Samphire Hoe Fossil Hunting

26 January 1843 – Round Down Cliff blasted for the railway
A major controlled blast created space for the Folkestone–Dover railway at the foot of the cliffs. The artificial platform, known as the Great Fall, began a long sequence of engineering changes to the shoreline now occupied by Samphire Hoe.

7 February 1844 – The cliff-foot railway opened
Completion of the railway fixed transport infrastructure below the Chalk cliffs and changed their exposure to direct marine erosion. The present landscape combines natural strata with extensive engineered ground.

1880–1881 – Early Channel Tunnel investigations
Trial tunnelling at Abbot’s Cliff was followed by boring from Shakespeare Cliff. These separate working sites on the wider coast helped establish the practical importance of the Chalk beneath the Channel; neither is a natural bed within the modern reserve.

1896–1909 – Shakespeare Colliery explored buried strata
Coal workings were developed on the site later occupied by Samphire Hoe. Coal Measures were reached deep beneath the Chalk, but flooding and other difficulties prevented commercial success. The colliery closed in 1909 after only limited production.

1969 – Cenomanian beds described in detail
Kennedy’s work refined the stratigraphy and ammonite succession between Folkestone and Dover. At the western reference sections, the numbered bands and fossil horizons remain important for recognising the Cenomanian beds.

1970–1975 – Another tunnel attempt left the access route
A tunnel through the cliff was cut in 1970 to reach the old colliery site for a renewed Channel Tunnel project. Government support was withdrawn in 1975, after an experimental drive. This engineering history underlies today’s unusual access through the cliff.

1988–1993 – The reclaimed Hoe platform created
New sea walls enclosed lagoons that were filled with chalk-marl spoil from the Channel Tunnel. By 1993 contractors’ buildings were being removed and the platform landscaped, producing the artificial ground beside the natural cliff succession.

1989–1995 – Lydden Spout marker beds correlated
Gale’s detailed studies of the nearby Lydden Spout succession identified distinctive limestone, marl and fossil horizons that could be followed across the Anglo-Paris Basin. They provided the measured framework for later climate-event research.

1994–1996 – A Middle Cenomanian climate event identified
Carbon-isotope work recognised a double-peaked excursion in the Lydden Spout succession, subsequently named the Middle Cenomanian Event 1. Fossils in the Arlesiensis and primus beds helped connect the chemical signal with incursions of cooler-water fauna.

17 July 1997 – Samphire Hoe opened to the public
The reclaimed site opened as a publicly accessible reserve. Its managed paths created a convenient approach to the west shore, while the adjacent natural cliffs retained their separate geological and tidal hazards.

2014 – Samphire Hoe Chalk included in hardening research
A study of regional Chalk hardening documented the upper Zig Zag Chalk, Plenus Marls and Holywell succession in the Samphire Hoe cliff, providing an exact-locality record of the natural bedrock above the reclaimed platform.

2022–2023 – Microfossils reveal changing sea conditions
Petrizzo and Gale’s study of Lydden Spout, published online in 2022 and in the 2023 journal volume, used planktonic foraminifera with isotope and macrofossil records to investigate the Middle Cenomanian Event. The results linked cooler-water incursions with changing water-column structure and nutrient conditions.

References
Mortimore, Wood & Gallois (2001), British Upper Cretaceous Stratigraphy, Folkestone to Kingsdown account
Petrizzo & Gale (2022 online; 2023 volume), Planktonic foraminifera document palaeoceanographic changes across MCE 1
Natural England/NCC, Folkestone Warren SSSI citation
Samphire Hoe / Getlink: Creation of Samphire Hoe
Duperret, Mortimore & Wyns (2016), La partie anglaise du bassin anglo-parisien, Bulletin d’Information des Géologues du Bassin de Paris 53(1), 15–25
Samphire Hoe / Getlink: History
Jeans et al. (2014), Regional hardening of Upper Cretaceous Chalk in eastern England
Samphire Hoe / Getlink: Visit us
Samphire Hoe existing UK Fossils guide

The natural west-shore Chalk cliffs reached from Samphire Hoe, with the separately identified Lydden Spout reference section about 500 m farther west. The reserve platform is artificial tunnel-spoil ground, not an in-situ vertical Chalk succession.

CHALK GROUP

The bedrock was deposited in a marine setting during the Late Cretaceous. Fine carbonate sediment is interspersed with clay-rich marl seams, fossil-rich horizons and surfaces recording pauses or erosion on the sea floor.

GREY CHALK SUBGROUP

The account follows the exposed succession from older to younger beds. Historic Lower, Middle and Upper Chalk divisions do not coincide with all the modern formation boundaries.

West Melbury Marly Chalk Formation

Darker marly chalk alternates with paler, harder limestone beds in regular sedimentary rhythms. The detailed lower-to-middle Cenomanian record described here belongs to Lydden Spout, about 500 m west of Samphire Hoe. The modern measured study covers about 25 m of the West Melbury–Zig Zag transition; this is not the thickness of the whole formation or of the reclaimed Hoe.

Orbirhynchia mantelliana Band 1
The lowest of three brachiopod-rich bands in the wider Abbot’s Cliff–Lydden Spout sequence lies above the paired M6 sponge limestones. Its published exposure is towards Abbot’s Cliff, farther west than the core Samphire Hoe shore; it supplies context for the younger Lydden Spout bands.

Orbirhynchia mantelliana Band 2
The middle brachiopod band occurs close above the first appearance of the ammonite Cunningtoniceras inerme in this coastal succession. It forms part of the lower Middle Cenomanian interval recognised by its combined brachiopod and ammonite fauna.

Arlesiensis Bed
A dark, fossil-rich marl lies below the lower of two prominent limestones. It contains abundant small bivalves, including Oxytoma seminudum, with serpulids and Inoceramus schoendorfi. The pectinid giving the bed its name is recorded as Chlamys arlesiensis in the recent study and under older generic combinations in earlier descriptions.

Lower prominent limestone above the Arlesiensis Bed
This conspicuous limestone directly succeeds the dark fossiliferous marl in the Lydden Spout reference sequence. It is separate from the higher Tenuis Limestone and is retained as an unnamed local marker rather than assigned an invented formal name.

Tenuis Limestone
The higher of the two prominent limestones contains the first local Acanthoceras rhotomagense. It forms a major correlation marker at the top of the West Melbury Marly Chalk, immediately below the Cast Bed of the Zig Zag Chalk.

Zig Zag Chalk Formation

Marl–limestone rhythms continue into the lower part of this formation, becoming progressively less clay-rich upwards. The lower part at Lydden Spout includes the fossil-rich Cast Bed and Middle Cenomanian climate-event record. Higher Zig Zag Chalk forms the cliff succession towards Samphire Hoe below the Plenus Marls.

Cast Bed: the primus horizon
The bed above the Tenuis Limestone contains abundant small brachiopods, including Grasirhynchia grasiana, G. martini, Kingena concinna and Modestella geinitzi. Small corals Micrabacia coronula, the bivalve Entolium orbiculare and a second abundance of Oxytoma seminudum accompany them. Rare Praeactinocamax primus links the bed with an incursion of cooler-water fauna.

Orbirhynchia mantelliana Band 3
The uppermost brachiopod band ranges through a thicker interval here than in several other southern English sections. It lies below a succession of nine conspicuous limestone bands.

Nine-limestone rhythmic interval
Above the upper brachiopod band, nine conspicuous limestones alternate with softer chalk. Each is approximately 0.12–0.20 m thick in the published coastal log. The ordinal labels below simply distinguish these successive layers; they are not formal bed names. The third to seventh harder layers lie between the sponge-rich lower bands and the higher coral-bearing Micrabacia horizon. Concinnithyris subundata is abundant through the interval and above the Micrabacia Band.

First limestone above Orbirhynchia Band 3
Discontinuous concentrations of sponges form the lowest limestone in the sequence above the upper brachiopod band.

Second limestone above Orbirhynchia Band 3
A second discontinuous sponge-rich limestone lies above the first, separated from it by softer chalk.

Third limestone above Orbirhynchia Band 3
This is the third harder layer in the nine-limestone succession.

Fourth limestone above Orbirhynchia Band 3
This is the fourth harder layer in the nine-limestone succession.

Fifth limestone above Orbirhynchia Band 3
This is the fifth harder layer in the nine-limestone succession.

Sixth limestone above Orbirhynchia Band 3
This is the sixth harder layer in the nine-limestone succession.

Seventh limestone above Orbirhynchia Band 3
This is the seventh harder layer in the nine-limestone succession.

Eighth limestone above Orbirhynchia Band 3
Abundant small corals Micrabacia coronula occur on the upper surface of this limestone. This is the Micrabacia Band, equivalent to Band 11 in Kennedy’s 1969 scheme.

Ninth limestone above Orbirhynchia Band 3
The highest limestone completes the counted succession above the upper brachiopod band, succeeding the coral-bearing Micrabacia horizon.

Jukes-Browne Bed 7
Coarse-grained chalk forms a slightly projecting layer in the higher Grey Chalk succession west of Samphire Hoe. Kennedy described a bed of laminated structures in this interval. The unit is a historical numbered bed within Zig Zag Chalk, not a formation or member.

White Bed: Jukes-Browne Bed 8
Relatively pale, less clay-rich chalk overlies Bed 7 and underlies the greenish Plenus Marls. Its contrast with those marls is conspicuous in air-weathered sections of the west-coast cliff succession.

WHITE CHALK SUBGROUP

The subgroup begins with the Plenus Marls at the base of the Holywell Nodular Chalk Formation. Older descriptions placed the Plenus Marls at the top of Lower Chalk; that historical classification differs from the modern formation hierarchy.

Holywell Nodular Chalk Formation

The formation includes the basal Plenus Marls and overlying hard, nodular chalk. The higher part is strongly condensed on the Folkestone–Dover coast and contains concentrated bivalve shell debris. Its named marker beds are not all preserved as separate layers in the way they are in expanded Sussex sections.

Plenus Marls Member

Greenish marl and chalk layers form a clear break between the White Bed below and pale, indurated chalk above. The member is visible in the Samphire Hoe cliff. Its expression varies along the coast: nearby Shakespeare Cliff and the eastern Warren preserve an eight-bed succession, whereas the immediate Hoe exposure is best recognised by its overall greenish colour and its contacts.

Holywell Nodular Chalk Formation

Above the basal Plenus Marls Member, the rest of the Holywell succession consists of hard nodular chalk and younger shell-rich beds. These belong to the parent formation, not to the Plenus Marls Member.

Hard nodular chalk above the Plenus Marls
Very hard nodular chalk above the marls initially lacks the abundant shell debris of the younger beds. This restricted interval corresponds more closely to the traditional Melbourn Rock than does the entire Holywell formation. The descriptive term does not create a separate formal member here.

Mytiloides shell-debris or Grit Beds
Fragmented bivalve shells are densely concentrated in the condensed upper Holywell succession. Air-weathered sections on the Lydden Spout cliff track display the gritty texture especially clearly. They are historical geological observations; the steep cliff path is not an alternative visitor route from the reserve.

New Pit Chalk Formation

Massive, bedded chalk with relatively few flints forms part of the higher Samphire cliff. Marl layers and basal hardgrounds distinguish this interval above the Holywell chalk.

Gun Gardens Main Marl: the Lulworth Marl boundary
This marl is used to mark the Holywell–New Pit formation boundary. The marked change from shell-rich, nodular chalk below to smoother chalk above is recorded in the Lydden Spout cliff-path section. The two names reflect alternative regional schemes for the same boundary marker.

Lewes Nodular Chalk Formation

Coarser yellowish chalk with softer marl layers, nodular hardgrounds and regular flint bands occupies the highest part of the Samphire cliff. These high-level strata are separate from the beach-level fossil exposures.

Artificial ground of Samphire Hoe
The low reserve platform was made from chalk-marl spoil excavated during construction of the Channel Tunnel and placed in enclosed lagoons. Fossils or chalk fragments in that material have been moved from their original geological position, so a find on the platform cannot automatically be assigned to the cliff bed behind it.

References

Mortimore, Wood & Gallois (2001), British Upper Cretaceous Stratigraphy, Folkestone to Kingsdown account.

Petrizzo & Gale (2022 online; 2023 volume), Planktonic foraminifera document palaeoceanographic changes across MCE 1.

Jeans et al. (2014), Regional hardening of Upper Cretaceous Chalk in eastern England.

Samphire Hoe / Getlink: Creation of Samphire Hoe.

Duperret, Mortimore & Wyns (2016), La partie anglaise du bassin anglo-parisien, Bulletin d’Information des Géologues du Bassin de Paris 53(1), 15–25.