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THE SUFFOLK GEOCOAST – BAWDSEY EAST LANE TO THE MANOR ROGER DIXON This paper describes the coastal walk from the Martello Tower at East Lane, Bawdsey along the beach to Bawdsey Manor and Quay. The total distance on foot is about 2 ½ miles and should take about an hour if no stops are made. The walk is ‘easy’ – along level sand for most of the way, although walking on shingle is necessary at the southern end of the walk. However, the walk is tide-dependent, particularly at the northern end of the walk. Time your walk to coincide with low tide and to within two hours either side of it. • Do follow the Suffolk Naturalists’ Society field excursion guidelines. • Parts of the coastline are rapidly eroding and cliff falls occur at frequent intervals. The cliff is therefore unstable – do not go near the cliff, top or bottom, where there are overhangs. • The London Clay surface is extremely slippery – tread with great care. • Stout footwear is essential; dress appropriately for the weather; take plenty of water. East Lane Parking is available in a small car park adjacent to an abandoned WW2 gun site and defences [National Grid Reference TM358400], but the walk starts at the Martello Tower [TM356398]. For convenience at the end of the walk, a second car may be left at Bawdsey Quay [TM332378] or the nearby larger picnic site car park. Coastal Defences The recent history of the Martello Tower has been well documented in the local press. Built in 1809 with 750,000 bricks at a cost of £9,500, it helped protect the shore from Napoleon’s forces. In summary, prior to the 1990s it was protected by over 20 m of shingle beach and 25 m of land, and wooden groynes restricted long-shore drift. It was restored and converted into a holiday home. In 1997 a big storm removed all the beach and some of the cliff. By 2005 the tower stood only 10 m from the cliff top. Following the storm, Suffolk Coastal District Council approved emergency funding for limited boulder-style defence work in front of the tower. However, East Lane Point is considered of key strategic importance in controlling the movement of shingle between Aldeburgh and Felixstowe and the work exacerbated erosion immediately to the south. Bawdsey scored low on DoE and Environment Agency priority lists for coastal defences. Consequently, the East Lane Trust was formed to raise privately the funds needed for sea defence work to give even greater protection to farm land, homes and the tower. Locally owned farmland in Hollesley, Bawdsey and Alderton was donated to the Trust, which then sold it off for housing development. In 2008, having gained formal consents allowing residential development on plots that lay outside the ‘Local Plan’, this privately funded project was given the final go-ahead. It is believed to be unique in England, and work began in September.
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According to the press 22,000 tonnes of ‘granite’ were brought by barge from Norway, each boulder weighing c. 6 tonnes, to make ‘rock armour’ for c. 350 m of cliff. In fact, much of the material is igneous Larvikite and Gabbro. There is also a large proportion of Carboniferous Limestone, complete with fossil crinoids, corals and brachiopods, from northern France. Work was completed in June 2009 at a cost of c. £2·4 million. Although some of the excellent exposure of London Clay and Red Crag near the tower had been lost as a result of the work and subsequent slope degradation, the focus of erosion had merely shifted slightly, for within 2 months of completion waves still reached the base of the cliffs and falls were still taking place. Now, although the ‘rock armour’ has by all accounts performed as intended, the entire shingle beach for over 600 m south of the tower has been removed by storms, the cliff is actively being rapidly eroded, and the section has never looked better! (see Plate 23). The London Clay There is a rough trodden path down the talus slope by the end of the ‘rock armour’, just south of the Martello tower. The London Clay comprises brown and grey predominantly silty clays that were deposited in a shallow sea, up to 100 m deep, that covered much of south-east England during the Eocene Period about 53 million years ago. England had a warm subtropical climate, with luxuriant rain forest and coastal mangrove swamps. Large sluggish rivers carried sediment and plant debris out to sea, where it settled and compacted on the sea floor. Plant debris, logs and branches, seeds and fruits, are now preserved as pyritised fossil wood. Waltonon-the-Naze (see Daley, 1999), only 16 km away, is a key locality for the study of Palaeogene plants in Britain. The London Clay exposed at Bawdsey is very similar to that exposed on the foreshore at Walton. Many species of sharks and other fish swam in the seas, and other vertebrates, including turtles, have been found. Walton is also an internationally important site for finds of tiny bird bones – also found at Bawdsey. A small invertebrate (mostly mollusc) fauna has been recorded. Currently about 5 m of blue-grey silty London Clay (Harwich Formation) is well exposed in the cliff and on the foreshore at East Lane. When viewing the wave-cut platform from the beach or cliff top, the bedding can be picked out quite clearly, showing that the London Clay has been gently folded with some small faults. Much pyritized debris can be found washed out on the beach; there are also pockets of drifted woody material which contain fruits, diatoms and radiolaria. The foraminifera Astrorhiza is abundant. The teeth of the sharks Carcharias hopei, C. teretidens, Striatolamia macrota and Otodus obliquus, and fish vertebrae can be found. The thin layers of pale creamy yellowish rust coloured sediment, layers of volcanic ash seen in London Clay sections in the Orwell (eg. at Nacton Shore) and Stour (eg. Stutton Shore) Estuaries, do not seem to be present here, suggesting that the Bawdsey horizon is at the top of the Harwich Formation. Originating from ocean floor volcanoes as the North Atlantic opened up with
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the break-up of Greenland-Rockall plate, the ash was wind-blown into the North Sea area. The ash deposits can be correlated over the North Sea Basin and similar bands are found in Denmark & NW Germany. Over 30 layers are recognised in Suffolk and northern Essex and date to about 53 million years. Calcareous mudstone concretions, ‘septaria’, once used locally for making ‘Roman’ cement can be found in thin bands within the London Clay. The Red Crag The London Clay/Red Crag unconformity can be seen in the cliff. It is highly irregular, partly due to cryoturbation during the Anglian Glaciation, but in many ways resembles the scoured, eroded, undulating London Clay surface of the present wave-cut platform. The Red Crag is now assigned a late Pliocene age, around 2·8–2·4 million years old. It was formed in a high energy, shallowing sea dominated by strong tidal currents, with submarine sand-waves piling up against the shoreline to the west. There is c. 2·5 m of Glycimeris-rich Crag at East Lane, with a well-developed basal pebble bed of phosphatic nodules, which are still loosely referred to as ‘coprolite’ (wrongly, for very few are true coprolites!) (see Plate 24). Excavation of this phosphatic material led to the development of Suffolk’s C19th ‘coprolite’ industry. The pebble bed contains Boxstones, rounded cobbles of a local Miocene sandstone, some containing casts of fossils when broken open (see Plate 25). Large flints and material derived from the London Clay are also common. It has yielded its own vertebrate fauna, including Cetacean bone fragments, teeth of the shark Isurus hastalis and, during a recent field excursion, the rare tooth of a Red Crag rhino (Dicerorhinus megarhinus). As you walk, look for the evidence of rapid erosion: the wave-cut platform swept bare by currents, trees and concrete war defences fallen onto the beach from the cliff top, and lengths of plastic land drain dangling from the cliff face. Particularly spectacular are the rotational landslips which periodically occur, exacerbated by the combination of water seepage from the base of the Crag at the London Clay boundary and rapid removal of debris from the base of the cliff. At high tide, waves lap at and undercut the base of the cliff. The Mid-point The character of the coast changes in the mid-section of the walk, from erosional to depositional, with the development largely between 1938–1945 of a more permanent broad shingle platform, a narrow foreland, edged by a large storm ridge and formed above the foreshore. Up to ten small (<1 m high) storm ridges can be observed between normal high water mark and the foreland. The shingle is colonised by Sea Kale (Crambe maritima) and Yellow Horned Poppy (Glaucium flavum). Sea Buckthorn (Hippophae rhamnoides) starts to make an appearance, but is more common around the Manor. At low tide, well developed beach cusps can also be observed on the foreshore. Cobbles of gabbro and limestone from East Lane can commonly be found all along the beach as far as Bawdsey Bar.
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Bawdsey Manor The Southern Cliff Sixty years ago the cliff north-east of the Manor, a SSSI, was considered to be the finest Red Crag exposure in East Anglia, a view still held by Spencer in 1971, when over 2 km of the section was well exposed. The junction between the Red Crag and London Clay was clearly visible. However, the persistence of the shingle beach and storm ridge means that erosion and cliff falls no longer keep the section fresh (compare with East Lane!). The cliff face is now much obscured by 50 years of talus accumulation and the exposure relatively poor. However, the Red Crag and London Clay are still to be seen in some places. London Clay Well records show the London Clay at Bawdsey Manor to be 87 feet (26·5 m) thick (Whitaker 1906). A large quantity of pyritised wood can be found on the foreshore. The Red Crag The basal Red Crag pebble bed is poorly developed here, but some phosphatic nodules and pebbles of London Clay can be found in some of the basal Crag layers, and borings by Red Crag piddocks (Zirfaea crispata) into the former London Clay surface have been recorded. At the northern end of the section, the basal layers contain laminated and rippled silts interbedded with thicker layers of medium sand. These are overlain by medium and large scale sand-waves with trough- and channelbedded horizons, laminated rippled silts and mud drapes. Small trace fossil burrows occur at some horizons. At the southern end of the section, what appears to be one single 4 m high false-bedded set rests directly upon the London Clay. However, in the mid1970s a clearly defined reactivation surface was visible, with trace fossils extending down from it, indicating that this is two stacked sand-waves rather than one. The section thus shows that there is a sequence of sand-waves, with bottomsets and foresets represented by the different lithologies (see Plate 26). The dominant current direction indicated by the sand-waves is WSW (240o–265o), with current velocities of approximately 0·6 m/sec, with a water depth of around 10–15 m. However, a significant number of structures show current directions to the NNE. While some of this difference is due to vortex and eddy movements in the lee of a migrating sand-wave, some is the result of tidal flow patterns and is characteristic of much of the upper part of the Red Crag between the Deben and Butley Rivers. The mollusc fauna is dominated by Spisula-Mytilus-Mya assemblages (Spisula ovalis frequencies up to 32%, Mytilus edulis 19·9%, Mya arenaria 16·5%), again characteristic of the Red Crag in this area [compare with Walton, where the dominant fauna contains <5% intertidal and infralittoral species, <5% Spisula, but up to 25% Glycimeris]. The high frequency of intertidal and infralittoral species, such as Mya and Mytilus suggest a nearshore, shallow water environment. The Mytilus may have lived as shell
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gravel epifauna on the ripple crests, to be swept up by currents and incorporated into the foresets. The greatest species diversity is found in the larger sand-waves at the southern end of the section – about twice as many species as the smaller sand-waves to the north. It is evident that transportation, sorting, reworking and comminution of the shells were important processes. But in general the fossil assemblages do reflect the communities that lived in the vicinity at the time. Pulhamite The final part of the walk is at the southern part of the cliff, adjacent to the Manor. It is of interest because of the excellent exposure of Pulhamite – a fabricated ‘rock’ of cement, crag and modern beach shingle containing many oyster and whelk shells. Pulhamite was named after James Pulham, a local Woodbridge builder/contractor and artistic specialist plasterer, at first referring to a plaster-like material based on ‘Roman cement’ used for decorative mouldings. Several can be seen on shop and house fronts in Woodbridge. His son, also named James, continued with the business but developed a landscaping business using the artificial stone, and executed much of the later Victorian work, including the Boating Lake in Battersea Park, at Audley End, Brayfordbury House (Berks), Waddesden Manor (Bucks), St James’ Park, and elsewhere in the south east. The finished effect looks very realistic and has confused many a geologist (see Plate 27)! The Bawdsey artificial cliff was made in about 1896 by Pulham II, only two years before his death, and his son. It is possible that Pulham IV was also involved. Lady Quilter, a keen gardener (Percy Thrower’s father worked here), had laid out a four hundred metre cliff walk as an alpine rockery, with meandering paths, tunnels and grottos, covering and stabilising the cliff face. A photograph of 1882 shows this part of the cliff was previously an excellent Crag exposure – so much so that Boswell (1928) and Whitaker (1885) both make special comment on the abundance, variety and good preservation of the shells. Erosion, weathering and a little vandalism have exposed ‘windows’ through which the internal structure of the artificial cliff can be seen. The basic shape of the structure was created using blocks, bricks and rubble, which was then overlain with Pulhamite cement. It has a realistic gritty sandstone texture, but does vary in its composition and final effect, and resembles bedded rocky crags with bedding planes and joints. It has proved remarkably durable; Pulham claimed that this was due to care in the mixing of the ingredients and care taken in the pouring and sculpting of the material. The Manor Estate has, over the last few years, cleared much of the overgrown vegetation and restored much of the Pulhamite garden – it now looks superb and is well worth a visit when the garden is open to the public (see Plate 28). The Bawdsey Bar This shingle spit is the Deben’s version of Orford Ness – a spit formed where sediment brought by long-shore drift from the north has accumulated across the mouth of the river.
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Although it is possible to cross over to the bar at low water spring tide, it is not recommended; if you do, pay very close attention to the state of the tide. Boxstones and pieces of fossil bone, usually from whales, derived from the Red Crag cliffs may be found. The ancient port of Goseford, at the mouth of the river, was ‘lost’ in the 15th Century because of the strong tidal currents, constantly shifting shingle banks, and lack of navigable channel at low tide, all making navigation into the estuary notoriously difficult. To complete the walk, follow the footpath by the perimeter fencing to the Manor Estate to the small car park at Bawdsey Quay. If you have not left a car here, walk along the B1083 to Bawdsey village; turn right down School Lane, following it to the end, where it joins East Lane; turn right again and follow the lane to the car park. Endpiece The Suffolk GeoCoast project was launched by GeoSuffolk in 2005 to promote the geology within the Suffolk Coast and Heaths AONB. To date a series of field excursions and leaflets have resulted. This is the first of a series of guided walks and drives, with the ultimate aim of producing a printed geological guide to the coast. Further details about the geology of the East Lane section can be found in Dixon (2011) and the Bawdsey Manor section, including statistical details of the molluscs, in Dixon (2005). References Boswell, P. G. H. (1928). The Geology of the country around Woodbridge, Felixstowe and Orford. Memoir of the Geological Survey of Great Britain. HMSO, London. Daley, B. (1999). London Basin: eastern localities. In: Daley, B. & Balson, P. British Tertiary Stratigraphy. Geological Conservation Review Series No. 15, Joint Nature Conservation Committee, Peterborough. pp 23–72. Dixon, R. G. (2005). Field Meeting: Coastal Suffolk Crag Week-end. Proceedings of the Geologists’ Association. 116: 149–160. Dixon, R. G. (2011). Field Meeting: A Day on the Bawdsey Peninsula, 22nd May, 2010. Proceedings of the Geologists’ Association. 122: 514–523. Spencer, H. E. P. (1971). A contribution to the geological history of Suffolk: V. Transactions of the Suffolk Naturalists’ Society. 15: 279–357. Whitaker, W. (1885). Geology of the country around Ipswich, Hadleigh and Felixstowe. Memoir of the Geological Survey, England and Wales. HMSO, London. Whitaker, W. (1906). The Water Supply of Suffolk, from Underground Sources. Memoir of the Geological Survey of Great Britain. HMSO, London. Roger Dixon The White House 7 Chapel Street Woodbridge Suffolk IP12 4NF.
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Plate 23: General view of the East Lane cliff section. The end of the ‘rock armour’ is on the left. Note the beautifully exposed London Clay wave-cut platform, with only a thin veneer of sand derived from the cliff. (p. 99).
Plate 24: Red Crag basal pebble bed containing abundant phosphatic nodules (seen here as black pebbles); the large shells are Glycimeris (Dog Cockles), many in a convex-up, hydrodynamically stable position. The Crag rests on London Clay. The photo was taken during construction of the sea defences – hence the large boulders on the right. (p. 100).
R. Dixon R. Dixon
Plate 25: A Boxstone from the basal Red Crag, containing the cast of Glycimeris. (p. 100).
Plate 26: Large-scale, characteristically Red Crag sand-waves can be seen in the cliff near Bawdsey Manor. (p. 101).
R. Dixon R. Dixon
Plate 27: Part of the Pulhamite cliff garden adjacent to the Manor. Note how it resembles a natural rocky outcrop. (p. 102).
Plate 28: A detail of a path through the Pulhamite garden, with a â&#x20AC;&#x2DC;caveâ&#x20AC;&#x2122; on the left, taken shortly after restoration. (p. 102).