East Runton Fossil Hunting

1882 – Runton beds documented
Clement Reid’s Geological Survey work described the local Crag and associated deposits, providing a baseline for later investigations of their fossils and relationships.

1890 – Mammal-bearing conglomerate distinguished
Reid described the occurrence of larger mammal remains in the conglomerate above the shelly Crag at East Runton, a distinction that remains important when evaluating old collections.

1953 – Fossil deer reassessed
Augusto Azzaroli’s study of Norfolk fossil deer considered East Runton material, including an extinct elk jaw reported from shelly Crag above the stone bed. Such recorded provenance helped separate specimens from the broader loose coastal assemblage.

1980 – Preglacial sequence and pollen reviewed
Richard West’s coastal synthesis described the East Runton section and its Pastonian pollen evidence. The work linked the mammal-bearing conglomerate with the overlying marine silts.

1985 – East Runton Cliffs SSSI notified
The site was notified as a distinct protected cliff and foreshore section, incorporating part of the earlier West Runton Cliffs SSSI and an extension.

1986 – Early Pleistocene voles revised
David Mayhew and Anthony Stuart’s revision of eastern English fossil voles included the East Runton Crag assemblage, strengthening its value for comparing and dating Early Pleistocene deposits.

1996 – Mixed fossil provenance examined
Adrian Lister’s stratigraphic analysis drew attention to the unusually varied deer assemblage at East Runton and the possibility that the large-mammal material represented more than one episode.

2020 – Crag fauna and chronology re-evaluated
A major study compared the East Runton molluscs and small mammals with other British and North Sea sequences. The work reinforced the need to distinguish the older shelly Crag from the overlying large-mammal-bearing conglomerate.

Local beds and displaced masses

The original order below is reconstructed from the East Runton foreshore and adjoining cliff descriptions. It is not a uniform vertical section through Wood Hill: chalk and preglacial cover were moved by ice, and modern beach sediment conceals different parts at different times.

Chalk Group

Late Cretaceous chalk occurs both as foreshore bedrock and in displaced masses. A chalk slab within till remains Cretaceous; its elevation records later movement rather than a younger depositional age.

White Chalk Subgroup

The coastal literature identifies Upper Campanian chalk along the Runton shore. Individual rafts cannot be assigned a complete regional succession from their colour or position alone.

Paramoudra Chalk Member

The East Runton–Cromer foreshore exposes chalk traditionally assigned to this division. Large cylindrical flints and ordinary flint seams are useful lithological features, but an individual flint does not identify a unique bed. No complete named-flint log has been verified for the exact East Runton collecting area, so higher Overstrand marker beds are not imported here.

Eroded Chalk surface
Where the original foreshore contact survives, the base of the preglacial sequence rests on eroded chalk. This is a major unconformity. Within a raft, a chalk–Crag contact can remain internally intact although the entire package has moved.

Crag Group

The fossil-bearing marine foreshore beds belong to the marine Crag succession, not automatically to the freshwater Cromer Forest-bed Formation.

Wroxham Crag Formation

Modern usage includes both the older Weybourne Crag and younger marine deposits formerly grouped more broadly with the Forest-bed succession. The bed descriptions below distinguish their relative positions without assigning every loose mammal fossil to one horizon.

Basal stone bed — West’s bed b
Iron-stained flint gravel occurs on the Chalk surface. This basal lag is distinct from the younger clay-pebble conglomerate above the shelly Crag.

Shelly Weybourne Crag — West’s bed c
Shelly sands and associated fine sediment overlie the stone bed. Most securely provenanced small mammals, molluscs and ostracods belong to this interval; the marine fauna indicates shallow coastal water.

Dunwich Group — intervening freshwater deposition

Freshwater sediment between the older marine Crag and the younger marine return is separated here from the marine formation.

Cromer Forest-bed Formation: freshwater interval

The freshwater muds fit the freshwater formation framework, but the cited historical account does not establish a secure modern member assignment for this exact horizon.

Freshwater muds above the Weybourne Crag
Stuart’s East Runton account records freshwater muds above the shelly Crag, with pollen assigned by West to Pre-Pastonian d. The d denotes a pollen substage here; no bed letter or thickness is inferred from it. A later marine return follows in the local record.

Crag Group — younger marine return

Marine deposition resumed after the intervening freshwater episode.

Wroxham Crag Formation: younger marine deposits

The higher conglomerate and overlying silts belong to the younger marine part of the local record.

Paston Member: higher marine interval

The Pastonian marine sediments are included in the Wroxham Crag Formation in the modern BGS coastal classification. The freshwater interlude and erosional break separate the older and younger marine records.

Erosional break above the shelly Crag
The higher conglomerate rests on an eroded surface. It must not be treated as the uppermost part of one continuously accumulated shell bed.

Clay-pebble conglomerate — West’s bed e
Ferruginous gravel contains reworked clay fragments and marine shells. Many historic antlers and elephant teeth came from this higher interval; their assemblage may combine more than one episode.

Overlying marine silts
Marine silts above the conglomerate preserve pollen attributed to Pastonian zone Pa II. This is a pollen correlation, not a numerical date applicable to all East Runton finds.

Thickness and fossil provenance

The older textbook description estimated the clay conglomerate at probably 2–3 m thick. That is a qualified historical estimate, not a current exposed thickness. The lower Crag’s small-mammal assemblage and the higher conglomerate’s large-mammal assemblage must be kept separate. No secure thickness has been recovered for every individual East Runton bed.

Albion Glacigenic Group

The cliff sequence above and around the preglacial beds has undergone intense folding, detachment and mixing. Individual depositional beds and later shear zones need to be distinguished.

Sheringham Cliffs Formation — BGS framework

The BGS framework includes the local Runton and Bacton Green tills and sand-and-gravel basins. Its regional member list is not a complete measured East Runton cliff log.

Runton Till Member

Dark grey to brown diamicton contains drawn-out sand and chalk lenses and reworked older till. A sharp basal surface can truncate marine Crag; the transition upward into Bacton Green Till is more gradational. Although the member extends to East Runton, its quoted 9 m maximum is from the Beeston-area stratotype and is not an East Runton measurement.

Bacton Green Till Member

Stony till alternates with sorted sand, silt and clay, recording a mixture of glacial sediment supply and water deposition. Later deformation can strongly alter the original layering. Its type locality is at Bacton Green; neither that section’s thickness nor every bed in it is transferred to East Runton.

Runton Cliffs Sand and Gravel Member

The unit extends between East Runton and Sheringham. Cross-bedded, rippled and channelised sand alternates with gravel and occupies basins within underlying till. Basal scour and subsequent loading complicate the geometry; the basin fill is not a laterally continuous flat cap.

Wood Hill chalk rafts and structural repetition

Historic direct observations record repeated sets of chalk beds near East Runton, with overthrust slices and folds truncated by later movement. Some masses retain Crag cappings. This evidence explains why older chalk appears high in the cliff and why a depositional chart cannot be read straight onto the cliff face.

Later structural terminology

Lee and colleagues’ 2017 framework recognises mélange and successive deformation surfaces across the Runton coast. It reorganises parts of the same glacial complex rather than adding an extra stack above the BGS members. A locally traced structural contact is needed before assigning a particular face to the alternative units.

References

Preece and colleagues (2020). Weybourne Crag palaeontology and dating, especially East Runton section3.1.1.3.
BGS. Cromer district, Sheet131.
Natural England. East Runton Cliffs citation.
Stuart (1982). Pleistocene Vertebrates in the British Isles: East Runton account.
BGS Lexicon. Runton Till Member.
BGS Lexicon. Bacton Green Till Member.
BGS Lexicon. Runton Cliffs Sand and Gravel Member.
Lee and colleagues (2017). Middle Pleistocene glacial evolution of northern East Anglia.