Heath & Reach Fossil Hunting

1925 – Quarry working begins
The quarry later known as Munday’s Hill, formerly Garside’s Pit, began working. Extraction of the industrial sands progressively exposed the tidal sediments, limestone lenses and Gault that made the site valuable for geological study.

1970 – Early palynological sampling
Kemp’s study of Aptian and Albian miospores included the northern end of Munday’s Hill Pit. This provided an early microscopic fossil record against which later sampling of the quarry could be compared.

1972 – The Gault junction is described
H. G. Owen published a detailed study of the Gault and its junction with the Woburn Sands around Leighton Buzzard, including Munday’s Hill. His numbered beds subsequently supplied the reference framework for the quarry’s nannofossil sampling.

February 1988 – A Shenley Limestone ammonite is found
P. J. Smart found a heteromorphic ammonite identified as Protanisoceras in a hard limestone lens at Munday’s Hill. Retaining its attached matrix became important when the age and possible reworking of the specimen were later debated.

1991 – Nannofossils reveal changing seas and a new species
J. A. Crux published the quarry’s 36-sample Gault nannofossil study, documenting changes in water-mass influence and an interruption between the preserved Middle and Upper Albian beds. Munday’s Hill sample 23 supplied the holotype of the newly described Owenia hilli. Another species described in the same paper, Eiffellithus monechiae, has its type specimen from Oklahoma, not this quarry.

1992 – Shenley Limestone environments are investigated
Jill Eyers’s work on Shenley Limestone sedimentology and the Lower Greensand–Gault succession developed interpretation of the contrasting shallow-water deposits. Research on the quarry’s clay drapes also provided a comparison for later palynological investigations.

Summer 1993 – A partial ichthyosaur and associated shark teeth are recovered
A damaged partial ichthyosaur was found about 4 m above the Lower Gault base on the eastern side of the quarry. Smart’s later report documented the vertebrae, other skeletal fragments and diagnostic tooth, under the historical identification Platypterygius campylodon, together with Synechodus and hexanchid teeth. Their association prompted feeding and scavenging interpretations, but it did not demonstrate a particular attack or predator.

Autumn 1993 – Quarry expansion exposes fresh Gault faces
A substantial extension stripped Gault around the north-western part of the workings, revealing fresh Lower and Upper Gault. Smart recorded the development at roughly 100 m westwards and 250 m southwards from the north-east corner. The report captures one stage in a changing quarry, rather than a surviving measured face or present access arrangement.

February 1994 – Two Lower Gault shark teeth receive specialist examination
Two Munday’s Hill teeth were examined at the Natural History Museum and reported by Smart as Anomotodon principialis and Paranomotodon angustidens, which he regarded as new records for the UK Albian. One had been found about 2 m above the Lower Gault base and the other several years earlier, but the account does not securely pair that measured horizon with either named specimen. The historical identifications and priority claim remain attributed to his report.

1994 – The ammonite’s limestone matrix is reassessed
In a report covering 1993, Smart discussed the age dispute over the 1988 Protanisoceras. He defended an indigenous occurrence in the Leymeriella regularis Subzone, using the specimen’s matrix and reported specialist examination, against a younger reworking interpretation. He also recorded that quarry expansion had destroyed the original exposure.

1994 – A detailed quarry succession is published
The Geological Survey’s Leighton Buzzard memoir documented six principal Munday’s Hill units, from Compo and Silver Sands through the Silty and Red Sands to Shenley Limestone and Gault. It retained local thickness ranges, erosional contacts and the warning that the units vary across the quarry.

1995 – The tidal-flat succession is developed
Eyers’s studies of the Silty Beds and regional Lower Greensand correlation developed the interpretation of a tidal-flat interval within the sand-to-Gault transition. The Munday’s Hill record became part of the evidence for changing sediment supply, salinity and marine influence.

August 2005 – Local geological significance is recognised
Munday’s Hill was designated a Local Geological Site for its unusually informative Lower Cretaceous succession, fossils and sedimentary structures. The designation is distinct from the neighbouring Nine Acres Pit SSSI.

2006 – Albian correlation is reviewed
A Geological Survey framework brought the Munday’s Hill junction beds and nannofossil record into a wider Albian correlation. Its local account retained the thin brachiopod-rich Shenley Limestone and overlying red Cirripede Bed as distinct horizons.

2006 – Historical Gault clay minerals are documented
C. V. Jeans included historical Munday Hill Gault samples in a broad study of Cretaceous clay mineralogy, using Owen’s bed framework. This laboratory dataset adds a separate mineralogical record alongside the quarry’s fossil-based studies. It does not use the same sample numbering or collection programme as Crux’s nannofossils.

2008 – The junction deposits receive a formal formation name
A revised Lower Cretaceous framework formally defined the Munday’s Hill Phosphatic Sandstone Formation for the phosphatic junction deposits beneath the Gault, including the Shenley Limestone Member. This clarified their place within the Lower Greensand Group while preserving the local stratotype at Munday’s Hill.

From 2008 – The lower sand exposure is obscured
Backfilling covered the formerly exposed Brown Sands, as recorded in the later local-site account. This loss of the lower exposure illustrates how quarry operations can change the available geological section without establishing closure of the whole site.

2012 – A new face is sampled for palynomorphs
Four samples were collected from a face at SP 942284 for microscopic organic-walled fossils. The material formed a separate study of the Aptian–Albian sand succession, rather than a resampling of Crux’s earlier Gault section.

2017 – Palynology refines the age of the sands
Darrin Stead and Jill Eyers published the four-sample study. Dinoflagellate cysts and sporomorphs supported a late Aptian age for the lower samples and an early Albian age for the uppermost, adding independent age evidence to the sedimentary interpretation.

2018 – A fresh Gault section is logged
Removal of Gault overburden exposed a fresh face, enabling an 11.4 m section to be logged and 20 samples to be collected for foraminiferal analysis. The new exposure provided a distinct record of the quarry’s Middle and Upper Albian mudstones.

2019 – Foraminiferal assemblages are documented
Thomas Fogerty, Malcolm Hart, Kevin Page and Christopher Smart published results from the 2018 section. The study identified 58 species among 11,345 specimens and contrasted aragonitic Lower Gault assemblages with agglutinated Upper Gault assemblages, while recognising that preservation could influence the pattern.

2020 – A later review reassesses the Gault microfossil record
Hart, Fogerty and Smart published an updated study of Gault foraminifera that revisited the Munday’s Hill section opened in 2018. They recorded that Shenley Limestone was not visible during that investigation and placed the quarry’s change from aragonitic to more agglutinated and planktonic assemblages within a wider regional discussion of preservation, sea level and palaeogeography. The publication adds interpretation of the existing section; it does not document a new quarry sampling programme in 2020.

28 April 2025 – A restoration-related recovery permit is issued
A permit for depositing waste as a recovery operation was issued to FOX (OWMBY) LIMITED for Munday’s Hill Quarry. It records authorisation of recovery operations within the working landscape; it does not itself establish visitor access or the closure of every part of the quarry.

Locality and measured-section scope
Munday’s Hill is a changing quarry, not a single permanently exposed section. The 1994 Geological Survey account at SP 937282 records six principal units and warns that they are not present everywhere. The thicknesses below retain its qualifiers: a maximum, a range and a thickness “seen” have different meanings. They must not be added into one complete column. Crux’s Gault samples at SP 939279 and the later palynological face at SP 942284 are separate observations, as is the formal phosphatic-sandstone stratotype at SP 93942798. The local-site form describes several faces around 50 × 15 m, varying with the workings; its May 2025 condition assessment was unknown, so those dimensions do not establish the size or availability of a face today. The Survey described up to 16 m of overburden, comprising 6 m of till and up to 10 m of Gault. This is historical overburden context, not a reason to add every maximum in the succession into one measured column.

LOWER GREENSAND GROUP

Woburn Sands Formation

Age, environment and descriptive sand names
In the wider Bedfordshire region, late Aptian marine inundation spread across an eroded older landscape, producing a shallow, strongly tidal seaway. The Woburn Sands are quartz-rich, locally glauconitic sands of Aptian–Albian age. Their full regional thickness is not exposed at Munday’s Hill. Brown, Silver, Silty and Red are useful historical quarry names for variable lithologies; the Survey did not adopt them as four mappable formal formations. Cross-beds are inclined layers formed by migrating sand bodies and should not be mistaken for the regional structural dip.

Compo / lower Brown Sands: seen to 5 m
The lowest unit in the 1994 Munday’s Hill table is “Compo”, seen to 5 m: very fine-grained, grey-white silty sand with glauconite speckles, cross-bedding and numerous wavy grey silty-clay partings. Trace fossils and boxstone nodules are recorded. Its fine grain size and silt content limited its industrial value. The later local-site description calls the lowermost estuarine unit Brown Sands and records its exposure as obscured by backfill from 2008. The leaflet’s upper 4 m and the table’s 5 m seen refer to observations of the local lower sands, not their total regional thickness.

Silver Sands: 4–10 m
The recorded Silver Sands are 4–10 m of white, medium- to coarse-grained sand with quartz and chert granules or small pebbles up to 5 mm across. Well-developed planar cross-bedding and abundant lignitic wood are characteristic. Their irregular, undulating base carries a layer of boxstone nodules in clay. Towards the top, ochreous staining is associated with ferruginously cemented sandstone bodies known as carstone reefs. These details belong to the measured Munday’s Hill record; larger thicknesses reported elsewhere around Leighton Buzzard do not replace the local range.

Tidal structures, burrows and sand sorting
The local-site account interprets the Silver Sands as estuary-mouth bars and records bidirectional tidal bundles, ripples with mud drapes, ripple cross-lamination, channels and higher-energy granule layers. These show alternating energetic sand transport and quieter intervals when fine mud could settle. Trace fossils document occupation of the sediment between depositional events. The exceptionally clean quartz sands were an important industrial resource; their sorting is part of the geological story rather than evidence that all the beds formed at the same time or under identical currents.

Carstone reefs and lateral changes
Carstone reefs are linear bodies of iron-cemented Silver Sands, not biological reefs. The 1994 quarry discussion describes bodies 10–25 m across and 2–3 m high, whereas the caption to its Munday’s Hill photograph gives 3–10 m width and 2–3 m height. These are separately reported dimensions of variable cemented bodies, not a single bed thickness. The memoir relates their position to the edges of surviving Silty Beds banks: cleaner white sand remained beneath those banks, while more iron-stained sand occurs where Red Sands directly overlie Silver Sands. Long lateral continuities reported across the Shenley Hill workings should not be treated as a surveyed modern face at Munday’s.

Silty Beds: up to 4.5 m
The Silty Beds reach up to 4.5 m in the local table. They are very fine-grained, silty and clayey sands with wavy partings of dark grey silty clay, sporadic pockets of coarse grit and boxstone nodules. Their finer sediment, organic material and changing sand–mud alternations record tidal-flat conditions. Freshwater algae reported in the quarry leaflet indicate freshwater input, while marine influence is also present: the succession records changes in salinity, not a wholly freshwater deposit.

Red Sands: up to 4 m in the historical table
The historical Red Sands row comprises up to 4 m of medium- to coarse-grained cross-bedded sand. Concentrations of goethite grains form thin dark bands, giving the sand a striped appearance and highlighting the inclined bedding. Its contact cuts markedly into both the Silty Beds and the Silver Sands. Consequently, the presence or absence of the fine silty interval can change laterally. The wider district includes thicker Red Sands and other burrowed facies, but those measurements and trace-fossil identifications are not assigned automatically to Munday’s Hill.

Munday’s Hill Phosphatic Sandstone Formation

Phosphatic junction deposits and modern boundaries
The modern formation encompasses the phosphatic junction deposits formerly described as Junction Beds or Transition Series. At its Munday’s Hill stratotype the formation is up to 2.5 m thick, with poorly cemented ferruginous sandstone and clayey, glauconitic, phosphatic sandstone or sandy mudstone. Carstone and boxstone fragments, phosphatic concretions and worn or reworked fossils occur in discrete horizons. Its base is an unconformity above Woburn Sands; its upper non-sequence is commonly marked by a phosphatic nodule–pebble horizon beneath smoother Gault mudstone. This formal definition is distinct from the descriptive 4 m Red Sands row in the 1994 table, so the two should not be equated wholesale.

Shenley Limestone Member

Lenticular brachiopod limestone: up to 0.1 m in the local table
The local table records up to 0.1 m of pale-brown phosphatic limestone with limonite and glauconite grains and many brachiopods locally. It forms discontinuous lenses associated with iron-rich beds, rather than a continuous limestone sheet. Modern classification places it within the Munday’s Hill Phosphatic Sandstone Formation. The formation’s wider BGS Lexicon description mentions limestone around 0.6 m thick in the stratotype area and nearby localities, whereas the exact quarry table and separate Shenley member entry support the 0.1 m figure used here. Its upper-boundary description also mentions about 1.2 m of Cirripede mudstone in some places, compared with up to 0.3 m in the historical Munday’s Hill table. These differently scoped figures are retained as source comparisons; they do not replace or enlarge the quarry’s recorded rows.

Marine fauna, condensation and reworking
The limestone records fully marine conditions during a condensed interval of limited sediment accumulation. In the Shenley Hill area, limestone and gritty ironstone formed over remnant banks of the Silty Beds, while different sandy and glauconitic junction facies developed alongside them. Reworking could mix older limestone fragments and fossils into younger sediment. The regional brachiopod-rich facies explains the local character, but a fossil list from another Shenley Hill pit is not automatically a Munday’s Hill occurrence list.

A specimen-specific age debate
A Protanisoceras specimen found by P. J. Smart in February 1988 became part of a debate over the limestone’s age. In his report for 1993, published in 1994, Smart argued that its dense, in-situ limestone matrix supported the Leymeriella regularis Subzone, in contrast to Eyers’s younger Cleoniceras floridum interpretation. He recorded the specimen 4 cm above the basal cortex of a hard lens and stated that later quarry expansion removed the exposure. This is an attributed interpretation of a particular specimen and lens, not a basis for assigning every Shenley Limestone occurrence to one subzone.

SELBORNE GROUP

Gault Formation

Gault mudstones and the basal Cirripede Bed
The 1994 quarry table records up to 10 m of bluish, greenish and black colour-banded mudstone, with common fossils and bands of phosphatic nodules. Locally near the base lies brick-red mudstone, the Cirripede Bed, up to 0.3 m thick in this exact record. The pale-brown limestone below and this red clay above are different rocks and should not be combined into one fossil bed. The 10 m figure is a historical quarry exposure maximum; the later 11.4 m foraminiferal section represents a different face and sampling episode.

Phosphatic and fossil-rich horizons
Phosphatic nodules and fossil-rich layers reflect pauses in accumulation, concentration and some reworking on the seabed. The 2025 local-site account identifies the varicosum band as especially fossiliferous, named for its characteristic ammonite. It also records a broad marine fauna including molluscs, crustaceans and vertebrate remains. This local horizon-level observation is more useful than assuming that each species occurs throughout the whole mudstone succession.

Historical Lower Gault exposures and a crab voucher
Smart’s report for 1993, published in 1994, records an autumn expansion that stripped Gault roughly 100 m westwards and 250 m southwards from the north-east corner, opening fresh Lower and Upper Gault faces. These are dimensions of historical quarry development, not bed thicknesses or a present route. His illustrated Munday’s Hill crab, collection number 14813 M, is an incomplete cephalothorax from the Lower Gault dentatus Zone at SP 936279, recorded as Notopocorystes (Notopocorystes) stokesii stokesii. The names and collection numbers in this historical register follow Smart’s report and do not imply a fresh modern taxonomic revision.

Two illustrated Lower Gault shark teeth
Smart figured an upper anterolateral tooth as Anomotodon principialis, collection 15088 M, and an upper anterior tooth as Paranomotodon angustidens, collection 15325 M, both from Munday’s Hill’s Lower Gault. The pair was examined at the Natural History Museum in February 1994; Smart reported them as new records for the UK Albian at that time. One tooth had been found in place about 2 m above the Lower Gault base, while the other had been collected several years earlier from the quarry’s Hoplites dentatus Zone. The account does not unambiguously identify which named specimen belongs to the 2 m horizon, so that measurement is not attached to either voucher.

The partial ichthyosaur found in summer 1993
A damaged partial ichthyosaur was recovered from the eastern Lower Gault face, approximately 4 m above its base. Smart described three complete but cracked thoracic vertebrae, fragments of skull, ribs and paddle, a reasonably preserved ulna and a tooth. Figure 5 identifies the illustrated tooth as Platypterygius campylodon, collection 15188 M, from the Euhoplites loricatus Zone at SP 936279. This is the report’s historical tooth-based identification; it is not presented as a newly verified modern species determination, a complete skeleton or an estimate of the animal’s length.

Associated shark teeth and the limits of the feeding interpretation
Three teeth recorded as Synechodus recurvus accompanied the ichthyosaur, including illustrated specimen 15187 M. Two hexanchid lower-jaw lateral teeth were also associated: a serrated example named Notorhynchus aptiensis, collection 15191 M, and an undetermined example with an unserrated acrocone, collection 15190 M. The report places these in the loricatus horizon and notes two earlier similar undetermined teeth from approximately the same stratum. Smart discussed feeding or scavenging to explain the association, but the teeth themselves do not establish a demonstrated kill or scavenging event. He attributed breakage to machinery and considered an attack by Polyptychodon only speculatively; the account supplies neither a local voucher of that reptile nor demonstrated bite marks on this skeleton.

A nautiloid above the Gault junction
Smart recorded a small Eutrephoceras clementinum about 1.5 m above the junction bed in the Lower Gault Hoplites spathi Subzone. He compared it with his own earlier individual from farther west in the same quarry and cited his 1957 report. These are two finds known to that recorder, rather than a count of all nautiloids from the locality; 1957 is the date of the cited report, not an independently verified collection date.

Crux’s 1991 Gault study: sampling and preservation
Crux studied 36 samples numbered 11–46 from the Gault section at SP 939279. The lowest, sample 11, was barren of nannofossils; the other 35 yielded productive assemblages. The Methods section reports 39–54 species per productive sample, whereas the later discussion reports 59 species in the niobe interval. This internal numerical discrepancy is retained as published, rather than silently choosing one value. All showed some etching and the higher samples included secondary calcite overgrowth. Samples 27–29 were less well preserved. High abundance of Watznaueria barnesae in samples 33–34 accompanied low diversity, but sample 22 contained about 50 species despite similarly high abundance, so one abundant taxon alone is not a complete preservation test.

Ammonite zones and the major hiatus
In the ammonite scheme used by Crux, the sampled section runs from the Hoplites dentatus Zone into the Mortoniceras inflatum Zone. The very lowest dentatus interval was not sampled. A hiatus removes the upper part of the Euhoplites loricatus interval, all of the Euhoplites lautus Zone and the lowest part of inflatum; the Stoliczkaia dispar Zone is absent from the studied section. These are gaps in this historical record, not proof that every later quarry face exposes exactly the same limits. The original zonal language is retained rather than silently recast into a newer scheme.

Nannofossil age schemes and correlation
Crux placed the section between the first appearances of Tranolithus orionatus and Eiffellithus turriseiffeli in the nannofossil succession. He correlated it with the upper Prediscosphaera cretacea Zone, zone 8b and NC8–9 in different published schemes. These are source-era alternative biozonations, not extra beds to insert into the quarry log.

How to read the historical bed–sample record
The following sample assignments follow Crux’s Appendix 1, which explicitly uses Owen’s 1972 bed numbering. They describe where the nannofossil samples were taken; they do not supply the full lithological log of every Owen bed. Samples 13–41 were spaced at approximately 30 cm, while samples 41–46 were spaced at 120 cm; sample 41 is the shared endpoint. This sampling spacing must not be turned into an exact thickness for each bed.

Owen bed 1: samples 11–12
Sample 11 came from the base of bed 1 and was barren of calcareous nannofossils. Sample 12 came from the top of bed 1 and was productive. These two positions retain the original basal and upper qualifiers without implying a measured thickness for the whole bed.

Owen bed 2: samples 13–19
Sample 13 was assigned to bed 2(ii), sample 14 to bed 2(iii–iv), and sample 15 to near the base of bed 2(v). Samples 16, 17 and 18 also came from bed 2(v), with sample 19 near its top. All are in the productive part of the nannofossil dataset.

Owen bed 3: samples 20–23
Sample 20 was assigned to bed 3(ii) with a question mark; that uncertainty is retained. Sample 21 came from bed 3(iii), sample 22 from bed 3(iv), and sample 23 from bed 3(v). Sample 23 provided the holotype of Owenia hilli from the Upper Gault cristatum Subzone. The neighbouring sample numbers should not be read as a continuous record across the sedimentary hiatus.

Owen bed 4: samples 24–30
Samples 24 and 25 represent the lower and upper parts of bed 4(i); sample 26 is from 4(ii), and sample 27 from 4(iii). Samples 28 and 29 came from near the base and near the top of 4(v), respectively, while sample 30 was assigned to 4(ix). These are the sub-bed divisions actually represented in the sample list; the skipped numerals are not permission to invent missing sample horizons. Samples 27–29 have the poorer preservation noted by Crux.

Owen bed 5: sample 31
Sample 31 is assigned to bed 5. It is one productive sampling point, not an independent measurement of the full thickness, lithology or faunal range of that bed.

Owen bed 6: samples 32–46
Samples 32–46 are all assigned to bed 6. The list comprises samples 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45 and 46. Sampling is approximately 30 cm up to sample 41, then 120 cm between the higher samples. The coarser spacing is a feature of the research design, not a newly defined geological subdivision of bed 6.

Selected abundance curves: warmer-water and other taxa
Crux’s first abundance figure plots Rhagodiscus achlyostaurion, R. asper, R. splendens, Prediscosphaera cretacea and Lithastrinus sp., alongside sample richness. The three Rhagodiscus curves show related changes, interpreted as a possible preference for warmer surface waters. The Prediscosphaera pattern was less straightforward and may have reflected nutrient conditions. These curves are a selected set of measured taxa, not the whole species-by-sample inventory.

Selected abundance curves: changing water-mass influence
The second abundance figure plots Repagulum parvidentatum, Tranolithus orionatus, Rhagodiscus angustus, Seribiscutum primitivum and Staurolithites matalosus. The changing proportion of higher-latitude forms, especially Repagulum and Seribiscutum, was used to infer relatively cool-water influence near the early Middle Albian and again at the base of the preserved Upper Albian. Lower-latitude forms persisted too, indicating continuing marine connections. These are assemblage-based palaeoceanographic interpretations, not direct numerical temperature measurements. Repagulum parvidentatum was common or abundant through the Middle Albian and the basal preserved Upper Albian cristatum interval, and became common again in sample 45. Crux therefore rejected its last common occurrence as a dependable single dating horizon: recurrence and diachronous changes complicate that signal.

Local nannofossil range events
Within this section, Axopodorhabdus albianus first appears in the niobe Subzone, while Owenia hilli is recorded in the preserved Upper Albian above the break. Corollithion signum first occurs in the cristatum interval, but Crux warned that identification differences and rarity limit its precision. Tegulalithus tessellatus first occurs in the varicosum–auritus interval, while Eiffellithus monechiae was recorded in samples 45 and 46 of that higher interval. Local first occurrences are not automatically the evolutionary first appearances of those species everywhere.

Other local occurrences and preservation cautions
Braloweria boletiformis has its last observed occurrence in sample 21, near the intermedius–niobe boundary, and Hayesites albiensis disappears in the local niobe interval. Ceratolithina hamata and Gaarderella granulifera occur in both Middle and Upper Albian samples. A rare form recorded provisionally as Crepidolithus sp. was seen only by light microscopy in one sample; Crux found no other evidence for reworked Jurassic nannofossils and did not treat this resemblance as proof of Jurassic contamination. Appendix 2 lists species considered in the study and must not be used as a blanket local occurrence list.

How the historical nannofossil groups were counted
The light-microscope Lithastrinus orbiculatus group includes Lithastrinus floralis. Crucibiscutum hayi and Crucibiscutum salebrosum were counted together, while Ceratolithina cruxii was included with Ceratolithina hamata. The forms called Calculites sp. 1 and sp. 2 retain their tentative generic assignment. Such combined or provisional records should not be split into invented independent counts or silently rewritten as accepted modern species. Crux also noted that his Prediscosphaera cretacea probably included P. columnata, because the distinguishing spines were often not preserved. This remains a probable grouping in that study, rather than an additional independently counted local species.

Explicitly absent comparison taxa
Crux did not observe Braloweria judithae, Biscutum dissimilis or Sollasites falklandensis at Munday’s Hill and explicitly described Rucinolithus irregularis as absent. They belong in the discussion of comparison and absence, not in a list of local finds. Their occurrence in the paper’s wider taxonomic or palaeogeographical discussion does not override those statements.

Local illustrated specimens and measured microfossils
The plates document the tentative Calculites sp. 1 from samples 39 and 12, sp. 2 from sample 23, and Crucicribrum anglicum from samples 12 and 31. The local diagnosis of Owenia hilli reports lengths of 2.9–3.5 µm and widths of 2.0–2.1 µm for two measured specimens, not a broad population-size distribution. Its sample 23 holotype is local, whereas the type and associated measurements of Eiffellithus monechiae in the same paper are from Duck Creek, Oklahoma.

The full plotted historical nannofossil register
Figures 5–7 plot 88 taxon or combined-group columns from the Munday’s Hill samples. The register below retains those historical column names, including uncertain identifications and grouping. It is neither a count of 88 currently accepted species nor a numerical transcription of every range or abundance cell. Appendix 2 has been used only to expand abbreviated names already evidenced in the local figures; it is not imported wholesale as a locality list.

Historical register: Figure 5, columns 1–14
Corollithion achylosum; Rhagodiscus achlyostaurion; Bukrylithus ambiguus; Crucicribrum anglicum; Rhagodiscus angustus; Rhagodiscus asper; Watznaueria barnesae; Braloweria boletiformis; Lithraphidites carniolensis; Glaukolithus compactus; Cretarhabdus conicus; Cretarhabdus crenulatus; Prediscosphaera cretacea; Staurolithites crux.

Historical register: Figure 5, columns 15–28
Axopodorhabdus dietzmannii; Biscutum ellipticum; Zeugrhabdotus embergeri; Zeugrhabdotus erectus; Lapideacassis glans; Hemipodorhabdus gorkae; Gaarderella granulifera; Discorhabdus ignotus; Cylindralithus laffittei; Chiastozygus litterarius; Cretarhabdus madingleyensis; Staurolithites matalosus; Grantarhabdus meddii; Zeugrhabdotus noeliae.

Historical register: Figure 6, columns 1–16
Lithastrinus orbiculatus group; Tranolithus orionatus; Watznaueria ovata; Repagulum parvidentatum; Manivitella pemmatoidea; Lithastrinus sp. cf. L. planus; Seribiscutum primitivum; Octocyclus reinhardtii; Cyclagelosphaera rotaclypeata; Rhagodiscus splendens; Tegumentum striatum; Calculites sp. 1; Hayesites albiensis; Cretarhabdus angustiforatus; Tetrapodorhabdus coptensis; Grantarhabdus coronadventis.

Historical register: Figure 6, columns 17–32
Scapholithus fossilis; Corollithion geometricum; Crucibiscutum hayi / Crucibiscutum salebrosum; Sollasites horticus; Corollithion rhombicum; Zeugrhabdotus sisyphus; Watznaueria britannica; Cyclagelosphaera margerelii; Flabellites oblongus; Prediscosphaera spinosa; Calculites sp. 2; Watznaueria biporta; Microstaurus chiastius; Haqius circumradiatus; Sollasites lowei; Lapideacassis mariae.

Historical register: Figure 7, columns 1–14
Cretarhabdus striatus; Chiastozygus sp.; Lithastrinus planus; Cretarhabdus inaequalis; Helicolithus trabeculatus; Nannoconus spp.; Axopodorhabdus albianus; Ceratolithina hamata; Braarudosphaera africana; Braarudosphaera bigelowii; Percivalia fenestrata; Owenia hilli; Tranolithus gabalus; Corollithion signum.

Historical register: Figure 7, columns 15–28
Viminites swinnertonii; Reinhardtites brooksii; Gartnerago praeobliquum; Rhagodiscus infinitus; Tegulalithus tessellatus; Nannoconus truittii; Nannoconus minutus; Cribrosphaera ehrenbergii; Lithastrinus sp.; Nannoconus elongatus; Staurolithites angustus; Crepidolithus sp.; Truncatoscaphus sp. cf. T. delftensis; Eiffellithus monechiae.

The separate 2012 palynological samples
Four samples collected in 2012 from the face at SP 942284 were analysed for organic-walled palynomorphs and published by Stead and Eyers in 2017. Their accessible account records diverse dinoflagellate cysts and sporomorphs, including Kiokansium unituberculatum, Cerbia tabulata, Aptea polymorpha and Cyclonephelium inconspicuum. The lower samples indicated a late Aptian age and the uppermost an early Albian age. These four samples concern a different part of the succession and a different face from Crux’s Gault nannofossils; no complete four-sample range table is reconstructed here.

The separate 2018 foraminiferal section
A fresh Gault face exposed in 2018 was logged over 11.4 m and sampled 20 times for foraminifera. Fogerty and colleagues reported 58 species among 11,345 specimens in 2019, spanning the Hoplites spathi to Hysteroceras varicosum subzones. Lower Gault assemblages contained abundant aragonitic foraminifera, whereas agglutinated forms dominated the Upper Gault. The authors considered ecological controls such as water depth but could not rule out preservation effects. This is a separate measured dataset; its full species list and sample table are not substituted by Crux’s records or by other regional sections.

The 2020 review of the refreshed Gault face
Hart, Fogerty and Smart’s 2020 review revisited the 11.40 m Gault section made available in 2018 at SP 93427 27985. They reported that Shenley Limestone was not visible during that study, illustrating how a well-documented fossiliferous unit may be unavailable in a particular face. This observation does not establish permanent absence from the quarry. Their historical summary describes five subdivisible Gault beds, whereas Crux’s Appendix 1 assigns samples to Owen beds 1–6. Those source-specific counts are retained without forcing a one-to-one renumbering or reconstructing the unavailable full Owen log.

A later description of the Middle–Upper Albian break
The 2020 review names the Daviesi and Nitidus subzones as missing in its description of the gap between Niobe and Cristatum. The same passage also describes a break above the Intermedius Subzone. These formulations preserve the complexity of that published correlation; they are kept separate from Crux’s source-era zonal wording rather than treated as extra physical beds or silently combined into a new local log.

Foraminiferal preservation and changing sea conditions
The later authors included Munday’s Hill in a regional pattern of abundant aragonitic Lower Gault foraminifera followed by more agglutinated and planktonic forms higher in the succession. Their regional planktonic examples are Muricohedbergella delrioensis, M. infracretacea and M. planispira; they explicitly include the Munday’s Hill upward-increasing trend and cite Fogerty’s 2019 figure. These names are comparative examples in that review, not a recovered quarry species-by-sample table or identifications of the guide’s photographs. Mudstone compaction, grain size and selective loss of aragonitic tests complicate the ecological signal. The authors considered deepening and a regional marine flooding episode, without supplying a numerical water depth for Munday’s Hill.

Quaternary till and derived fossils
Up to 6 m of blue-grey and grey-brown chalky, flinty till was recorded above the Gault at a sharp, planar contact. This glacial deposit is much younger than the Early Cretaceous bedrock. Worn Gault fossils can be incorporated into it by erosion and transport, so a marine fossil found in till records reworking rather than a Quaternary sea at the quarry. The cap and later quarry backfill can hide or remove access to parts of the bedrock succession.

References

Shephard-Thorn, E. R., Moorlock, B. S. P., Cox, B. M., Allsop, J. M. and Wood, C. J. (1994). Geology of the country around Leighton Buzzard. British Geological Survey memoir, sheet 220. Munday’s Hill section, informal Woburn Sands units, Gault and Quaternary accounts.
Owen, H. G. (1972). The Gault and its junction with the Woburn Sands in the Leighton Buzzard area, Bedfordshire and Buckinghamshire. Proceedings of the Geologists’ Association, 83, 287–312. Bed numbering used in Crux’s Appendix 1; the full original bed descriptions are not reproduced here.
Crux, J. A. (1991). Albian calcareous nannofossils from the Gault Clay of Munday’s Hill (Bedfordshire, England). Journal of Micropalaeontology, 10, 203–222, especially Figures 2–7 and Appendix 1.
Smart, P. J. (1994). Geology and Palaeontology: Report of the Recorder. Bedfordshire Naturalist for 1993, 48, 10–18. The volume’s reporting year is 1993; its publication year is 1994.
Wilkinson, I. P. (2006). The holostratigraphy of the Albian Stage (Lower Cretaceous) of the United Kingdom and its continental shelf. British Geological Survey Research Report RR/06/01, especially §6.8.3.
Hopson, P. M., Wilkinson, I. P. and Woods, M. A. (2008). A stratigraphical framework for the Lower Cretaceous of England. British Geological Survey Research Report RR/08/03, especially §5.17.
BGS Lexicon: Woburn Sands Formation; Munday’s Hill Phosphatic Sandstone Formation; Shenley Limestone Member.
Stead, D. and Eyers, J. (2017). The palynology and geology of the Lower Cretaceous (Aptian–Albian) of Munday’s Hill Quarry, Bedfordshire, UK. Proceedings of the Geologists’ Association, 128, 599–612. DOI: 10.1016/j.pgeola.2017.05.011. Summary based on the publisher abstract and accessible excerpts.
Fogerty, T., Hart, M. B., Page, K. N. and Smart, C. W. (2019). The foraminiferal biostratigraphy and paleoenvironmental interpretation of the Gault Clay Formation (Middle and Upper Albian) at Munday’s Hill Quarry, Bedfordshire, UK. Micropaleontology, 65(6), 485–511. DOI: 10.47894/mpal.65.6.02. Summary based on the publisher abstract.
Hart, M. B., Fogerty, T. and Smart, C. W. (2020). Foraminifera of the Gault Clay Formation: An update. Proceedings of the Geologists’ Association, 131, 386–396. Exact quarry account in §3.2 and regional preservation/palaeoecological discussion in §§5–6. Author manuscript dated 28 September 2019; final publication 2020.
Jeans, C. V. (2006). Clay mineralogy of the Cretaceous strata of the British Isles. Clay Minerals, 41(1), 47–150. Historical Munday Hill samples appear in Table 23o; mineral-code values are not reproduced here.
Bedfordshire Geology Group (2025). Munday’s Hill Quarry Local Geological Site designation form, revised May 2025; and Lower Greensand: Munday’s Hill Quarry, educational leaflet. The leaflet’s Silver Sands photograph is from Stone Lane Quarry, and its older numerical age scale is not used here.