed 6. Pale sand passing into sandstone, 2 ft 6 in in the BH column. The characteristic oyster was reported under the historical name Exogyra digitata.

Meyer 1874, bed 7. A 2 ft sandstone-pebble bed with large oyster material in the BH column.

Meyer 1874, bed 8. About 10 ft of buff, irregularly bedded sand with pebble-rich levels; the BH-keyed fauna includes Orbitolina concava, Exogyra digitata.

Meyer 1874, bed 9. About 20 ft of buff, sugary-textured glauconitic sandstone and quartz grit in the BH column. A general bed fossil list is not treated as an exact BH occurrence list.

Meyer 1874, bed 10. About 15 ft of yellow quartz sand in a chalky matrix. BH-keyed records are Bryozoa, Siphonia sp., Ananchytes subglobosus, Cottaldia benettiae, Discoidea subuculus, Pyrina ovulum, Pyrina prattii, Salenia petalifera, Gastrochaena sp., Inoceramus latus, Ostrea allied to O. normaniana, Rhynchonella dimidiata, Rhynchonella schloenbachi, Terebratella pectita.

Meyer 1874, bed 11. About 3 ft of yellow quartz- and glauconite-bearing chalky limestone. BH-keyed records are Callianassa?, Bryozoa, Ananchytes laevis, Discoidea subuculus, Micraster sp., Pseudodiadema michelini, Pseudodiadema variolare, Janira quinquecostata, Janira sp., Pecten puzosianus, Pecten asper, Rhynchonella grasiana, Rhynchonella schloenbachi.

Meyer 1874, bed 12. About 2 ft of nodular, rubbly quartz- and glauconite-bearing limestone, with an irregular iron-stained upper surface. BH-keyed records are Bryozoa, Scyphia spp., Spongia spp., Ananchytes subglobosus, Catopygus carinatus, Discoidea subuculus, Pyrina prattii, Pyrina ovulum, Salenia gibba, Salenia petalifera, Spatangus bufo, Pteroceras sp., Anomia sp., Pecten asper, Megerlia lima, Trigonosemus incertus, Terebratula ovata, Terebratula rugulosa, Rhynchonella dimidiata, Rhynchonella convexa, Rhynchonella grasiana, Rhynchonella mantelliana, Rhynchonella wiesti.

Meyer 1874, bed 13. About 5 ft of grey or brown chalky limestone with quartz, glauconite and phosphate. The source explicitly recognises reworked casts. BH-keyed records are Astrea?, Bryozoa, phosphatic sponge nodules, Discoidea subuculus, Echinocyphus difficilis, Pseudodiadema variolare, Belemnitella indeterminate, Ammonites rhotomagensis, Ammonites sp., Turrilites tuberculatus, Arca mailleana, Lucina turoniensis, Rhynchonella mantelliana, Terebratula ovata.

Meyer 1874, bed 14. About 5 ft of nodular chalk with fine quartz in Meyer’s BH column. BH-keyed records are Discoidea subuculus, Cardiaster allied to C. rostratus, Ammonites mantelli.

Meyer 1874, bed 15. About 6 ft of cream or yellowish sandy chalk in the BH column, the local Beer Stone interval. The separately quoted Beer Quarry thickness is not added here. BH-keyed records are Ananchytes subglobosus, Discoidea subuculus, Echinoconus (Galerites) castaneus, Inoceramus mytiloides.

Meyer 1874, bed 16. About 14 ft of flintless, nodular, sandy or partly crystalline chalk in the BH column. BH-keyed records are Ananchytes subglobosus, Cidaris sp., Discoidea subuculus, Echinocyphus difficilis, Echinoconus castaneus, Salenia umbrella.

Meyer 1874, bed 17. Marly or nodular chalk with grey and yellow streaks, finger flints and a basal concentration of larger flints. Meyer’s approximately 10 ft is a general coastal description rather than a securely separate BH measurement. BH-keyed records are Ananchytes subglobosus, Discoidea subuculus, Pseudodiadema michelini, Salenia petalifera, Terebratula semiglobosa var. subundata.

Meyer 1874, bed 18. Nodular chalk with numerous flint layers; the approximately 40 ft figure is from the general description and is not added as an independently measured Hooken thickness. BH-keyed records are Holaster planus, Inoceramus brongniarti, Ostrea vesicularis, Rhynchonella cuvieri.

Meyer 1874, bed 19. Hard flintless chalk with a grey marly band above the middle. The approximately 15 ft total and 3 ft marly band belong to Meyer’s general bed description. BH-keyed records are Discoidea allied to D. minima, Terebratulina gracilis, Terebratulina martiniana, Terebratulina striata, Rhynchonella plicatilis.

Meyer 1874, bed 20. Flinty chalk, about 60 ft in the BH column. Its BH-keyed records are Micraster coranguinum, Terebratulina gracilis. The historical echinoid identification does not establish a modern coranguinum-zone age for every part of this local package.

Meyer’s missing and nonlocal entries. Beds 1 and 3 are not inserted as separately recovered Hooken packages from this source. Fossils keyed only to White Cliff, Dunscombe, Axmouth or another locality are excluded. Examples include the White Cliff/Dunscombe Ammonites varians in bed 12 and the Axmouth Micraster corbovis in bed 16. A broad historical “Beer Head” label should never be silently upgraded to an exact Hooken bed collection.

Survey 1900: western undercliff near Branscombe Mouth. A separate descending section, introduced on page 199 and continued on page 202 after figure 64, totals 60 ft exposed. It belongs to the western Hooken undercliff. The later Kempstone and Dunscombe sections are different localities and are not appended to it.

Western undercliff U01: 6 ft. Hard, speckled greenish-white glauconitic calcareous sandstone.

Western undercliff U02: 15 ft. Soft buff sands with rounded grey calcareous burrs.

Western undercliff U03: 18 ft. Soft bluish-grey glauconitic sands with some burrs and the historical oyster Exogyra conica.

Western undercliff U04: 21 ft seen. Soft grey glauconitic sands with nearly continuous calcareous layers; the exposed base does not establish the full thickness.

Survey 1900: Hooken below the coastguard station. The following sixteen packages are in the source’s descending order. H01 is the highest. The printed 76½ ft total applies to H01–H15 using the upper value of H11; the approximately 3 ft basal shelly rock H16 is printed separately. It must not be folded into that total without saying so.

Hooken H01: 12 ft. Hard calcareous sandstone with wavy bedding low in the bed and scattered brown chert in its lowest 2 ft.

Hooken H02: 1 ft. Coarse yellow-green sand forming a recess.

Hooken H03: 6 ft. Finer buff sand with irregular greenish-grey streaks.

Hooken H04: 5 ft. Buff to yellow-green sand with lenticular calcareous stones and pebbles; broken oyster material is especially conspicuous below.

Hooken H05: 8½ ft. Pebble- and shell-rich sand grading down into rough yellow-green sand with scattered pebbles and historical Exogyra digitata.

Hooken H06: 2 ft. Sand crowded with pebbles and broken shells.

Hooken H07: 8 ft. Sand with fewer pebbles and shells.

Hooken H08: 6½ ft. Grey sand containing dark grey chert and calcareous concretions.

Hooken H09: 3 ft. Whitish-grey calcareous rock passing down into light grey glauconitic sand with calcareous lumps and a few cherts.

Hooken H10: 9 ft. Light grey, knotty calcareous sandstone with regular dark grey to black chert layers.

Hooken H11: 9 in–1 ft. Light grey sand with hard, irregular calcareous concretions.

Hooken H12: 3 ft. Grey sand with lumpy, rounded chert.

Hooken H13: 1 ft. Light grey sand forming a recess.

Hooken H14: 8 ft. Grey sand with hard grey calcareous lumps, some dark-centred; the lower part is particularly concretionary.

Hooken H15: 2½ ft. Soft grey glauconitic sand with shells.

Hooken H16: about 3 ft. Hard, speckled glauconitic limestone with historical Exogyra columba and Pecten (Neithea) quadricostatus.

Hooken lower grey sand beneath H16. The following description records a further 7 ft of grey sand with purplish streaks beneath the hard glauconitic shelly bed. This separately described lower-zone exposure is not silently included in the printed H01–H15 total or in the Little Beach log.

Survey 1900: Little Beach comparison. This is a separate descending 64½ ft section, not a continuation of the Hooken log. L01 is its highest package. The contrasting thicknesses and chert distribution demonstrate rapid lateral change; the logs do not justify matching every row one-to-one.

Little Beach L01: 10 ft. Yellowish bedded glauconitic sandstone, with wavy green-sand seams in its lower part.

Little Beach L02: 1 ft. Coarse yellow-green sand.

Little Beach L03: 3 ft. Hard, rough, lumpy calcareous grit.

Little Beach L04: 6 ft. Compact yellowish sandstone with green-sand seams.

Little Beach L05: 8 ft. Massive greenish sandstone with a layer of pebbles and broken shells.

Little Beach L06: 2 ft. Water-worn sandstone pebbles.

Little Beach L07: 5½ ft. Yellow calcareous sandstone with irregular greenish-grey seams.

Little Beach L08: 6 ft. Sandstone with grey to rusty chert layers.

Little Beach L09: 4 ft. Hard grey calcareous stone and shelly grit with oyster material recorded as Exogyra.

Little Beach L10: 13 ft. Buff sand with black cherts and calcareous concretions.

Little Beach L11: 1 ft. Dark grey, clayey sand.

Little Beach L12: 5 ft. Green glauconitic sand with hollow calcareous concretions and a rough basal pebble bed; the associated account records Radiopora ornata.

Survey 1903: section 50 yards west of Beer Head. The following four packages preserve the descending order of the section on page 134. They belong to this particular historical exposure and are not substituted for the later comparative table, added to the Little Beach observations or converted into modern member thicknesses.

West Beer Head: basal Turonian, 2 ft 9 in. The highest package is hard yellowish, gritty limestone containing glauconite. The Survey assigned it to the base of the Turonian in its historical scheme.

West Beer Head: limestone B, 2 ft 6 in. Hard limestone contains quartz and glauconite, with green-coated nodules at the top and at two levels near the base. Weathering produces a pitted or honeycombed face. The recorded fossils include historical Holaster subglobosus.

West Beer Head: limestone A, 11 ft to 12 ft 9 in. Whitish gritty limestone has green-coated nodules at its top. Its compact, shelly upper part contains historical Pecten asper, Holaster altus, Ammonites (Acanth.) mantelli. The lower part is coarser and contains Ceriocava ramulosa and other organisms then classified as bryozoans.

West Beer Head: underlying Selbornian sandstone, 10 ft. Finer-grained calcareous sandstone lies beneath the coarse limestone, with a well-defined upper surface and few fossils. “Selbornian” is the Survey’s historical term, retained here to distinguish this underlying sandstone from the overlying Chalk packages.

West Beer Head: coarse basal 3–4 ft of A. The lowest part of A is very coarse grit with large quartz grains and pebbles of vein quartz and hornstone. Branching historical Ceriocava ramulosa is conspicuous, with many specimens bored by Lithodomus. Single valves of large Terebratula pectita and Rhynchonella dimidiata were also recorded. This is a subdivision within A, not extra thickness beneath it.

West Beer Head: historical fossil distribution between A and B. The page 135 account reports Holaster subglobosus and Terebratula arcuata as common in B and absent from A; Pecten asper as common in A and apparently absent from B; and Holaster altus and Holaster laevis as common in A but rare in B. These are local historical observations, not universal ranges. Page 136 separately records H. subglobosus in the upper 3 ft of A in the Hooken discussion, so the differing source statements are retained rather than reconciled into an invented uniform distribution.

Western fallen blocks: approximately 2 ft of upper limestone. The more westerly blocks show about 2 ft of greenish limestone, with green sand between the nodular masses and a prominent layer of green-coated nodules at the top. This separate fallen-block observation illustrates lateral facies change, not another bed to add to the measured section.

Little Beach: limestone A, approximately 5 ft. Above the pebble beach, the lower, coarser part of A thins out, leaving the package about 5 ft thick. The source follows this reduced thickness towards the grassy Hooken undercliff slope, where exposure was poor. This is a lateral historical observation, not a present access description.

Little Beach: limestone B, approximately 2 ft. The overlying B package remains about 2 ft thick in the same Little Beach description. Its thickness is independent of the later shore, Pinnacles and Hooken Cliff columns below.

Survey 1903 comparative table: common description of A. For the three locality columns below, A is hard calcareous grit with a phosphatised nodular top planed to a flat surface. The whitish, gritty, shelly limestone contains little glauconite and becomes coarse and rough near its base, with historical Ceriocava ramulosa. Pecten asper and Holaster laevis are common in its upper part. The common lithological description does not make the separately measured columns one section.

Survey 1903 comparative table: common description of B. Hard gritty limestone has a thick layer of brownish, green-coated nodules at the top. Below, it becomes rough, nodular, whitish gritty limestone with green sand in the spaces between nodules and historical Holaster subglobosus.

Survey 1903 comparative table: common description of C. Rough, gritty green glauconitic sand lies in a chalky matrix and contains scattered brown phosphates. The table records historical Actinocamax plenus. This is the source’s older upper-package scheme, not a new formal member.

Survey 1903, shore west of Beer Head: A. The comparative table records more than 12 ft. A is the historical lower sandy and shelly limestone package, B the overlying limestone, and C the glauconitic-phosphatic upper package where preserved. These are source-specific historical divisions; C now belongs with Holywell, and a “more than” value means that the base was not seen.

Survey 1903, shore west of Beer Head: B. The comparative table records 4½ ft. A is the historical lower sandy and shelly limestone package, B the overlying limestone, and C the glauconitic-phosphatic upper package where preserved. These are source-specific historical divisions; C now belongs with Holywell, and a “more than” value means that the base was not seen.

Survey 1903, shore west of Beer Head: C. The comparative table records not separately represented. A is the historical lower sandy and shelly limestone package, B the overlying limestone, and C the glauconitic-phosphatic upper package where preserved. These are source-specific historical divisions; C now belongs with Holywell, and a “more than” value means that the base was not seen.

Survey 1903, fallen Pinnacles: A. The comparative table records more than 16 ft. A is the historical lower sandy and shelly limestone package, B the overlying limestone, and C the glauconitic-phosphatic upper package where preserved. These are source-specific historical divisions; C now belongs with Holywell, and a “more than” value means that the base was not seen.

Survey 1903, fallen Pinnacles: B. The comparative table records 5 ft. A is the historical lower sandy and shelly limestone package, B the overlying limestone, and C the glauconitic-phosphatic upper package where preserved. These are source-specific historical divisions; C now belongs with Holywell, and a “more than” value means that the base was not seen.

Survey 1903, fallen Pinnacles: C. The comparative table records 4 ft. A is the historical lower sandy and shelly limestone package, B the overlying limestone, and C the glauconitic-phosphatic upper package where preserved. These are source-specific historical divisions; C now belongs with Holywell, and a “more than” value means that the base was not seen.

Survey 1903, Hooken Cliff: A. The comparative table records 18 ft. A is the historical lower sandy and shelly limestone package, B the overlying limestone, and C the glauconitic-phosphatic upper package where preserved. These are source-specific historical divisions; C now belongs with Holywell, and a “more than” value means that the base was not seen.

Survey 1903, Hooken Cliff: B. The comparative table records 5½ ft. A is the historical lower sandy and shelly limestone package, B the overlying limestone, and C the glauconitic-phosphatic upper package where preserved. These are source-specific historical divisions; C now belongs with Holywell, and a “more than” value means that the base was not seen.

Survey 1903, Hooken Cliff: C. The comparative table records 6 ft. A is the historical lower sandy and shelly limestone package, B the overlying limestone, and C the glauconitic-phosphatic upper package where preserved. These are source-specific historical divisions; C now belongs with Holywell, and a “more than” value means that the base was not seen.

Survey 1903: interpretation of A–C. Meyer’s bed 10 was compared with A, beds 11–12 with B, and bed 13 with C. The Survey records phosphatic Ammonites hippocastanum as derived material, Rhynchonella wiesti and forms compared with R. mantelliana, Actinocamax plenus, and Galerites subrotundus near the upper contact. These are historical identifications and correlations, not a modern taxonomic revision or proof of an unbroken succession.

Historical crab type from Meyer’s wider Beer Head locality. Rathbunopon woodsi was named by Withers in 1951 from a small crab carapace in the Meyer collection at the Sedgwick Museum, Cambridge, specimen B50779. The original published provenance is Cenomanian, upper varians Zone, Meyer’s Bed 12, “Beer Head”. The Survey’s 1903 discussion places Meyer’s Bed 12 at Hooken, within its upper part of B. This supports a historical broader Hooken–Beer-area association, but does not resolve a precise modern collecting station or bed correlation. It is not assigned to the measured adit log. A 2011 revision refigured the holotype. It is a significant collection record, not a claim of a common beach find or an exact modern Beer Head foreshore occurrence.

Survey 1903: Beer Head lower White Chalk. The following five packages are descending below soft white flinty chalk. Together they total 15 ft 3 in in the published section. Beer Stone was not recognised here, unlike Hooken.

Beer Head lower White Chalk W01: 1 ft 6 in. Soft, flintless chalk.

Beer Head lower White Chalk W02: 6 in. Hard yellow limestone, firmly attached to the bed below.

Beer Head lower White Chalk W03: 6 ft 6 in. Rough nodular, shelly chalk with historical Cardiaster pygmaeus, Discoidea dixoni and cidarid spines.

Beer Head lower White Chalk W04: 5 ft. Hard nodular chalk containing sparse glauconite.

Beer Head lower White Chalk W05: 1 ft 9 in. Hard yellow limestone with quartz and glauconite, sharply bounded above.

Pinnacles lower White Chalk: lower package. 1 ft 9 in. Basal hard limestone comparable with the lowest Beer Head bed. The source’s rounded total of about 20 ft does not exactly equal the separately quoted components and has not been silently recalculated.

Pinnacles lower White Chalk: middle package. 7 ft. Gritty yellow-grey chalk. The source’s rounded total of about 20 ft does not exactly equal the separately quoted components and has not been silently recalculated.

Pinnacles lower White Chalk: upper package. about 12 ft. Rough nodular chalk, with a roughly 9 in limestone at its top. The source’s rounded total of about 20 ft does not exactly equal the separately quoted components and has not been silently recalculated.

Hooken lower White Chalk, historical bed 14: 7 ft. Hard nodular chalk grading into gritty chalk, with historical Galerites subrotundus near the base. These are the Survey’s later measurements, not replacements for Meyer’s differently quoted values.

Hooken lower White Chalk, historical bed 15: 6 ft. Compact, evenly streaked Beer Stone. These are the Survey’s later measurements, not replacements for Meyer’s differently quoted values.

Hooken lower White Chalk, historical bed 16: 13 ft. Rough nodular chalk, including a roughly 12 in streaky interval in its middle. These are the Survey’s later measurements, not replacements for Meyer’s differently quoted values.

Hooken lower White Chalk, historical bed 17: 6 ft. Compact streaky chalk with a few flints and a basal flint line. These are the Survey’s later measurements, not replacements for Meyer’s differently quoted values.

Historical lower-White-Chalk boundary. The Survey’s 26 ft total for Hooken corresponds to beds 14–16, although its correlation discussion also includes the overlying flinty bed 17. Modern interpretation places the local first flinty chalk above the Branscombe omission surface in New Pit. The older boundary choices must therefore remain visible rather than forcing all four beds into Holywell.

Survey 1903: Hooken landslip Terebratulina-zone log. Ten descending packages total 105 ft. The section was measured partly by Jukes-Browne and partly by Rhodes between the historical paths from Little Beach and the clifftop. It records past exposures, not an instruction to follow those paths today. Rough yellow phosphatic nodular chalk above was assigned to the base of the old Holaster planus Zone and was not counted in the 105 ft.

Hooken T01: 13 ft. Less nodular chalk with layered and scattered flints, grey marly streaks low in the bed and Micraster corbovis.

Hooken T02: ½ ft. Thin grey shaly marl.

Hooken T03: 26 ft. Massive chalk with flint layers 2–4 ft apart and scattered flints; historical Terebratulina gracilis var. lata.

Hooken T04: 6 ft. Massive grey-white chalk with few flints and T. gracilis var. lata.

Hooken T05: 2 ft. Grey marly chalk with T. gracilis var. lata.

Hooken T06: 3 ft. Massive flintless chalk with T. gracilis var. lata.

Hooken T07: 11 ft. Grey-streaked marly chalk with several layers of large flints and T. gracilis var. lata.

Hooken T08: 21 ft. Chalk with numerous scattered flints.

Hooken T09: 2½ ft. Greyish chalk with marl at its base.

Hooken T10: 20 ft. Chalk with layered and scattered flints and Terebratulina lata.

Survey 1903 fossil table: locality key c. The following lists retain only the cells keyed “c”, meaning Beer Head and Hooken. They cannot separate those two localities more finely. Rowe’s adjoining “x” columns pool Devon-coast records and are not treated as Hooken occurrences. Question marks, “cf.” and “allied to” qualifications are preserved; spellings and generic assignments remain historical.

Historical fauna, bed 14. Rhynchonella cuvieri, Rhynchonella cf. dimidiata, Terebratula cf. arcuata, Cardiaster pygmaeus, Cardiaster allied to C. rostratus, Cidaris hirudo, Discoidea dixoni, Discoidea minima, Galerites castanea, Galerites subrotundus.

Historical fauna, bed 15. Inoceramus mytiloides, Lima sp., Cardiaster pygmaeus, Discoidea dixoni, Discoidea minima, Galerites castanea.

Historical fauna, bed 16. Inoceramus brongniarti?, Inoceramus cf. cripsi, Inoceramus mytiloides, Ostrea vesicularis, Teredo amphisbaena, Rhynchonella cuvieri, Terebratula semiglobosa, Cardiaster pygmaeus, Cidaris cf. perornata, Discoidea dixoni, Echinocyphus difficilis?, Galerites castanea, Galerites subrotundus, Hemiaster minimus, Peltastes clathratus?.

Historical fauna, bed 17–19. Lamna appendiculata, Scapanorhynchus raphiodon, Ostrea vesicularis, Radiolites cf. angeoides, Spondylus spinosus, Rhynchonella cuvieri, Rhynchonella plicatilis, Terebratula semiglobosa, Terebratulina gracilis var. lata, Terebratulina striata, Cidaris sorigneti, Discoidea dixoni, Galerites subrotundus, Hemiaster minimus, Holaster planus, Micraster corbovis, Pseudodiadema sp., Salenia granulosa, Parasmilia centralis.

Survey 1904: Rhodes’s 1894 Hooken bluff section. This separate log was measured in bluffs beside and above the old descent east of the coastguard station. Four descending packages were described. Rowe later had difficulty recognising the same old planus boundary there, illustrating both changing exposure and changing zonal interpretation. These units are not an additional thickness to append to the 105 ft log.

Rhodes R01: 8 ft. Rough chalk with scattered flints and an inaccessible basal flint layer.

Rhodes R02: 24 ft. Rough chalk with scattered flints and a well-marked basal flint layer.

Rhodes R03: 16 ft. Rough chalk with hard lumps and a few flints; historical Holaster planus was recorded near both top and base.

Rhodes R04: 2 ft. Rough yellow phosphatic nodular chalk with historical Micraster corbovis, Holaster planus, Cyphosoma radiatum, Pleurotomaria sp..

Separate slipped slice near Beer Head. Rhodes also recorded historical Micraster precursor and M. cortestudinarium from a slipped chalk slice near Beer Head. Its displaced setting and the old species concepts are part of the record; it should not be merged into the four-bed Hooken bluff log.

Rowe 1903: independent Hooken sections. Rowe’s original account uses historical fossil zones rather than modern formations. His measurements and observations below belong to several different exposures. They are retained independently from the Survey’s 105 ft section and are not summed into a modern formation thickness.

Rowe: Little Beach descent interval. The air-weathered historical cuvieri-zone exposure beside the old Little Beach descent measured 16 ft from the top of the Cenomanian Limestone to the first gracilis-zone flint. This is a separate local measurement, not the 24 ft talus interval or the 14 ft fallen block farther west. The route is historical and is not recommended as open today.

Rowe: lower path bluff. The lower of two in-situ bluffs on the old ascent towards South Down Common lay well above the Four-Foot Band. It yielded large examples of the brachiopod then called Terebratulina gracilis. Its position and fauna supported Rowe’s upper gracilis-zone interpretation.

Rowe: upper path bluff. The upper bluff continued the section towards the top of the historical gracilis Zone. Its greyish apex and widely separated flints could resemble planus-zone chalk, but Rowe obtained Micraster cor-bovis there and reported no M. leskei or M. praecursor from the apex. The upper part yielded ten M. cor-bovis and one Pecten pexatus. These are source-specific occurrences and absences, not a complete local range chart.

Rowe: separate triangular surface. A small greyish-chalk surface west of and above the lower bluff yielded one Holaster planus. Rowe left its assignment between the top of his gracilis Zone and the base of the planus Zone uncertain, favouring the former. It is a separate outcrop from the two bluffs.

Rowe: three high-cliff triangles. Plates X–XI mark three further small triangular exposures with plus signs high in the main cliff. Their grey chalk and faint marl could suggest the planus interval, but Rowe used the dip and the upper path-bluff datum to favour upper gracilis-zone chalk. This was a geometrical correlation, not secure specimen dating of the three faces.

Rowe: 156 ft 3 in gracilis-zone section. With F. L. Kitchin, Rowe measured from the top of his cuvieri-zone chalk near the beach path to the apex of the upper bluff. He obtained 156 ft 3 in. This notably exceeds the Survey’s separately described 105 ft historical section. The different stations, boundaries and measurement histories are not reconciled by adding, averaging or silently replacing either value.

Rowe: lower main-cliff talus interval. At the talus east of the Beer Stone adit, Rowe measured 24 ft from the top of his Cenomanian Limestone to the first flint line, assigning that interval to the Rhynchonella cuvieri Zone.

Rowe: first flint to Two-Foot Band. At the same talus he recorded a separate 24 ft between the first flint line and the base of the Two-Foot marly band. This is only the lower part of his gracilis-zone interval, not the whole modern New Pit Formation.

Rowe: isolated block west of the adit. A displaced mass based in Cenomanian Limestone and capped by gracilis-zone chalk showed only 14 ft of the intervening cuvieri-zone package. Its reduced thickness belongs to that block and cannot be substituted for the main backscar measurement.

Rowe: cliff opposite the Tombstone. Rowe estimated about 20 ft of cuvieri-zone chalk opposite this landmark. It is an eye-estimated local thickness in the main cliff, not an additional part of the talus log.

Rowe: east of Martin’s Rock. About 250 ft east of Martin’s Rock, roughly 10 ft of cuvieri-zone chalk remained in Rowe’s account. Its rapid westward thinning was an important part of his interpretation.

Rowe: Martin’s Rock overstep. At Martin’s Rock he placed the Two-Foot Band directly on Upper Greensand, with the basal limestone, cuvieri-zone chalk and lower gracilis-zone beds omitted. Farther west the Four-Foot Band also approached the Upper Greensand as additional chalk was lost. His minimum estimate of total omitted strata was an interpretation using several reference intervals, not a directly measured missing bed.

Rowe: Mitchell’s Rock. The fallen block near the Beer–Branscombe parish boundary was described with gracilis-zone chalk on Upper Greensand and no intervening Cenomanian Limestone. It is separate from Martin’s Rock. Later correlations use the composite Branscombe/Haven surfaces and their changing relationship with the basal limestone; this preserves the distinction between observation and subsequent interpretation.

Rowe: additional exact-locality fossils. The original account confirms the 30 Echinoconus castanea collected on Hooken Beach in one day, 13 from one block. It also specifically records the cidarid historically called Cidaris clavigera on Hooken Beach, and two unnamed small spiral serpulids attached to columnals of Bourgueticrinus from Hooken. These unusually precise observations are retained without transferring Rowe’s entire pooled Devon-coast species list to this site.

Microscopic fossils: barren lower samples. Tocher’s sampled Upper Greensand and lower Beer Head Limestone at the Beer Stone Adit yielded no palynomorphs. This is a result of the particular sampled material, not proof that these seas lacked plankton.

Adit 16: first recovered cysts. Recoverable dinoflagellate cysts begin in the historical Pinnacles interval in the thesis, at sample Adit 16. That is the first productive sampled level reported, not necessarily the biological first appearance of every species.

Adit 13: Hystrichosphaeridium difficile. Sample Adit 13 contains the earliest Hystrichosphaeridium difficile found in Tocher’s local study. The primary identification is retained; the event is not asserted as a global first appearance.

Adit 11: greater cyst diversity. Tocher reports a more diverse dinoflagellate-cyst assemblage at Adit 11. No unverified species list is reconstructed from the small marks in the mixed-locality chart.

Adit 9: two named cyst events. This sample records Senoniasphaera rotundata and the last local Leberidocysta defloccata as named in the thesis. The last sampled occurrence does not by itself establish a global extinction horizon.

Adit 1: Cyclonephelium persistence. Cyclonephelium clathromarginatum persists to Adit 1 in the reported local sequence. Sample labels refer to the historical study, not to new collecting stations. Figure 40 combines several localities; only text-secured local events are reproduced here, rather than claiming a complete transcription of every matrix cell.

Geological references. De la Beche, H. T. (1826), “On the Chalk and sands beneath it … in the vicinity of Lyme Regis … and Beer”; Meyer, C. J. A. (1874), “On the Cretaceous rocks of Beer Head and the adjacent cliff sections”, Quarterly Journal of the Geological Society 30, 369–393; Jukes-Browne, A. J. and Hill, W. (1900, 1903, 1904), The Cretaceous Rocks of Britain, volumes I–III; Tocher, B. A. (1984), Palynostratigraphy of Uppermost Albian to Basal Coniacian (Cretaceous) Sediments of the Western Anglo-Paris Basin, especially Beer Stone Adit sections and figures 28 and 40; Mortimore, R. N., Wood, C. J. and Gallois, R. W. (2001), British Upper Cretaceous Stratigraphy, GCR volume 23, Hooken Cliff account; Gallois, R. W. (2004), “The stratigraphy of the Upper Greensand (Cretaceous) of south-west England”, Geoscience in south-west England 11, 21–29; Gallois, R. W. (2005), “Large-scale partial dissolution of the Chalk of the Devon coast and its engineering significance”, Geoscience in south-west England 11, 123–131; British Geological Survey (2011), South Dorset and south-east Devon and its World Heritage Coast, regional coastal Chalk discussion; Hopson, P. M. (2005), BGS Chalk lithostratigraphical framework; Rowe, A. W. (1903), “The zones of the White Chalk of the English coast, III: Devon”, Proceedings of the Geologists’ Association 18, 1–51, especially plates X–XII; Gallois, R. W. and Goldring, R. (2007), “Trace fossils at the basal Upper Greensand (Albian, Cretaceous) unconformity surface in east Devon (south-west England) and the nature of the unconformity surface”, Proceedings of the Geologists’ Association 118, 265–275; BGS (2006), Albian lithostratigraphical framework, Foxmould section; Withers, T. H. (1951), “Some Jurassic and Cretaceous crabs (Prosoponidae)”, Bulletin of the British Museum (Natural History), Geology 1, 171–186, especially pp. 179–180 and plate 16; Klompmaker, A. A., Artal, P. and Gulisano, G. (2011), “The Cretaceous crab Rathbunopon: revision, a new species and new localities”, Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 260, 191–202, figure 5B. Primary figures and historical fossil-table locality keys have been checked; unresolved historical correlations remain qualified.