Lee Bay Fossil Hunting

1839 – Early structural observations around Lee
Henry De la Beche described the grey fossil-bearing succession along this coast and singled out the coves on either side of Lee as useful places to see the true dip. He cautioned that undulations along the direction of the beds could be mistaken for their inclination, an important distinction when interpreting the coastal exposures.

1841 – Lee Cove included in an early fossil succession
John Phillips explicitly included the cliffs of Lee Cove in his account of the middle part of the Linton Group, alongside the Valley of Rocks. This established the cove’s place in an early systematic description of north Devon’s fossiliferous rocks. His approximate 500 ft thickness referred to the combined middle-division account, rather than a separate measured section of this bay.

1911 – Marine erosion linked to the shape of Lee Bay
Edward A. Newell Arber described fossil-bearing Lynton rocks at Lee Mouth near Lynton and interpreted Lee Bay as an enlarged stream mouth cut back by the sea, with Duty Point and Crock Point flanking it. His discussion made the relationship between drainage and coastal erosion central to understanding the bay.

1953 – A former river route proposed through Lee Abbey
Scott Simpson interpreted the coastal dry-valley remnants as parts of an older westward course of the East Lyn, including the Lee Abbey gap. This was a specific reconstruction of the drainage before marine erosion broke it up, rather than a fossil discovery or a directly dated event.

1966 – An ice-marginal drainage alternative
N. Stephens proposed that glacial ice along the north Devon coast could have diverted drainage into marginal channels. This provided a competing explanation for the dry-valley system associated with the Valley of Rocks and Lee Abbey, and made the origin of the coastal deposits especially important to the debate.

1980 – Lee Bay section and buried valley investigated
D. Dalzell and E. M. Durrance combined a description of Lee Bay’s raised-platform sediments with electrical-resistivity investigation of the buried valley fill. Their work separated a lower waterlain succession from overlying angular head and argued that the Lee Abbey gap had carried a tributary rather than the main East Lyn. Marine capture of that tributary provided an explanation for the present bay.

1985 – A precisely located fossil assemblage documented
The geological resurvey published a collection from the Lee Bay reef at SS 6937 4919, recording qualified brachiopod and bivalve identifications, crinoid columnals and borings. The accompanying coastal account also documented head above rounded gravel and proposed a glaciofluvial interpretation for the lower deposit, preserving an important alternative to the raised-beach explanation.

1986 – Coast and geological exposures protected
The West Exmoor Coast and Woods Site of Special Scientific Interest was notified in 1986, covering the coastal landscape containing Lee Bay. The designation protects a combination of geological and biological interests, with the bay’s exposures forming part of the wider conserved coastal setting.

1995 – The reef placed within a sedimentological framework
Christopher John Pound correlated the precisely located Lee Bay reef collection approximately with an informal upper-middle subdivision of the Lynton Formation. This connected its fossil record with a wider reconstruction of the Devonian depositional system while leaving its position an approximate correlation rather than a newly measured or formally named bed.

1998 – The four-bed coastal record synthesised
The bay’s Pleistocene deposits were brought together in a major geological conservation assessment. The account retained four distinct beds above the rock platform and explained how the association of waterlain deposits and head contributes to the relative dating of coastal erosion and abandoned drainage routes.

2021 – Lee Bay’s additional geological interest retained
A review retained Lee Bay as a Local Geological Site because of its good Lynton Formation exposures, even though it already lay within a wider area recognised for Quaternary interest. This preserved the distinction between the bay’s Devonian bedrock value and its much younger coastal and valley deposits.

Lynton Formation

The bay’s bedrock belongs to the Emsian–Eifelian Lynton Formation. The current Lexicon assigns no parent group, and no formal member subdivision is established here. Lynton Beds, Lynton Slates and the historical Linton Group describe the older nomenclature, rather than extra units to stack above or below the formation. The base is not seen regionally; the upper transition to the Hangman Sandstone Formation is documented at other coastal sections, not as a complete exposed boundary within this guide’s bay.

Sandstone-rich beds and interbedded slaty intervals
A sandstone-rich division can be followed from west of Crock Point through the Lee Bay area towards the Valley of Rocks. The local succession combines more resistant sandstones with finer, slaty material. The broader formation contains fine sand–mud lamination, burrowed intervals and thin shell-bearing layers, but regional bed thicknesses cannot be transferred to this bay as a numbered log. The available exact-bay evidence does not securely correlate individual Devonian beds into a continuous measured column.

Fossil-bearing reef: survey locality C
The precisely located collection is from the Lee Bay, Martinhoe reef at SS 6937 4919, with specimens numbered DEA 1200–1226. All six fossil occurrences in the published table are retained here: ?Chonetes sarcinulatus; an indeterminate strophomenoid; an indeterminate spiriferacean; ?Prothyris plicata; crinoid columnals; and indeterminate borings. The first and fourth identifications carry question marks in the source. This is a sampled assemblage at a mapped point, not a formal named bed or an abundance survey of the whole beach. Fossils recorded at Wringcliff Bay, Woody Bay, Crock Point and the Valley of Rocks are not automatically Lee Bay records.

Approximate correlation within the sandstone-rich succession
Pound subsequently placed the same survey locality C approximately within his informal upper-middle mega-facies. This is a sedimentological correlation of the sampled reef, not a formally named member or a measured thickness for the beach. The published diagram explicitly warns that its relative-age axis is not an evenly spaced time scale. Detailed logs from Lee Stone near the outer Duty Point and from west of Crock Point should not be presented as a continuous measured section of the inner bay.

Historical middle division and thickness limitation
Phillips placed the cliffs of Lee Cove together with the Valley of Rocks in his “middle part” of the Linton Group. His approximately 500 ft description concerns that combined account. It neither measures an isolated 152 m succession at Lee Bay nor defines a modern member. Several old names reproduced in later collecting guides, including Turbinolopsis pluriradialis, Spirifera ostiolata, Spirifera aperturata, Orthis granulosa and Orthis sordida, occur in his Valley of Rocks narrative; that passage does not establish that they are all common finds in this bay. They are historical determinations, not a revised modern identification list.

Bedding, cleavage and local structure
The Lee Bay area at approximately SS 692 492 has recorded bedding inclinations of 17–29°. These readings belong to the local coastal area within the Lynton Anticline and are not a uniform dip for every rock surface. Cleavage should be distinguished from bedding; the difference is especially important when following fossil-bearing layers through slaty rocks. Historical observers already noted that undulations along the strike of this coast could be mistaken for the true dip.

Pleistocene coastal deposits

These unconsolidated deposits are separate from the Devonian formation. The numbered sequence below is the four-bed Lee Bay section described by Dalzell and Durrance and reproduced in the Geological Conservation Review. It is listed from top to bottom. The stated figures are approximate maximum bed thicknesses; they should not be added and presented as a single measured total at one point.

Bed 4: angular head, maximum about 18 m
Coarse angular rock fragments with some subrounded pebbles overlie the waterlain gravel succession. This head records slope-derived material; cold-climate frost breakdown and downslope movement are central to its interpretation. Its angular debris contrasts with the more rounded material below. It is not a Devonian member and does not represent 18 m of freshly deposited marine bedrock.

Bed 3: subrounded-pebble deposit, maximum about 3.5 m
The uppermost of the three waterlain units consists of subrounded pebbles. It lies below the angular head and above the mixed gravel-and-sand unit. Its separate position and clast character are retained, without assigning a more precise age or a fossil assemblage which the published log does not supply.

Bed 2: mixed rounded gravels with sand layers, maximum about 3.0 m
This middle waterlain unit contains a mixture of well-rounded and subrounded pebbles together with layers of sand. It differs from both the overlying subrounded-pebble unit and the lower sandy-matrix gravel. Dalzell and Durrance interpreted Beds 1–3 collectively as a mixture of fluvial and marine material; the summary log does not justify assigning each bed uniquely to a river or beach.

Bed 1: well-rounded pebbles in a sandy matrix, maximum about 3.5 m
The basal unit of the numbered sequence contains well-rounded pebbles set in sandy material. It rests above the Devonian rock platform and underlies the mixed gravel-and-sand unit. The rounding indicates transport and reworking, but does not by itself prove a particular interglacial age.

Underlying rock platform: about 7 m OD
The Pleistocene section rests on a rock platform at approximately 7 m above Ordnance Datum. This is an elevation, not a sediment thickness or a measure above the tide on the day of a visit. Later Quaternary synthesis continues to recognise Lee Bay’s raised-beach deposits on this platform. The suggested Ipswichian age in the river-capture interpretation remains an inferred correlation, not a directly measured numerical date from this section.

Separate survey description of the cliff at SS 6937 4921

The 1985 survey memoir records the same general head-over-gravel relationship using a two-package description at a specified exposure. Its estimates differ from the maximum values in the numbered four-bed account, and should not be spliced into that log or counted as additional layers.

Survey head package: approximately 20 m
Large angular blocks of local Devonian sandstone occur in a brown, silty loam matrix above the gravel. The blocks were described as randomly orientated. The approximately 20 m estimate belongs to this survey exposure; it does not replace the approximately 18 m maximum given in the separate four-bed description.

Survey gravel package: perhaps 4 m
The lower package contains small rounded pebbles of Devonian sandstone, slate and quartz, with a small quantity of flint. Its yellowish-brown sandy loam and sand matrix is locally cemented into sandrock, and parts show rough stratification. Vegetation and modern beach deposits obscured the lowest exposure; seepage near high-water mark was only a possible indication of the base. The survey’s tentative thickness is therefore not a securely complete measurement of all the lower waterlain units.

Gravel origin and correlation
The survey memoir favoured a glaciofluvial origin for the gravel and considered the absence of shells an objection to interpreting it as a raised beach. Dalzell and Durrance instead recognised mixed marine and river material, an interpretation retained in the later conservation review; a 2024 synthesis also includes Lee Bay among the raised-beach localities. These are differing interpretations of the lower deposits. Sparse flint does not establish an exposed Chalk bed here: the survey discussed derivation from material already on the surrounding higher ground, with a vanished Cretaceous cover a less favoured alternative.

Buried fill in the Lee Abbey gap
The neighbouring dry gap at Lee Abbey contains substantial Pleistocene slope deposits. Dalzell and Durrance’s published abstract reports a geophysically estimated 31 m of cover and a bedrock floor at about 78 m OD. These figures describe the buried valley at Lee Abbey, not the cliff log at the head of Lee Bay. The ground surface, the buried rock floor and the raised platform on the shore must remain distinct when interpreting the landscape.

Drainage evolution and remaining uncertainty
One influential reconstruction makes the Lee stream a former eastward-flowing tributary of the East Lyn through the Lee Abbey gap. Coastal erosion first captured the main river near Lynmouth, then cut back into the tributary to create the present Lee Bay outlet. This revised older proposals that the main East Lyn itself flowed directly through the Lee Abbey gap. An alternative ice-marginal drainage explanation has also been proposed for the wider dry-valley system; the conservation review did not consider it conclusively disproved. Much of the head accumulation is interpreted as cold-climate, probably Devensian, slope movement after the older valley routes had ceased to carry their former rivers.

References

Edmonds, E. A., Whittaker, A. & Williams, B. J. (1985). Geology of the country around Ilfracombe and Barnstaple. Memoir of the British Geological Survey, Sheets 277 and 293.
British Geological Survey. Lexicon of Named Rock Units: Lynton Formation (LNSL), checked 10 October 2026.
Campbell, S. (1998). The Valley of Rocks. In Campbell, S., Scourse, J. D., Hunt, C. O., Keen, D. H. & Stephens, N., Quaternary of South-West England. Geological Conservation Review Series 14, pp. 234–238.
Dalzell, D. & Durrance, E. M. (1980). The evolution of the Valley of Rocks, North Devon. Transactions of the Institute of British Geographers, new series 5(1), 66–79. Abstract preserved by Exmoor National Park Historic Environment Record, SEM8447.
Phillips, J. (1841). Figures and descriptions of the Palaeozoic fossils of Cornwall, Devon and West Somerset, pp. 183–184.
De la Beche, H. T. (1839). Report on the geology of Cornwall, Devon and West Somerset, pp. 47–48.
Arber, E. A. N. (1911). The coast scenery of North Devon. London: J. M. Dent & Sons, pp. 45–46, 177 and 236–237.
Somerset Environmental Records Centre & Somerset Geology Group (2021). Review of Somerset’s Local Geological Sites 2017–2021: Final report for the Exmoor area, May 2021, Appendix 1, p. 17.
Bennett, J. A., Cullingford, R. A., Gibbard, P. L., Hughes, P. D. & Murton, J. B. (2024). The Quaternary geology of Devon. Proceedings of the Ussher Society 15, 84–130.
Pound, C. J. (1995). The sedimentary evolution of the Exmoor Basin during the late Emsian–early Eifelian: the Lynton Formation. PhD thesis, University of Plymouth, especially Text-figure 5.1, p. 306.