INTRODUCTION:

Related Webpages, East and West.

Go East:
Lyme Regis, Westward to Haven Cliff, near Axmouth

Go West:
Sidmouth, Devon

INTRODUCTION:

General Objectives of the Webpage

This webpage, like others in the series, is intended to provide photographs, diagrams and text information to enable anyone with some basic geological knowledge to understand the area under discussion. It is also intended to direct the reader to specialist work and thus it is referenced throughout to scientific literature.

Although the Beer cliffs have been examined and photographed from time to time by the present author over the last half century, the study of this area is largely dependent on previously published work. The classic work on the Cretaceous strata is to be found in the papers of William E. Smith (1961 etc). These papers are fundamental to the area, but modified and more detailed information has later become available. The older terminology of Smith, although quite well-established in the literature, has been replaced by a new nomenclature of Jarvis and Woodroof (1984). These authors provide a greater level of detail, with a series of good vertical sections, and much useful discussion of hardgrounds. Other papers relevant to the area and the strata here are also referred to.

INTRODUCTION

General - Beer Village and Beach

Dramatic scenery is provided by the vertical cliffs at and around the old fishing village of Beer. These white cliffs of Chalk contrasts with the blue of the clear seawater. They are part of the westernmost stretch of Chalk cliffs on the English Channel coast. At Seaton, east of Beer, there is, in striking contrast, the red Mercia Mudstone of Triassic desert origin. These red mudstones also occur to the west of Beer at Branscombe. Here they crop out beneath the Cretaceous Chalk. Further west, near Sidmouth, Triassic red-beds occupy most of the cliff.

The Chalk in the Beer area is unusual. Strange facies, such as the Cenomanian Limestones and the Beer Stone occur in a area that was subject to penecontemporaneous movement. Remarkable lateral facies changes and unconformities here have been studied in detail in classic work by Smith (1957a; 1957b; 1961; 1962) and briefly explained by the same author in Ager and Smith (1965;1973).

INTRODUCTION

Safety and Risk Assessment

Some specific hazards with regard to Beer and Seaton are mentioned here. There can be problems with the tide on both sides of Beer Beach. It is only possible to walk from Seaton to Beer or vice versa at low tide, and a small scramble over rocks may be involved. There is some chance of being cut off but generally if the the tide is too high you may be able walk back to Seaton. Southwest of Beer Beach the problem could be more serious. It is certainly possible to be cut off by the tide if progressing along the foot of the Chalk cliffs. Trying to climb the Chalk cliffs is dangerous and should not be attempted. Take care when next to vertical or steep Chalk cliffs because there is risk of rock-fall. Safety helmets may be worn as a precaution. Any particular place where there are signs of recent rock falls should be avoided. Never hammer flint or chert because dangerous splinters can fly off and your eyesight may be at risk. Take care with slippery rocks at low tide. The usual caution is needed on high cliff tops and the edge should not be approached. This webpage is not an itinerary; it does not give advice to go to any specific place and take part in any specific activity; it is just a description of the coast in this region. Any activity is undertaken at your own risk.

INTRODUCTION:

Topographic Maps

INTRODUCTION:

Geological Maps

INTRODUCTION:

Aerial Photographs

Notice on this general aerial photograph of the coast around Beer and Seaton, the deflection of the River Axe by the eastward growth of a shingle spit. Note the Hooken Cliff landslide. You can see that Pounds Pool Beach is like a small version of Beer Beach.

A larger scale aerial photograph of Beer Beach shows the large accumulation of rounded flint and chert pebbles. The rock platform of East Ebb at the eastern end of the beach is probably the base of a former headland. When this existed Beer Harbour was probably a more well-defined embayment, almost a cove. A large groyne now prevents major loss of shingle to the east.

INTRODUCTION:

Cliff Sections

PALAEONTOLOGY:

Cretaceous Fossils

Some of the common Cretaceous fossils are illustrated here. The occurrence of some of these in mentioned in the list of stratal units given below. Examples of certain of these fossils may be seen in the cliffs of the Beer region.

STRATIGRAPHY:

Stratal Sequence

To study the Cretaceous strata of Beer it is necessary to have some knowledge of the traditional zonal schemes of the Albian Stage of the Upper Greensand, and the Cenomanian and Turonian Stages of the Chalk . The tables above give the traditional zonal schemes. The newer lithostratigraphic nomenclature of the British Geological Survey is also shown in one of the tables; it must noted, however, that the lithostratigraphic units at Beer are different from those in east Dorset, the Isle of Wight and Sussex. The east Devon Cretaceous has an unusual, marginal or shallow facies in comparison to that of localities elsewhere in southern England. Certain parts, particularly of the Cenomanian are very different.

The "Cenomanian Limestone" of older terminology has been renamed the "Beer Head Limestone" by Jarvis and Woodroof (1984). It has four members from the base upwards: the Pounds Pool Member, the Hooken Member; the Little Beach Member, and the Pinnacles Member. Both terminologies are used here to some extent, but the paper by Jarvis and Woodroof (1984) needs to be read because it provides much more details, particularly in the detailed graphic logs.

STRATIGRAPHY:

Cretaceous Sequence at Beer - Details

A reference list of the strata present in the Beer and Seaton area is given below. This is based on Smith in Ager and Smith (1965; 1973) and is particularly useful for recognising the Cretaceous units.

---

Turonian and Senonian (pars)
(Zones of Holaster (Sternotaxis) planus and Micraster cortestudinarium) ..... 27 metres.
White chalk containing numerous courses of white partially silicified chalk nodules which project from deeply weathered sections such as that in Annis' Knob, the conspicuous bluff by the side of the cliff path between Beer and Seaton. Lines of black nodular and tabular flint also present. Rowe (1903) found Micraster spp. characteristic of both the Holaster planus (Stenotaxis planus) and Micraster cortestudinarium Zones. These show the rock to be Lewes Nodular Chalk from the base of the Upper Chalk.

Turonian,

Upper Part of Middle Chalk
- Terebratulina lata Zone ..... 11 - 48 metres.

Massive white chalk which, unlike the development of this zone in south-east England, contains numerous courses of black nodular flints: two conspicuous flintless marly bands provide excellent marker horizons in the cliffs between Beer and Branscombe.

Lower part of Middle Chalk
- Inoceramus labiatus (Orbirhynchia cuvieri) Zone ..... 0 - 18 metres.

Normally rather hard flintless cream-coloured chalk consisting of layers crowded with small intraclasts (pebbles) of chalk and some nodule-free layers. The lowest bed is usually a hard rough limestone containing irregularly scattered grains of quartz and glauconite, and often displaying honeycomb weathering. Up to four metres of granular limestone composed of finely comminuted shell debris (the Beer Stone) locally developed near the base. The nature of the underlying strata is very variable, and the zone may rest unconformably on various levels of the Cenomanian Limestone, or pass down apparently without a break into the Orbirhynchia Band, or rest on a burrowed erosion-surface at the top of the Orbirhynchia Band with the Neocardioceras Pebble Bed at the base. At the western end of Hooken Cliff, east of Branscombe Mouth, the zone is absent due to overlap by the T. lata chalk.

------ Haven Cliff Hardground -------

Pinnacles Member of the Beer Head Limestone (Orbirhynchia Band, Division C).
Probably top Cenomanian but has been considered as Lower Turonian
..... 0.2 metres.

Very local in distribution, typically a rather soft, white, chalky bioturbated limestone, containing abundant grains of quartz and glauconite, patches of which may be more firmly indurated. The rhynchonellid Orbirhynchia especially O. wiesti and forms transitional to O. cuvieri are abundant. A complex pebble bed may be present at the base in which fossils, particularly ammonites, occur in several modes of preservation, viz. chocolate-brown, abraded or well-preserved, phosphatised casts; green-coated lightly phosphatised fossils and unphosphatised fossils including silicified forms. The fauna include forms indicative of both the Upper Cenomanian and early Turonian and indigenous Lower Turonian forms.

---- Erosion Surface ----

Note: The name "Cenomanian Limestone" is an old name used by Jukes-Brown and Hill (1903). It is been much used in older literature on the cliffs. This peculiar condensed limestone sequence has been re-examined in more detail by Jarvis and Woodroof (1984). They have used the term "Beer Head Limestone" for what was formerly called the "Cenomanian Limestone". Both schemes are used in various parts of this account, and it is easy to translate from one to the other. Jarvis and Woodroof (1984) divide the Beer Head Limestone Formation into the: Pounds Pool Member (A1 at the base), Hooken Member (A2), Little Beach Member (B) and the Pinnacles Member (C).

(Supplementary discussion: There has been, in the past, some argument about Division C, the Pinnacles Member of Jarvis and Woodroof (1984). Jefferies (1963) correlated Division C with Actinocamax plenus Marls (i.e. the well-known Plenus Marls as seen at Lulworth Cove, for example). Jefferies (1963) considered these to be of Upper Turonian age. Thus, Smith (1965) proposed that the association of these sediments with the specifically named Cenomanian Limestone should be discontinued to avoid confusion. He used the term "Orbirhynchia Band" because of the presence of the brachiopod Orbirhynchia wiesti (Quenstedt). In the light of descriptions of equivalent but expanded strata beneath the Beer Stone, the matter has been discussed by Ali et al. (1972). They used the Orbirhynchia Band terminology and provided a detailed section. However, the position of the Plenus Marl with regard to stages is relevant to this discussion. It has at various times been placed in the Turonian or the Cenomanian. The BGS, British Geological Survey, based on recent work by Mortimore (2004) place it in the Cenomanian. If this is correct then Smith's (1965) terminological objection might have been unfounded, anyway. This is largely a historical problem. Terminological difficulties still remain to some extent but it is now the Pinnacles Member of the Beer Head Limestone Formation. In the stratal list of succession for the cliffs given here the Orbirhynchia Band is referred to in some places as a separate small unit above the Cenomanian Limestone. At the Beer Stone quarries it is a major unit. The diagrams given here should make the matter relatively clear.)

Note regarding the correlation diagrams above. The upper of the two correlation diagrams above is based on Hart (1982) in Durrance and Laming (1982). However, Jarvis and Woodroof (1984) show a rather different pattern in their scheme shown immediately above the text. Their terminology is also shown here. Their Pounds Pool Member (A1) is not shown to continue north of the middle of Pounds Pool Beach. The Hooken Member is dominant until East Ebb is reached. At Whitecliff the Little Beach Member is the thickest (of a thin sequence). They take the Pinnacles Member from Beer Head through all localities to Whitecliff.

The Cenomanian (Lower Chalk) is very peculiar at Beer, and quite different from that at most localities in southern England. It is locally reduced to a thin, cream-coloured bed, with glauconite grains. This bed is less than a metre thick at the harbour or beach of Beer. The reduction in thickness is the result of a local penecontemporaneous high or line of uplift, trending SSW through Beer village and Beer Head (see diagram and map above). It is not often in southern England that much evidence of tectonic movement during the Cenomanian is seen, so this is a feature of special importance.

Divisions of the Cenomanian Limestone or Beer Head Limestone Formation

Little Beach Member (Bed B).

This is Lower and Middle Cenomanian (in part) and is . 0 - 6 metres in thickness. It is a hard white or greyish massive limestone containing grains of quartz and glauconite, either more or less uniformIy scattered throughout the bed, or concentrated in horizontal, inclined and bifurcating streaks or as patches filling the interstices between blocks of limestone. These localised concentrations of calcareous greensand become increasingly frequent towards the top of the bed and many of them appear to consist of sediment carried down from the Orbirhynchia Band (Pinnacles Member) into complex burrow systems. Up to 0.3 m of green and brown stained pebbles occur at the top which is locally a hard brown phosphatic crust in which pebbles and fossils belonging to the Orbirhynchia Band (Pinnacles Member) may be firmIy embedded.

----- Erosion Surface -----

Pounds Pool and Hooken Members = (Divisions or Beds A1 and A2) .

These members are of Lower Cenomanian age and total .0 - 5.5 metres in thickness. The newer names "Pounds Pool" and "Hooken" Members are those of Jarvis and Woodroof (1984). Originally two subdivisions were recognised by Smith (1961 etc) : the younger, the Hooken Member (or A2) is a hard white or greyish nodular limestone containing calcareous lithoclasts and numerous bioclasts which are frequently silicified; quartz grains are comparatively abundant but there is no conspicuous glauconite. The top is usually an irregular, brownish, phosphatised,locally burrowed, erosion-surface, firmIy welded to the base of the Little Beach Member (Division B). Pebbles of limestone, many of which are phosphatised, are often associated with the erosion-surface.
The Hooken Member (A2) is much more widespread than the older subdivision, the Pounds Pool Member, (A1) and frequently rests directly on the Upper Greensand, as at the west side of Beer Beach (see photographs above). The Pounds Pool Member differs from the Hooken Member in containing more frequent and coarser grains and even small pebbles of quartz. A special feature at the base is the occurrence of abundant, very large, coral-like bryozoa (Ceriopora ramulosa).

----- Erosion Surface ----

Middle and Upper Albian ..... up to 12 metres.

Dark bluish grey loams and silty clays, rarely exposed except at Culverhole, Black Ven and Stonebarrow.

----- Major Unconformity ----

---

Towards the west the Cretaceous deposits overstep Lias, Penarth Group (Rhaetic), the Tea Green Marls and the red Mercia Mudstone of the Trias.

---

LOCATION:

Beer Harbour Beach - East

The main cliff which forms the northern side of Beer Harbour, provides the best section in Devon of the Turonian Middle Chalk, as was noted by Woodward, Ussher and Jukes-Browne (1911) . The upper part belongs to the zone of Terebratulina lata, and was given as about 27 metres (about 90 feet) by these authors. The lower part down to the shingle beach (with the red sign fixed to it in the photograph above), belongs to the zone of Inoceramus labiatus (now Mytiloides labiatus; and note that this was the Rhynchonella cuvieri Zone in old literature) and is about 12 to 15 metres (about 40 to 50 feet) thick.

In the labiatus zone, which extends to the natural archway further east, is the representative of the Beer Stone, consisting of two layers of somewhat nodular chalk about 1.5 metres feet thick. Reefs of the Cenomanian Limestone or Beer Head Limestone (Lower Chalk) occur beneath, resting on a floor of Albian, Upper Greensand.

LOCATION:

Annis' Knob, Beer

This location is a conspicuous upper cliff above the eastern part of Beer Harbour (the main Beer Beach). This is situated almost on the axis of the post-Cretaceous Beer Syncline (not to be confused with the penecontemporaneous Beer Anticlinal Axis). As a result of the structure the Chalk here is exposed as high as the Micraster cortestudinarium Zone of the Coniacian Stage.

This location is best described by Rowe (1903), although the terminology is, of course, the older version. Some notes from his classic and substantial work are provided here for the benefit of the general reader:

"Annis'Knob is the name given to the finely weathered bluff above the green slope. The cliff path from Beer to Seaton passes along its foot. This bluff is interesting in that it is practically the only accessible coast section in this zone, save at Pinhay Cliff. The eye is at once attracted by the stong nodular flint-line, which intersects the bluff rather more than half way up. At the base of the bluff is another strong nodular flint-line, with a weaker one one and half feet below it. The upper strong flint-line and the lower and weaker pair can be traced at Pinhay Cliff and Beer Head, though the lower pair are not shown in the former section. At Pinhay Cliff we have alluded to the fact that the upper and stronger flint-line may be taken as a rough guide for separating the zones of Holaster planus and Micraster cor-testudinarium, the actual zoological division occurs at the level of a thin tabular flint band which is 13 ft [4 metres] above it [note re "zoological" that although Rowe is famous for his detailed stratigraphical work, his real objectives were those of zoology or palaeontology and connected with evolution of echinoids]. At Annis' Knob no trace of this tabular flint-band can be seen, but an ordinary flint nodular flint-line occurs at much the same level. This is worth noting, as at Beer Head, the thin-tabular flint band is clearly seen. It is only another example of lithological features being inconstant even within a narrow area. We have alluded to the same thing in the Kent and Sussex paper on pp. 332, 336 et alt.

The air-weathering of the bluff is remarkable. We trace an abundant and characteristic fauna up to the level of the strong flint-line, half-way up the bluff, and are of the opinion that here, as at Pinhay Cliff, the Holaster planus fauna is carried above it, for we find Holaster planus and Micraster praecursor of the group form characterised by "sutured" and "gently inflated" ambulacra, together with an occasional example of Terebratulina gracilis [is this T. lata?]. Thus the boundary line between the zones of Holaster planus and Micraster cor-testudinarium should be purely zoological [i.e. evolutionary] is nothing new, for we note the same thing at Beachy Head (Kent and Sussex, p. 326). In Dorset on the other hand, the naked-eye appearance of the two beds is so different that there is no difficulty at separating them at a glance, and it is of interest to note that that there the lithological and zoological [i.e. palaeontological or zonal] coincides.

[continues]

LOCATION:

East Ebb, Beer Northeast to Whitecliff (and Seaton Hole)

(Note, although not indicated on the photograph above, there may be some Sternotaxus planus Zone Chalk at the very top of the cliff. In old terminology this is, of course, Holaster planus Zone. This zone is Turonian, but within the lithological unit of the Upper Chalk. Elsewhere it is the lower part of the Lewes Nodular Chalk Formation in modern terminology)

Whitecliff is the Chalk cliff between Beer Beach and Seaton Hole to the east. The foot of it can be passed only at low Spring tides, although some of it can be probably be reached at most other low tides. There are accessible exposures at the foot of the cliff showing Upper Greensand and the Cenomanian Limestone or Beer Head Limestone in places. The higher part of the cliff is M. labiatus Zone (Connett's Hole Member) and T. lata Zone (Beer Roads Member and above). A photograph above shows a rotated landslide block of Upper Greensand with chert and Cenomanian Limestone or Beer Head Limestone above. The individual members of the Beer Head Limestone have not been identified on this photograph, but Jarvis and Woodroof considered that only the Hooken Member (thin), the Little Beach Member and the Pinnacles Member are present here. They recognised four hardgrounds at Whitecliff (or White Cliff). A major factor is that the Pounds Pool Member (which is thick at Hooken Cliff) is not present. Thus the Beer (penecontemporaneous) Axis is not symmetrical but could be considered in broader terms as a general thinning towards the fault at Seaton Hole.

LOCATION:

Beer Harbour Beach - West Side and West Ebb
(the cliffs from western end of the main Beer shingle beach, including Small Point and the northern end of West Ebb, and then southward to Pound's Pool Beach)

The Chalk cliffs, with some Upper Greensand at the base, on the west side of the main beach at Beer are of great interest. Part is accessible at almost any tide conditions. The ledges, though, extending south to The Hall, a place of caves, are only accessible at low tide. Note that if you continue beyond The Hall to Pound's Pool Beach you need to take great care with the tide or you may be cut off when it rises. The diagram shown here, based on Perkins (1971), should give a good idea of the general structure and succession in the western cliffs. The details at the base of the cliff, where there is contact between Upper Greensand and basal Chalk is quite complex though.

LOCATION:

The Hall (cave) and Pounds Pool Beach (beyond)

Pounds Pool Beach is an interesting separate beach from Beer Beach. It lies to the south and is reached at low tide through a cave known as The Hall (take care not to be cut off by the rising tide). It provides a good section from the Beer Head Limestone or Cenomanian Limestone up into Beer Roads Member of the Seaton Chalk Formation (Mytiloides labiatus Zone Chalk, Middle Chalk). The development of the cave is an early stage in the formation of a Chalk stack. It will break through eventually.

LOCATION:

Beer Head

Beer Head provides an excellent high and vertical cliff section of Chalk above Upper Greensand. Because this is west of the axis of the roughly N-S Beer Syncline, there is more Upper Greensand visible here. This glauconitic sandstone dips towards the east and the junction with the Cenomanian Limestone or Beer Head Limestone is relatively high in the cliff. Rowe (1903) was very impressed by this cliff section. It can be reached by the Hooken Cliff footpath or by traversing along the beach from Branscombe Mouth.

LOCATION:

Hooken Cliff, Landslip and Major Chalk Section

Walk from Beer along the cliff top south to Beer Head, and the Hooken Cliff Landslip will soon be encounted west of Beer Head. There is a fairly easy path down through the undercliff which descends about 100 metres in terms of vertical height. It is mostly narrow and has steps in places. A side path branches off to the old Beer Stone Adit, but the short and steep climb to this is not entirely safe, in spite of the possible presence of a rope or ropes. There are short cuts off from the main path to the beach once the Pinnacles have been passed (it is not safe to divert before this), but they vary in steepness from difficult to easy. If in doubt just continue down on the main path and you will reach the beach in due course.

An alternative to descending the Hooken Cliff Landslide is to proceed by car to Branscombe Mouth. You can park your car there, and walk eastward along the beach to the foot of the landslide and the base of the Pinnacles. The shingle beach continues eastward to Little Beach near Beer Head. From there the sea comes up to the cliff and there is no continuous route along the shore to Beer Harbour.

At Hooken Cliff there is an impressive landslide. Chalk and Upper Greensand has slipped southward over Triassic mudstones and gypsum.

Presumably based on earlier literature, Perkins (1971) gave a brief explanation of its history:

"The Hooken Landslip is one of several in East Devon but it is not the largest. Dowlands and Bindon lie farther east and Lyme Regis knows the problem of these great earthslides well. The movements have usually been quite sudden, their cause the difference between porous chalk and Greensand beds in the cliff tops and the more clay-like Keuper marls [Mercia Mudstone], Rhaetic [Penarth Group] and Blue Lias beds below. Underground drainage descends easily until it reaches the top of the marls. There it is forced to spread sideways, making the mad surface into a gigantic slide. Tilted slightly seawards, the surface allows masses of chalk to slip off the cliffs. The cause is simple but the view of Hooken confirms the results as spectacular!
Before the slip occurred, South Down Common ran level to the edge of a sheer cliff. Halfway down its face a stream emerged. About 1788 the stream somehow became blocked underground and must have spread out over the marls within the hill, lubricating their surface. A year later a great fissure appeared in the cliff top cutting off about ten acres of land. Suddenly, one night in March 1790, the isolated land slipped down 250 feet, pushing up a great ridge in the seabed beyond and extending the shore outwards nearly 200 yards. Crab pots laid 8 to 10 feet below surface the evening before were found 15 feet above water!"

The seaward landslide may have had a basal shear-plane in the sheared gypsum of the Little Weston Mudstone Member of the Sidmouth Mudstone Formation.

LOCATION:

Beach below Hooken Cliff (foot of the Pinnacles etc)

The beach at the foot of the Hooken Cliff landslide can be reached quite easily either by descending the main footpath through the landslide or by walking eastward from Branscombe Mouth. The beach is of subrounded flint pebbles. There is much landslipped and fallen debris in the area of the Pinnacles, but the dip has mostly remained near to horizontal (the local dip here is slightly eastward).

It is obvious that erosion of the toe of the landslide is quite fast. The Sherborne Rocks are relics of material fallen and eroded from the Pinnacles. Dr. Ramues Gallois (personal communication, 2008) has compared old illustrations with the state of the coast at Hooken Cliff now. He has found that there has been much loss of the slumped land by sea erosion south of the Pinnacles.

LOCATION:

Beer Stone

An unusually hard part of the Middle Chalk, the Beer Stone, has been quarried in Hooken Cliff Landslip, at the adit shown above, and much more extensively in inland quarries. It is still worked in that area. The rock is a grey calcarenite, or shell-debris limestone, and is discussed more detail below. In general terms it is a winnowed Chalk calcarenite on a submarine high, and has similarities to those in the Central North Sea Graben Kennedy (1987). As a winnowed Chalk it also resembles to some extent the Tottenhoe Stone (although this has a different, finer-grained, petrographic fabric) and the Melbourn Rock, and to some extent skeletal carbonate sands in France and Denmark Kennedy and Garrison (1975)

The Beer Stone Quarries are located about 1 mile or 1.6 km. west of Beer Village on both sides of the road to Branscombe. There are guided tours to the old underground mines in the stone from a site on one side of the road. The booklet shown above provides a good description and illustrations.

The Beer Stone is a gritty-textured, calcareous freestone of local distribution which occurs in the Inoceramus labiatus Zone near the base of the Middle Chalk (Ager and Smith, 1965). Thus it is above the level of the Cenomanian Limestone, with which it should not be confused. This Beer Stone, a hard limestone is not present at the beach at Beer, where only the equivalent strata consist of Chalk that is not particularly hard (the thin Cenomanian Limestone at the foot is hard). The gritty texture of the Beer Stone is not due to the presence of angular sand grains, but to an abundance of minute shell-fragments, including debris of Inoceramus (which has a conspicuous layer of calcite prisms). The stone is cream-coloured when fresh, becoming grey on exposure. Its crushing strength is similar to that of Portland Stone (Howe, 1910). It is at present (2010) under investigation for electromagnetic geophysical studies, with porosity and permeability first being determined by photography of thin-sections stained by ultra-violet fluorescent dye (research by Dr. Laurence North at Southampton University).

Examined petrographically under the microscope, this is a quite peculiar type of limestone. It is a calcarenite of diverse skeletal debris. This includes bivalve fragments, foraminifera and echinoderm debris. It is cemented by coarsely crystalline calcite. probably with syntaxial overgrowths. It seems to have been a carbonate shoal sand, but one without the extensive micritisation and ooid development that is common in the Dorset Jurassic limestones. The carbonate sand is dominantly debris of a fairly high energy environment, not with not much, if any, carbonate precipitated on the sea floor. The seawater does not seem to have been supersaturated for carbonate as in Jurassic times in this region. The small percentage of micrite nuclei (although some, of course, would be expected as coccoliths) is probably why the cementation is rather coarse-grained and complex. Beer Stone has some glauconite which can give it a greenish tinge. For technical details see the website: BRE: 2000. The British Stone List. It has a porosity of 30.9%, which is high. The bulk density (bulk specific gravity) is 1.86. Compare to Bowers Whit Bed, Portland Stone (Albion Stone Quarries). This has a porosity of 21.5% and a bulk density of 2.13. Thus the Beer Stone is relatively light in weight and with a high porosity.

The Beer Stone in the quarries at Beer is 4 metres (13 feet) thick, overlain by a 0.9 metre thick (3 feet) "roof course" or "cockly bed" of the quarrymen. The stone is described (Scott and Gray, undated) as "crystalline [perhaps this non-technical term means, fairly coarsely crystalline], granular limestone, the upper 8 ft (2.4 metres) thick-bedded, the lower 5 ft (1.5 metres) harder and thinner-bedded; identifiable fossils are scarce, with Inoceramus mytiloides [i.e. the old "Inoceramus labiatus", the zone fossil of the lower part of the Middle Chalk], O. cuvieri, G. semiglobosa, Conulus castanea, Hemiaster minimus, Nautilus, Ptychodus mammilaris, Lamna appendiculata [the last two are fish teeth]. Chalk and yellowish limestone of the Middle Chalk lie above. See Scott and Gray, undated, page 3, for full details.

Beer Stone has been used extensively in Exeter Cathedral and in Winchester Cathedral. It has also been used in Beer Church, Colyton Church, Ottery St. Mary Church and at the house of Cadhay (Scott and Gray, undated).

As already noted above, the section is important in explaining part of the "Cenomanian Limestone". Excavation and study of the strata beneath the Beer Stone was undertaken by Ali et al. (1972). This shed light on the expanded sequence in this area away from the Beer Axis (ridge). The lithological and palaeontological evidence indicates that the deposits up to the top of Bed 2a, of this paper, are the equivalent of Jukes-Brown's (1903) Division C of the "Cenomanian Limestone" of the local area.

BEER STONE

More on Petrography and Heavy Minerals

The following extract on Beer Stone is from Groves (1931), and provides a useful summary of its mineralogical properties.

"Middle Chalk. - From Beer, Dr. Hume records muscovite, biotite, rutile, tourmaline, andalusite and anatase, the first two species being predominant. Among the tourmalines he noted fibrous aggregates recalling the tourmaline in luxullianite. Jukes-Browne states (1903, p. 545) : 'The Beer Stone is not a chalk but a shell-sand, and its residue contains a variety of minerals which have clearly been derived from land consisting of Granite and Palaeozoic rocks such as occur in South Devon and Cornwall.'
G. M. Davies (1919) has recorded from the Beer Stone tourmaline, staurolite, biotite, zircon, rutile and andalusite, together with chromite associated with serpentine. In the mounted Beer Stone residues kindly lent to me by Mr. Davies, zircons are abundant, the majority being of Dartmoor type. They are accompanied by abundant angular tourmaline, andalusite, topaz, anatase, rutile, biotite, muscovite and some pink garnet. The assemblage as a whole is consistent with derivation from West of England sources, chiefly Dartmoor."

HEAVY MINERALS OF BEER STONE

Mystery of the Chromite, Serpentine and Staurolite.

As noted above Davies (1919) found Chromite and Serpentine grains in the Beer Stone. Here is an extract from his report:

"Samples collected by me last year in the underground workings [Beer Stone Quarries] have yielded additional evidence which is of some interest. A sample weighing 157 grammes was treated with dilute hydrochloric acid and yielded 3.1 per cent muddy residue and 0•32 per cent sand. The latter consists chiefly of quartz, up to 21 mm. diameter, the larger grains being well rounded. There is also a fair amount of felspar, mainly orthoclase, and of muscovite and glauconite, as well as a little flint. The sandy material was treated with bromoform, and the heavy residue was found to amount to 0-0.12 per cent of the stone. Coarse red and black grains are conspicuous in it. The former consist of limonitic matter, and the latter were tested in borax beads on the supposition that they might contain manganese. The beads, however, showed the fine green colour, somewhat yellowish in the oxidizing flame, characteristic of chromium. On crushing the black grains and examining them under the microscope the fragments exhibit the deep brown colour in transmitted light and the isotropic character of chromite. In several instances a green serpentine is associated with the chromite. The other heavy minerals present are tourmaline, staurolite, biotite, zircon, rutile, and andalusite, none of which call for special comment. A second sample gave 0.28 per cent sandy residue, but no chromite was seen in it. A thin section of the stone showed as many as seven fairly large quartz grains in an area of about half a square inch. Detrital chromite does not seem to have been recorded in any Cretaceous or older deposits in England. From this fact,as well as from the coarseness of the grains and the patchy nature of the occurrence, we may conclude that the chromite was derived directly from some area of ultra-basic rocks, possibly the Lizard, possibly an area now submerged beneath the English Channel; and the occurrence is of interest as showing that serpentines as well as granites were being eroded in Turonian times."

This occurrence of chromite and serpentine is quite peculiar. Beer is 170km from the serpentinite of the Lizard, which does, indeed, contain chromite. Davies' suggestion of another offshore outcrop was made at a time when the geology of the sea floor of the English Channel was not well-known. However, the modern geological map of the sea floor of the English Channel does not show any serpentine closer to Beer than that. It remains possible that some serpentinite is present in the English Channel but not exposed because it is beneath the extensive Chalk outcrop in the English Channel (i.e. beneath the Turonian, but not projecting now). It would still have to be at a substantial distance to be beneath the offshore Chalk outcrop, and the probability of this is not great.

Another possibility, much less likely, is that the chromite and serpentine grains are of meteorite origin. The high level of the Chalk sea generally resulted in a low clastic input. Thus the Chalk is normally, although not always, very pure calcium carbonate, with some silica, and occasionally some glauconite and phosphate. The Beer Stone is a winnowed deposit and the winnowing has probably concentrated the rare, non-carbonate grains. This could have included debris of meteorites.

Material believed to ejecta from a meteorite impact event has been found at a coastal site in Portugal Monteiro et al.(1988), and it of interest that this is from the Cenomanian-Turonian boundary. Thus it is almost exactly the same age as the Beer Stone. In addition there is a global iridium anomaly at this boundary.

In spite of a little circumstantial evidence for some extra-terrestrial origin of the chromite in the Beer Stone, there is, however, the problem of staurolite in both the Upper Greensand and the Cenomanian Limestone. It attains 4.2% of the transparent heavy minerals in Division A1 of the Cenomanian Limestone at Mitchell's Rocks in the Hooken Cliff Landslide (Smith, 1961. The detrital mineralogy - etc., p. 314). It is also 4% in the top Upper Greensand at Whitecliff and quite high at Beer Beach, West Side. There is not a major source of staurolite in the region, only a small outcrop of staurolite-bearing rocks in the Lizard Complex. Staurolite is not a likely meteoric material but points, with chromite and serpentine to a larger and concealed Lizard type of complex in the English Channel.

LOCATION:

Seaton Hole, Seaton (east of Beer)

At Seaton Hole a fault with a throw of about 60 metres brings up Triassic Mercia Mudstone (formerly known as Keuper Marl) on the east side. It is mud and desert loess from the interior of a "Sahara Desert" of about 250 million year ago. At this time the British region was at a latitude about that of the modern Sahara desert. In the region there are deposits of gypsum in the Mercia Mudstone and pseudomorphs or natural casts of halite crystals have been found.

The red desert mudstone has green (reduced) bands in it. They are displaced by numerous small faults. In places there are also green reduction spots. These, as shown in the photographs above, can be seen at low tide on a wave-cut platform, just east of the fault plane at Seaton Hole. The green spots are believed to be the result of localised reduction of ferric to ferrous iron around small pieces of organic matter.

Note that the desert red bed facies seen now is probably the result of dehydration with burial and temperature of a brown bed facies. Brown goethite and limonite are hydrated ferric oxides; they can changed to hematite which is simply red ferric oxide without any water of crystallisation. Most modern desert surfaces are brown with limonite, not red with hematite, and this was probably the original situation regarding the Triassic deserts.

For more information on the Mercia Mudstone Group in Devon see Hounslow et al. on the Magnetostratigraphy of the Middle and Upper Trias Mercia Mudstone Group, South Devon, UK.

LOCATION:

West of Branscombe Mouth - Sheared and Nodular Gypsum

Secondary gypsum is well-developed in the Little Weston Mudstone Member of the Sidmouth Mudstone Formation (Gallois, 2007), to the west of Branscombe Mouth. It occurs in West Cliff and Berry Cliff. Nodular secondary gypsum is common, much of it very sheared. There are numerous satin spar veins following conjugate fractures. The gypsum has been a plane of weakness, as is commonly the case, but the displacement above has only caused shearing and not intense brecciation (i.e. it is not a cargneule).

Woodward and Ussher (1911) reported that the gypseous marls extend eastward from Hook Ebb Reef to just before Branscombe Mouth where they dip under the beach. The gypsum has been worked commercially in Victorian times at about 200 metres to the east of Littlecombe Shoot.

Gypsum at the surface in strata older than Tertiary is normally secondary gypsum. Primary gypsum is converted to anhydrite under deep burial. Thus gypsum seen in Triassic rocks is a hydration product of anhydrite. Petrographic study is needed to determine whether the initial deposit was primary gypsum or primary anhydrite. The latter is more likely to have originated in the more arid conditions and in the presence of halite. Primary gypsum is more common in semi-arid conditions, particularly where halite is not abundant. The Triassic gypsum of southern England was associated with halite and there are large quantities of this undergound in some areas. At the surface there are just pseudomorphs after halite in places, as at Salcombe Mouth (Woodward and Ussher, 1911).

Thus the Triassic gypsum, west of Branscombe Mouth may well have originated as anhydrite nodules like those present in the Dukhan Sabkha of Qatar. It is also possible, though, that the original nodules were of gypsum, as in the sabkhas of northern Egypt, rather than anhydrite, since both forms of calcium sulphate develop as white nodules and enterolithic veins. These form in the capillary zone of desert sabkhas, within about metre of the saline water table.

SUPPLEMENTARY TOPIC - REGARDING BEER

Organisms from Beer Surviving in Space

Beer is notable as the site from which sea-shore rock have been sent into space. Upper Greensand from the foot of the cliffs, at the southwestern part of the beach, has a coating of green algae and other micro-organisms. The Beer slime has been chosen to orbit the earth in space to see just what can survive. A Beer bacterium can still live after exposure to vacuum and ultraviolet radiation. It came back to Earth still alive! Perhaps, one day, microbes from Beer might colonise some distant planet, like Mars.

For more information on Beer micro-organisms in space see the paper by Professor Charles Cockell and his colleagues from the Open University. It is:

Olsson-Francis , K., de la Torre, R. and Cockell, C.S. 2010. Isolation of novel extreme-tolerant cyanobacteria from a rock-dwelling microbial community by using exposure to Low Earth Orbit. Applied and Environmental Microbiology, vol. 76, No.7, pp. 2010, pp. 2115-2121.

Another paper by Professor Charles Cockell on the subject of a longer term survival of a Beer microbe is in press. The topic has been shown on BBC Television News (23rd August 2010), and is in the BBC website. Details are given above of the Upper Greensand and the overlying Beer Head Limestone (or Cenomanian Limestone) which crop out at the foot of the cliff on the southwest side of the beach. It is from here that the sample for space was obtained.

ACKNOWLEDGEMENTS

I am very grateful to Dr. Ramues Gallois for showing me the gypsum deposits in the Mercia Mudstone to the west of Branscombe Mouth. I very much appreciate receiving a copy of the paper on Beer cyanobacteria in space from Professor Charles Cockell. Dr. Laurence North at the National Oceanography Centre, Southampton University, has kindly shown me a special quality thin-section of the Beer Stone, which he is using in relation to his geophysical research on the rock. I am very grateful to Professor Charles Cockell and the BBC for opportunity to collect samples for a television report, and thus to become further involved with the Cretaceous of Beer. I thank friends who helped explore the cliffs of Beer more than half a century back, including Peter Roberts, the late Arthur Waite, Peter Robinson and others. In later years our daughter Tonya West has assisted on the cliffs of Beer.

References and Select Bibliography

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Ager, D.V. and Smith, W.E. 1965. The Coast of South Devon and Dorset between Branscombe and Burton Bradstock. Geologists' Association Guides, No. 23, 21 pp.

Ager, D.V. and Smith, W.E. 1973. The Coast of South Devon and Dorset between Branscombe and Burton Bradstock. Geologists' Association Guides, No. 23, Second revised edition, 23 pp.
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Ali, M.T. 1973. The Petrography of the Cenomanian Limestone and the Uppermost Upper Greensand in the Beer District, south Devon. Unpublished M.Sc. Thesis, London University, 224 pp. (not seen).

Ali, M.T. 1976. The significance of a mid-Cretaceous cobble conglomerate, Beer District, south Devon. Geological Magazine, vol. 113, pp. 151-158.
Abstract: A mid-Cretaceous cobble conglomerate in the Beer district, south Devon, is interpreted as a Lower Cenomanian beach deposit.

Ali, M.T., Gamble, H.J. and Smith, W.E. 1972. The Orbirhynchia Band in the Beer Stone Quarry, South Devon, with Notes on the Fish Fauna. Proceedings of the Geologists' Association, Vol. 83, Issue 3, 1972, pp. 313-326. Available online as a pdf file.
Abstract
During the autumn of 1969 deep temporary excavations in the Beer Stone Quarry exposed approximately 4 m. of deposits beneath the Beer Stone. These beds are correlated with the Orbirhynchia Band (plenus Subzone) and show the greatest development of this horizon hitherto known in South Devon. The sections are described with reference to stratigraphy, outline petrography and palaeontology, paying particular attention to the relatively abundant fish fauna.
[This is an expanded Turonian succession away from the Beer (ridge) axis. The deposits up to the top of Bed 2a are equivalent to Jukes-Brown Division C of the Cenomanian Limestone.]
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BRE. 2000. The British Stone List. See website: BRE: The British Stone List.
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Davies, G.M. 1918. Chromite in Beer Stone. Geological Magazine, Dec. 6, vol. 6, pp. 506-507.
The Beer Stone is a gritty limestone, made up largely of shell fragments with some foraminifera, quartz grains, and soft chalky material, occurring in the Rhynchonella Cuvieri [i.e. Mytiloides labiatus = Inoceramus labiatus]zone of the Middle Chalk near Beer Head in the south-east of Devon. It has long been worked for building purposes in underground galleries about one mile west of the village of Beer, and has been described by W. Hill and W. F. Hume in the Geological Survey memoir on the Lower and Middle Chalk. Dr. Hume records the following minerals as present in the insoluble residue of the stone: quartz, muscovite, glauconite, chalcedony, pyrites, tourmaline, rutile, andalusite, and possibly anatase. A. J. Jukes-Browne says the residue "contains a variety of minerals which have clearly been derived from land consisting of granite and Palaeozoic rocks such as occur in South Devon and Cornwall.
Samples collected by me last year in the underground workings have yielded additional evidence which is of some interest. A sample weighing 157 grammes was treated with dilute hydrochloric acid and yielded 3.1 per cent muddy residue and 0•32 per cent sand. The latter consists chiefly of quartz, up to 21 mm. diameter, the larger grains being well rounded. There is also a fair amount of felspar, mainly orthoclase, and of muscovite and glauconite, as well as a little flint. The sandy material was treated with bromoform, and the heavy residue was found to amount to 0-0.12 per cent of the stone. Coarse red and black grains are conspicuous in it. The former consist of limonitic matter, and the latter were tested in borax beads on the supposition that they might contain manganese. The beads, however, showed the fine green colour, somewhat yellowish in the oxidizing flame, characteristic of chromium. On crushing the black grains and examining them under the microscope the fragments exhibit the deep brown colour in transmitted light and the isotropic character of chromite. In several instances a green serpentine is associated with the chromite. The other heavy minerals present are tourmaline, staurolite, biotite, zircon, rutile, and andalusite, none of which call for special comment. A second sample gave 0.28 per cent sandy residue, but no chromite was seen in it. A thin section of the stone showed as many as seven fairly large quartz grains in an area of about half a square inch. Detrital chromite does not seem to have been recorded in any Cretaceous or older deposits in England. From this fact,as well as from the coarseness of the grains and the patchy nature of the occurrence, we may conclude that the chromite was derived directly from some area of ultra-basic rocks, possibly the Lizard, possibly an area now submerged beneath the English Channel; and the occurrence is of interest as showing that serpentines as well as granites were being eroded in Turonian times.
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Dove, J. 1992. Exeter: the geology of a cathedral. Geology Today, Volume 8, Issue 5, 1992, Pages 176-179.
Abstract: Cathedrals are geologically fascinating and that of Exeter is no exception. Outward appearances are deceptive; although the outer medieval walls are made of Greensand, the core is made of local Permian breccia and volcanics. Beer Stone is used less extensively than generally supposed, although it is important for carving. Nineteenth-century improvements in transport encouraged greater use of Cotswold and East Midland oolites for the cathedral repairs. Over time, these and local stones have weathered differentially, which has encouraged masons to return to Greensand for very recent repairs.
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Durrance, E.M. and Laming, D.J.C. (Editors) 1982 (reprinted 1985, paperback, and 1993). The Geology of Devon. University of Exeter Press. 346 pp. ISBN 0 85989 247 6.
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Edwards, R.A. and Gallois, R.W. 2004. Geology of the Sidmouth District: a brief explanation of the geological map. Sheet Explanation of the British Geological Survey. 1:50,000 Sheets 326 and 340 Sidmouth (England and Wales). NERC 2004. Keyworth Nottingham: British Geological Survey. 30pp. Obtainable from BGS, British Geological Survey Bookshop, online.
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Gale, A.S., Young, J.R., Shackleton, N.J., Crowhurst, S.J. and Wray, D.S. 1999. Orbital tuning of Cenomanian Marly Chalk Successions, towards a Milankovitch Time Scale for the Late Cretaceous. Philosophical Transactions of the Royal Society, London, A (1999), 357, pp. 1815-1829.
Outcrops of Cenomanian marly chalks in the Crimea (Ukraine) and SE England (UK), 2600 km apart, display conspicuous decimetre-scale rhythmicity and can be correlated by using 12 biostratigraphical events. Closely spaced samples from the two sections were used to generate long time-series of digitally captured grey-scale reflectance data. Spectral analysis of these data demonstrates that if the rhythmicity is assumed to be driven by precession (bedding cycles; mode at 20 ka), it is seen to be modulated by the short eccentricity cycle (100 ka bundles). The latter signal is expressed in the sediments by the occurrence of dark marls at precession minima occurring at eccentricity maxima. Although identified in the spectra, tilt (38 ka) and the long eccentricity cycle (400 ka) are not strongly expressed. Comparison of age modelled, unfiltered grey-scale data between the two sections reveals strikingly similar patterns, and enables the identification of a 80 ka hiatus in the UK chalks.
[This paper is not on the subject of Devon, but is very relevant to any study of the Cenomanian of those regions.]

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Gallois, R.W. 2001. The lithostratigraphy of the Mercia Mudstone Group (mid to late Triassic) of the South Devon coast. Geoscience in south-west England, Proceedings of the Ussher Society, Vol. 10, 195-204. By Dr. Ramues Gallois.

Gallois, R W. 2001. Field excursion to examine the geology and landforms of the Charmouth to Lyme Regis area, 3rd January 2001. Geoscience in south-west England, Proceedings of the Ussher Society, Vol. 10, 243-246.

Gallois, R.W. 2003. The distribution of halite (rock salt) in the Mercia Mudstone Group (mid to late Triassic) in south-west England. Geoscience in south-west England, Proceedings of the Ussher Society, Vol. 10, 243-246.

Gallois, R.W. 2004. The lithostratigraphy of the Upper Greensand (Albian, Cretaceous) of south-west England. Geoscience in south-west England, Proceedings of the Ussher Society, Vol. 11.

Gallois, R.W. 2004. Large-scale dissolution features in the Upper Greensand (Cretaceous) in south-west England. Geoscience in south-west England, Proceedings of the Ussher Society, Vol. 11.

Gallois, R.W. 2004. The stratigraphy of the Upper Greensand (Cretaceous) of south-west England. Geoscience in South-West England., vol. 11, pp. 21-19. By Dr. Ramues Gallois, Stoke Valley Road, Exeter.
Abstract:
The Upper Greensand Formation, in part capped by the Chalk, forms a broad, highly dissected plateau in east Devon and south Somerset. The formation is poorly exposed inland, but the coastal cliffs between Sidmouth and Lyme Regis provide the most extensive and most complete exposure of the Upper Greensand in Britain. De la Beche (1862) divided the formation in Devon in three parts, in ascending order the Cowstone Beds (or Sands), Foxmould and Chert Beds. A recent survey hasd confirmed that two of these three subdivisions (redefined here as members) and has added a third. Each of the proposed members is separated by a major erosion surface that marks a change in overall lithology. The proposed type sectiosn for all three are exposures in cliffs on the east Devon coast. The Foxmould Member, which includes the Foxmould and Cowstones of De la Beche, consists of weakly cemented sandstones that crop out mostly on steep precipitous cliffs formed by the higher parts of the formation. The Chert Beds of De la Beche have been divided into two members, the Whitecliff Chert Member and the overlying Bindon Sandstone Member. Both are markedly more calcareous than the Foxmould Member and give rise to extensive sections that reveal marked lateral variations which reflect high energy, shallow-water, marine environments. The ages of the lowest and highest parts of the formation are well constrained by ammonite assemblages. However, much of the middle part of the succession, in particular the Whitecliff Chert Member, although locally rich in bivalves, gastropods and foraminifera, has yielded few in situ age-diagnostic fossils.

Gallois, R.W. 2007. The stratigraphy of the Mercia Mudstone Group succession (mid to late Triassic) proved in the Wiscombe Park Boreholes, Devon. Geoscience in southwest England, 11, 280-286.
The type sections of the Sidmouth Mudstone, Dunscombe Mudstone and Branscombe Mudstone formations of the Mercia Mudstone Group are the almost complete sections exposed in the cliffs between Sidmouth and Axmouth on the Devon coast. The partially cored Wiscombe Park No. 1 and No. 2 mineral-exploration boreholes, drilled by British Gypsum Ltd in 1972, were sited about 5.8 and 4.7 km north of the cliff sections respectively. The first of these penetrated the whole of the Sidmouth MudstOne and Dunscombe Mudstone formations and the lower part of the Branscombe Mudstone Formation. The lithological succession proved in the cored parts of the bore holes can be correlated with that exposed in the cliffs. Geophysical logs made through the full length of the boreholes enable the complete succession proved there to be correlated with that exposed in the cliffs. The calibrated geophysical logs have been used to correlate the succession at outcrop with those proved in uncored but geophysically logged hydrocarbon-exploration boreholes throughout the Wessex Basin. The Sidmouth Mudstone and Branscombe Mudstone successions proved in the Wiscombe Park boreholes are similar in thickness and lithology to those elsewhere in the Wessex Basin. In contrast, the Dunscombe Mudstone succession in the boreholes expands from 35 m in thickness to over 500 m by the addition of thick beds of halite in parts of the basin.

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Gallois, R.W. and Goldring, R. 2007. Trace fossils at the basal Upper Greensand (Albian, Cretaceous) unconformity surface in east Devon (southwest England) and the nature of the unconformity surface. Proceedings of the Geologists' Association, London, vol. 118, pp. 265-275. [may also be available as a pdf file]
Abstract:
Along the Devon coast the early Cretaceous Upper Greensand Formation rests unconformably on bioturbated firmground and hardground surfaces on mid-Triassic to early Jurassic rocks (Mercia Mudstone Group to Lias Group). The classification and interpretation of the burrows and borings preserved on and beneath these surfaces are discussed, and compared with those from similar bioturbated surfaces elsewhere in Europe. In east Devon, the nature of the preservation of these trace fossils is dependent not only on the nature of the substrate but also on that of the infilling materials. These range from poorly defined, irregular infillings composed of pebbly mudstone to well-defined casts of cemented fine-grained sandstone that preserve detailed external ornaments. The most prominent trace fossils recorded are regularly spaced, flask-shaped Gastrochaenolites ornatus Kelly & Bromley produced by an as yet unidentified bivalve that rotated during penetration. At Branscombe, where the Upper Greensand rests on Triassic mudstones, many of the crypts are ellipsoidal to subhemispheroidal in cross-section. Their producer(s) are also enigmatic. Some infillings contain fragments of Myopholas or Girardotia, bivalves that rotate during penetration of soft to firm substrates. These burrows were probably initiated above the unconformity surface and extended down into an already perforated and softened mudstone surface. A few burrows may be due to a burrowing coelenterate. Bioturbation at the sub-Albian unconformity is ubiquitous in southern and eastern England, and indicates that the erosion surface was available for colonization for a considerable period of time.

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Gallois, R.W. and Paul, C.R.C. 2009. Lateral variation in the topmost part of the Blue Lias and basal Charmouth Mudstone formations (Lower Jurassic) on the Devon and Dorset. Geoscience in South-West England, Vol. 12. 125-133.
Abstract:
The beds adjacent to the junction of the Lower Jurassic Blue Lias and Charmouth Mudstone formations are intermittently exposed in cliff and foreshore sections over a distance of 8 km on the east Devon and west Dorset coast on either side of Lyme Regis. Comparison of the successions in the highest part of the Blue Lias shows little lateral variation in thickness or lithology, with the exception of minor thickness changes in the two highest limestone beds. In contrast, the basal beds of the Shales-with-Beef Member, the lowest part of the Charmouth Mudstone, are laterally variable. Up to five beds of limestone that are present in the most westerly exposure in Devon are absent at the more easterly exposures in Dorset. This lateral variation does not appear to be related to contemporaneous fault activity. It is largely due to an unconformity at the base of the Shales-with-Beef that cuts out successively more of the basal beds when traced from west to east. The strict application of the definition of the Blue Lias Formation, currently taken at the top of the highest limestone in an interbedded mudstone-limestone succession, would include beds previously classified as Shales-with-Beef in east Devon.

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Gallois, R.W. and Porter, R.J. 2006. The stratigraphy and sedimentology of the Dunscombe Mudstone Formation (late Triassic) of south-west England. Geoscience in South-West England, 11, 67.

Gallois, R.W., Pirrie, D., Power, M.R. and Shail, R.K. 2004. Copper mineralised wood from the Mercia Mudstone Group, south-east Devon. Geoscience in South-West England, 11, 67.
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Groves, A.W. (Arthur W. Groves). 1931. The unroofing of the Dartmoor Granite and the distribution of its detritus in the sediments of southern England. Quarterly Journal of the Geological Society, London, vol. 87, pp. 62-96.
No abstract, so here is an example extract of the beginning:
THE Hercynian age of the Dartmoor granite is generally admitted, but little information has hitherto been available concerning the period at which this granite became contributory to sediments. The work described in this paper is an attempt to supplement this information by direct appeal to the sedimentary formations in the South of England. These have been systematically searched for detrital mineral species which, in respect of associations and both specific and varietal features, are in consistent agreement with the assemblage of accessory minerals characteristic of the Dartmoor granite as described by Dr. A. Brammall (1928). Both the coarse and fine constituents of the Permo-Triassic strata in the West of England have been investigated within recent years. In the South of England pebble-beds of post-Triassic age are rare. For the special purposes of this paper, strata investigated by other workers have been re-examined, and gaps have been bridged by the study of intervening horizons... [continues].

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Hancock, J.M. 1969. Transgressions of the Cretaceous Sea in South-West England. Transactions of the Ussher Society, vol. 3 (1969), pp. 61–83, 4 figs.

Hancock, J.M. (Jake M. Hancock). 1975. The petrology of the Chalk. Proceedings of the Geologists' Association, Vol. 86, Issue 4, 1975, pp 499-535.
Abstract:
Cretaceous chalk is a micritic limestone, mostly debris from planktonic algae, largely in micron-sized plates, but some still in their original circular groupings called coccoliths. Nearly all the material was deposited as low-Mg calcite which is stable at surface temperatures and pressures, which means that most chalk has been spared early lithification. Nevertheless, deep burial, high heat-flow or local tectonic stresses can each harden chalk, reduce the porosity and usually reduce the O 18: O 16 ratio.
During the Late Cretaceous there was little land in north-west Europe available for erosion because of high eustatic sea-levels, which carried pelagic sedimentation on to the continental shelves. A non-seasonal (probably arid) climate meant little erosion from what land there was. Hence the purity of the Chalk which was deposited in a sea of normal salinity, usually 100 to 600 m deep.
Instead of the homogeneous rock that it first appears to be, various chalks show rhythmic bedding, lamination bedding, submarine erosion surfaces and current-piled banks. All these may be cut by burrows. Early post-depositional solution has produced wispy-flasers of marl in the chalk, and has preferentially removed planktonic foraminifera. Early lithification has formed hard-grounds and allowed chalk-pebble conglomerates to be formed.
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Hart, M.B. 1982. The Marine Rocks of the Mesozoic. Pp. 179-203 in: Durrance, E.M. and Laming, D.J.C. (Editors) 1982 (reprinted 1985, paperback, and 1993). The Geology of Devon. University of Exeter Press. 346 pp. ISBN 0 85989 247 6. This section is by Malcolm B. Hart.

Hart, M.B. 2008. Cretaceous foraminifera from the Turonian succession at Beer, southeastern Devon, England. Cretaceous Research, Volume 29, Issues 5-6, October-December 2008, Pages 1035-1046. Life and the environment during the Cretaceous, 7th International Symposium on the Cretaceous. By Malcolm B. Hart, School of Earth, Ocean & Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, United Kingdom. Received 2 March 2006; accepted 4 May 2008; Available online 27 June 2008.
Abstract:
During Winter 2000/2001 a major cliff fall occurred at the back of the bay in Beer, southeastern Devon. In the subsequent remedial works the cliff was cleared of loose material prior to stabilisation works. This process provided a suite of samples from previously inaccessible parts of the cliff succession. By adding these samples to earlier suites of samples collected over the last 30 years it has been possible to improve our knowledge of the foraminifera of Turonian age in southwestern England.
The planktic foraminifera are, perhaps, the most significant component of the assemblages as many of the taxa recorded in Devon are of southern aspect and are relatively rare in others parts of the U.K. The planktic zonation recognised in this section is, therefore, almost identical with that recorded in Tethyan areas and a precise correlation can be generated. There are relatively large numbers of important taxa such as Helvetoglobotruncana helvetica, Dicarinella imbricata, Marginotruncana sigali, M. pseudolinneiana, M. coronata and M. schneegansi. The benthic foraminifera, by comparison, are relatively rare and are represented by a low diversity assemblage. This is typical of northwestern European chalk successions of Turonian age and is coincident with the highest sea levels of the Cretaceous. In the middle to late Turonian there is a dramatic shallowing event that is recorded world-wide at this level. The assemblage changes towards the top of the accessible succession at Beer record this significant, world-wide event.
Keywords: Turonian stratigraphy; Foraminifera; Global sea-level change,
Article Outline
1. Introduction
2. The Turonian succession
3. Investigation of the foraminifera
4. Depositional environments and sequence stratigraphy
5. Mid-Turonian sea level change
6. Summary
Acknowledgements
References

Hart, M.B., Simmons, M.D. and Williams, C.L. 1992. Sequence stratigraphy and sea-level changes in the mid-Cretaceous (Albian to Turonian) of southern England; a preliminary investigation.Proceedings of the Ussher Society, vol. 8, pp. 7-10
Abstract:
The detailed analysis of a sedimentary succession requires an accurate, viable, chronostratigraphic framework. This is especially true if sequence stratigraphy is to be attempted, as inaccuracies in dating will tend to invalidate any model and make relative sea-level changes impossible to assess. Within the Albian to Turonian interval there are available detailed and well-tested biostratigraphic zonal schemes based on both micro- and macro-palaeontology; across southern England two 'mega-sequences' are identified as well as many other regionally significant sequence boundaries. Maximum flooding surfaces are identified at a number of horizons, including a level within the Euhoplites lautus Zone, a level within the Hysteroceras orbignayi Subzone, a level low in the Stoliczkaia dispar Zone, a level in the mid - Mantelliceras mantelli Zone, a level within the M. dixoni Zone and in the mid-Acanthoceras jukes-brownei Zone. There may be other less well-defined maximum flooding surfaces and there are still some problems with the events in the Late Cenomanian.

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Hounslow, M.W., Posen, P. and Jenkins, G. 200? Undated. Magnetostratigraphy of the Middle and Upper Triassic: Mercia Mudstone Group, South Devon, UK. By Mark W Hounslow, Paulette Posen and Guy Jenkins (University of Lancaster and University of East Anglia). This seems to be a poster presentation, and it is available online at:
Magnetostratigraphy of the Middle and Upper Triassic Mercia Mudstone Group, South Devon, UK.
Example extract - beginning:
Introduction: Probably the most readily accessible and most complete outcrop exposures of the terrestrial Middle and Upper Triassic in Western Europe, occur on the South Devon coast between Sidmouth and Pinhay Bay (west of Lyme Regis; Figs. 1,2). The upper Triassic is mostly represented by the Mercia Mudstone Group (MMG), which is a monotonous sequence of 485m of mostly red, gypsum and dolomite bearing, lacustrine/loessic mudstones (Figs. 1,3). However the Blue Anchor and Arden formations are dominated by grey calcareous lacustrine mudstones. The biostratigraphy of the Devon MMG is constrained by a Rhaetian age (dinoflagellate) for the Penarth Group and topmost Blue Anchor Formation, a Carnian age (palynology) for the Arden Fm, and an Anisian age (tetrapods) for the underlying Otter Sandstone Fm.
Sampling: Detailed logging and re-evaluation of the entire sequence (outcrop and boreholes) as part of the re-mapping of the Sidmouth Geology Sheet, by the British Geological Survey, has allowed the construction of a composite lithostratigraphy. This was used as the base for magnetostratigraphic sampling at 210 horizons between Sidmouth and Culverhole Point (Fig. 2). These horizons cover ~385m of the lower, middle and upper Mercia Mudstone Group, with a remaining ~100m currently unsampled for magnetostratigraphy. The upper-most ~15m of the Blue Anchor Fm have not been evaluated for magnetostratigraphy, but equivalent horizons have been previously evaluated in North Somerset (UK) at St Audries Bay (Hounslow et al., in prep). In total 338 palaeomagnetic specimens were measured from the Devon Sections... [continues]
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Howe, J.A. 1910. The Geology of Building Stones. By J. Allen Howe, B.Sc., F.G.S. Edward Arnold, London. 455pp.
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Jarvis, I., Murphy, A.M. and Gale, A.S. 2001. Geochemistry of pelagic and hemipelagic carbonates: criteria for identifying systems tracts and sea-level change. Journal of the Geological Society, London, vol. 158, pp. 685-696.
Abstract:
The elemental (Si, Ti, Al, Mn, Ca, Zr) and carbon stable-isotope (delta l3C) geochemistry of a biostratigraphically well-constrained Cenomanian- Turonian (Upper Cretaceous) Chalk succession on the Isle of Wight, southern England, shows systematic variation that corresponds closely to a published sequence stratigraphic model for the Cenomanian. Six sequences and their constituent systems tracts, defined elsewhere using sedimentological criteria, are clearly distinguishable from bulk-sediment elemental profiles, and an additional Upper Cenomanian sequence previously identified in Spain is recognized in England from these geochemical data. The manganese curve is particularly instructive, exhibiting minima around sequence bonndaries and through lowstands, rising values from the transgressive surfaces through transgressive systems tracts, maxima around maximum flooding surfaces, and declining values through highstands. Silica and trace-element (Ti, Zr) aluminium ratios peak around transgressive surfaces and maximum flooding surfaces, indicating pulses of increased siliciclastic input. Positive delta 13C excursions are confirmed at the base of the Middle Cenomanian and spanning the Cenomanian- Turonian boundary but are not evident in other sequences. Variation in Mn is related to bulk sedimentation rate and detrital versus biogenic supply, which control the Mn flux and the efficiency of the diagenetic Mn 'pump' that leads to elevated Mn contents in sediments. Manganese peaks do not generally correlate with positive delta 13C excursions, and although near-coincident Mn and delta l3C peaks occur around the Cenomanian-Turonian boundary, the former is not necessarily linked to the oceanic anoxic event occurring at that time. The global oceanic Mn flux may have been enhanced during the Cenomanian as a result of hydrothermal activity during rapid sea-floor spreading and oceanic plateau formation. Elemental chemostratigraphy provides a new tool for developing sequence stratigraphic models in pelagic and hemipelagic carbonate successions.

Jarvis, I. and Woodroof, P.B. 1984. Stratigraphy of the Cenomanian and basal Turonian (Upper Cretaceous) between Branscombe and Seaton, SE Devon, England. Proceedings of the Geologists' Association, London, vol. 95, Issue 3, 1984, pp. 193-215.
The Beer Head Limestone (Cenomanian) and Seaton Chalk (Turonian-Coniacian) are erected as new formations. The type sections of the Beer Head Limestone and the lowest part of the Seaton Chalk are defined and described in detail. The Beer Head Limestone Formation is divided into 4 members: Pounds Pool Sandy Limestone (base), Hooken Nodular Limestone, Little Beach Bioclastic Limestone and Pinnacles Glauconitic Limestone (top). The base of each member is marked by a laterally extensive hardground surface. The formation is Lower Cenomanian at its base and Upper Cenomanian at its top but has a widespread hiatus at the top of the Little Beach Member, which appears to span much of the Middle Cenomanian. The Cenomanian-Turonian boundary is placed at the surface of the Haven Cliff Neocardioceras Hardground which marks the base of the Seaton Chalk. The lowest member of the Seaton Chalk Formation is the Connett's Hole Nodular Chalk Member, which here includes the low Turonian Mytiloides cf. opalensis (sensu Kauffman non Böse), M. mytiloides and M. cf. labiatus Zones, with the upper zone being absent locally. The overlying Beer Roads Flinty Chalk Member rests on the uppermost hardground of the lower Seaton Chalk, and lies within the mid-Turonian Inoceramus cf. cuvieri Zone. It is postulated that faulting and not folding best explains the depositional variations seen in the Cenomanian-Turonian of SE Devon.
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Jefferies, R.P.S. 1963. The Stratigraphy of the Actinocamax plenus Subzone (Turonian) in the Anglo-Paris Basin, Proceedings of the Geologists' Association, vol. 74 (1) (1963), pp. 1–33.
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Jukes-Brown, A.J. and Hill, W. 1903. The Cretaceous Rocks of Britain. Vol. 2. The Lower and Middle Chalk of Britain, Memoir of the Geological Survey U.K., (1903) VIII and 558, 8 plates, 87 figs.
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Kennedy, W.J. 1987. Late Cretaceous and early Palaeocene Chalk Group sedimentation in the Greater Ekofisk Area, North Sea Graben. Bull. Centre Rech. Prod. Elf-Aquitaine, vol. 11, 91-126.

Kennedy, W.J. and Garrison, R.E. 1975. Morphology and genesis of nodular chalks and hardgrounds in the Upper Cretaceous of southern England. Sedimentology, vol. 22, 311-386.
Abstract:
The Upper Cretaceous chalks of southern England are a thick sequence of rhythmically bedded, bioturbated coccolith micrites, deposited in an outer shelf environment in water depths which varied between 50 and 200–300 m.
The products of sea floor cementation are widely represented in the sequence, and a series of stages of progressive lithification can be recognized. These began with a pause in sedimentation and the formation of an omission surface, followed by (a) growth of discrete nodules below the sediment-water interface to form a nodular chalk, erosion of which produced intraformational conglomerates. (b) Further growth and fusion of nodules into continuous or semicontinuous layers: incipient hardgrounds. (c) Scour, which exposed the layer as a true hardground. At this stage, the exposed lithified chalk bottom was subject to boring and encrustation by a variety of organisms, whilst calcium carbonate was frequently replaced by glauconite and phosphate to produce superficial mineralized zones. In many cases, the processes of sedimentation, cementation, exposure and mineralization were repeated several times, producing composite hardgrounds built up of a series of layers of cemented and mineralized chalk, indicating a long and complex diagenetic history.
Petrographic study of early cemented chalks indicates lithification was the result of the precipitation of small crystals on and between coccoliths and coccolith fragments. By analogy with known occurrences of early lithification in Recent deeper water carbonates, the cement is believed to have been either high magnesian calcite or aragonite, and more probably the former. The vast scale of operations involved in the cementation process precludes carbonate in expelled pore fluids as the source of cement, whilst quantities of aragonite incorporated in sediment are also inadequate. This, plus the observed association of horizons of early lithification with pauses in sedimentation associated with omission surfaces suggests seawater as a source of cementing materials.
Stratigraphic studies indicate that processes of early lithification leading to hardground formation proceeded to completion in intervals to be measured in tens or hundreds of years. Regional studies suggest that early lithification characterized relatively shallow water phases associated with regional regression over the whole of the area, whilst in detail, the distribution of mature mineralized hardground complexes is strongly correlated with sedimentary thinning and condensation over small areas and the buried flanks of massifs. Early cementation in more basinal areas is typically in the form of nodular developments and incipient hardgrounds, whilst day contents in excess of a few percent appear to have inhibited early lithification.
The striking rhythmicity of hardgrounds and nodular chalks is no more than a particular expression of the overall rhythmicity of chalk sequences. The stage of early lithification reached in any instance is dependent on sediment type, the time interval represented by the associated omission surface and the degree of associated scour and erosion (if any).
Chalk hardgrounds differ from most others described in the geological literature in their widespread distribution (individual hardgrounds may cover up to 1500 km2), the presence of striking glauconite and phosphate replacements of lithified carbonate matrices, their frequently sparse epifaunas, and boring infaunas dominated by clionid sponges. These differences reflect the deeper water shelf setting of the chalk, and the more open marine, oceanic circulatory system, both strikingly different from the setting of other, shallower water hardgrounds.
Litho- and biostratigraphic variation in the chalk sequences of the area studied are summarized in an appendix.
[See Fig. 14 which shows a mineralised hardground and two units of nodular chalk at the top of the Mytiloides labiatus Zone, on the east side of Beer Harbour. ]

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Monteiro, J. F., Munha, J. and A. Ribeiro. 1988. Impact ejecta horizon near the Cenomanian-Turonian boundary, north of Nazare, Portugal. Meteoritics and Planetary Science, vol. 33, no 4, p. A112. 1998.

Monteiro, J. F., Ribeirol, A., Munhal, J., Fonsecal, P.E., Brandao Silva, J., Moital, C., and Galopim de Carvalho, A. (1988?). Ejecta from meteorite impact near the Cenomanian-Turonian boundary found at north of Nazare, Portugal. Lunar and Planetary Science, vol. 28.
This report summarizes preliminary studies on the ejecta found (by one of us, A.R.) near the Cenomanian-Turonian boundary in a coastal site north of Nazaré (western-central Portugal). If this is the ejecta from a meteorite impact, as it is proposed here, it must be related to the Tore Sea-Mount impact crater [1], situated 300 km to the west of the studied ejecta site. The ejecta is distributed in a small rectangular area of approximately 60 m × 10 m; it overlies a brecciated limestone of Cenomanian age, being covered by a several-meters-thick, very-poorly sorted, tempestite-like, Turonian and/or Senonian sandstone. The ejecta clasts show a homogeneous distribution along a narrow corridor that extends for 50 m with a general trend Nmg 60º E. The size of the clasts varies from millimetric up to 80 cm; each clastic boulder corresponds to a polymitic breccia comprising a variety of different lithologies. Their shape are diverse, but rounded, spherical, and ellipsoidal forms predominate.
The ejecta clasts display dominant black to brownish-yellow colors, quite often with a greenish tinge. The most notorious macroscopic phases are iron sulfides, but other minerals such as quartz fragments and calcitic nodules are also visible in hand specimen. Optical (reflected and transmitted light) and SEM-EDX analyses indicate the occurrence of pyrite, two unindentified iron oxides, quartz, calcite, and devitrified glass; however, in contrast with the intersample mineralogical monotonous composition, several different textures were observed. One of the major components of the silicate phase is diapletic glass; this glass can be found in the breccia matrix and as a major fraction within recrystallized quartz fragments making up to 40% modal of the ejecta samples. The diapletic glass fragments have a brown color and characteristically they are surrounded by dark halos.
Quartz shocked crystals are very common and a few grains also display optical features suggesting an internal organization into "planar elements." Small inclusions of a SiO2 phase also occur within diapletic glasses; these inclusions are characterized by higher refractive index than the surrounding glass and closely resemble the cryptocrystalline coesite occurrence from the Coconino Sandstone at Meteor Crater [2].
Impact melt features were also observed being dominated by trachytic type (microlite) textures; however, felsitic (cryptocrystalline) textures are also present. The actual microlites are now composed of quartz and calcite, but they could represent pseudomorphs after previous mineral phase(s). In spite of the lack of knowledege that still exists on the detailed stratigraphy, it is certain that the ejecta material was deposited close to the Cenomanian-Turonian boundary, at about 91 m.y. Significantly, the Nazaré phenomena coincides with a well known stepwise extinction [3] and with a global Ir anomaly [4]. [..continues with references].

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Morris, Steven 2007. Storm grows over Napoli's threat to World Heritage Coast. The Guardian Newspaper, Saturday, January 27, 2007, pp. 16-17. [re wrecked container ship, the MSC Napoli, causing major oil and container pollution off Branscombe, near Beer and Sidmouth, Devon. Bound for South Africa it suffered structural damage in the Atlantic Ocean in the storm of 18 January 2007. It was then heading for repair in Portland Harbour but, in danger of sinking, was beached about a mile south of Branscombe in January 2007.]
Example extracts: There were growing calls yesterday for an inquiry to establish why the stricken cargo ship the MSC Napoli was towed into one of Europe's most precious marine environments. Politicians and marine experts expressed concern that the decision to try to haul the vessel, loaded with oil and containers, some of which contained hazardous substances, into a port 140 miles from where it was holed. Questions are being tabled in the House of Commons, and the EU commissioner for transport, Jacques Barrot, is planning to send a teain to look into the incident. Environment experts were given little or no time to make the case against beaching the vessel off the coast of Devon before it was dragged on to the seabed last Saturday. Visiting the site of the drama yesterday, the shadow environment minister Greg Barker said the transport department would have to explain why the Napoli had been taken into Lyme Bay. He said he was very concerned about the long-term damage that could be caused to the Devon and Dorset coast, a world heritage site. "There remains a serious danger to the delicate maritime environment on the Jurassic Coast," he added. Adrian Sanders, Liberal Democrat MP for Torbay, said: "It was 50 miles off the Lizard [in Cornwall] in international waters. It must have been known there was a danger the vessel might have to be beached. There are other ports it could have reached before it got into trouble 90 miles away in Devon.... [continues]

[Sequence of Events]

Thursday January 18, 10.30am
Falmouth coastguard receives mayday call from MSC Napoli, foundering 45 miles south-east of the Lizard. Crew abandons ship and it is towed into Lyme Bay.

Saturday January 20, 11.25am
Large cracks on either side of Napoli have widened. Despite concerns by environment experts, the vessel is beached a mile off Branscombe beach in Devon at 2pm.

Sunday January 21, 12.03am
Gales sweep in and throw 103 containers into the sea, and on to the beach. Attempts to pull the vessel harder aground cause a 50-tonne oil leak creating a five mile slick.
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Mortimore, R.N. and Duperret, A. 2004. Coastal Chalk Cliff Instability. Geological Society of London, 173pp. (see particularly fig.1 on page 4).
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Olsson-Francis, K., de la Torre, R. and Cockell, C.S. 2010. Isolation of novel extreme-tolerant cyanobacteria from a rock-dwelling microbial community by using exposure to Low Earth Orbit. Applied and Environmental Microbiology, vol. 76, No.7, pp. 2010, pp. 2115-2121.
Abstract: Many cyanobacteria are known to tolerate environmental extremes. Motivated by an interest in selecting cyanobacteria for applications in space, we launched rocks from a limestone cliff in Beer, Devon, United Kingdom, containing an epilithic and endolithic rock-dwelling community of cyanobacteria into low Earth orbit (LEO) at a height of approximately 300 kilometres. The community was exposed for 10 days to isolate cyanobacteria that can survive exposure to extreme radiation and desiccating conditions associated with space. Culture-independent (16S rRNA) and culture-dependent methods showed that the cyanobacterial community was composed of Pleurocapsales, Oscillatoriales, and Chroococcales. A single cyanobacterium, a previously uncharacterised extremophile, was isolated after exposure to LEO. We were able to isolate the cyanobacterium from the limestone cliff after exposing the rock-dwelling community to desiccation and vacuum (0.7 x 10 to the minus 3 kPA) in the laboratory. The ability of these organisms to survive the conditions in space may be linked to the formation of dense colonies. These experiments show how extreme environmental conditions, including space, can be used to select novel microorganisms. Furthermore, it improves our knowledge of environmental tolerance of extremophilic rock-dwelling cyanobacteria.
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Perkins, J.W. 1971. Geology Explained in South and East Devon. David and Charles, Newton Abbott. 192 pp.
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Rowe, A.W. 1903. The zones of the White Chalk of the English coast. III. Devon. Proceedings of the Geologists' Association, London, 18, 1-52.
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Scott, J. and Gray, G. (John Scott and Gladys Gray). Beer Quarry Caves: Out of the Darkness: A brief history and description of the Old Stone Quarry, Beer. 21 pp. No date given, but on sale in 2010 (perhaps several years older). Small but informative booklet, with good illustrations, that can be purchased at the entry shop of the caves and quarry on the road from Beer to Branscombe.
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Smith, W.E. 1957a. Summer Field Meeting in South Devon and Dorset. Proceedings of the Geologists' Association, London, vol. 68, part 2, pp. 136-152. Date of field meeting: 20-27 August, 1955. Directors of the field excursion: W.E. Smith, D.V. Ager and D.J. Shearman.

Smith, W.E. 1957b. The Cenomanian deposits of south-east Devonshire: the Cenomanian Limestone of the Beer District, South Devon. Proceedings of the Geologists' Association, London, vol. 68, part 2, pp. 115-135. By William E. Smith.
Abstract: In the cliff-sections between Whitecliff (Seaton) and Hooken Cliff (SW. of Beer) the thickness of the Cenomanian Limestone varies considerably. At the rear of Pound's Pool Beach and at the end of a small point on the west side of Beer Beach it is only about one foot thick. In contrast, at Beer Head and Hooken Cliff it is very much thicker, reaching a maximum of nearly thirty feet in the latter place. These variations in thickness appear to be related to a NNE.-SSW. axis of intra-Cretaceous periclinal uplift passing from Beer Beach to Little Beach (west of Beer Head). The Cenomanian Limestone is thinnest and least complete over the crest of the uplift. The thicker, more complete successions at Beer Head and Hooken Cliff lie on opposite (i.e. ESE. and WNW.) sides of the axis. There is evidence of intermittent small-scale tectonic activity along the axis before, during and after Cenomanian times. On the other hand the Tertiary fold known as the Beer Syncline appears to have been superimposed on the Cretaceous rocks and structures.

Example extract: Introduction:
The Cenomanian Limestone is the name given to the few feet of sandy limestones which occur between the Upper Greensand and Middle Chalk in South Devon. The stratigraphical position of the formation shows that it represents, at least in part, the much thicker Lower Chalk of the more easterly counties of England. In southern Dorset the Cenomanian consists of blocky grey marly chalk with a well-marked sandy glauconitic basement-bed. This facies persists as far west as Membury (near Axminster) where it is at least fifty feet thick. In the coastal sections about eight miles south of Membury, however, no such deposits are present, the sole representative of the Cenomanian being the above-mentioned sandy limestones. These are not only much thinner than the Lower Chalk of Dorset but, in the sections between Lyme Regis and Sidmouth, they undergo rapid lateral changes in thickness. In places, for example at the extreme western end of Charton Cliff, the formation is absent. In other places, as in the Hooken Landslip, it reaches a thickness of nearly thirty feet. Over most of the outcrop, however, the thickness ranges from one to four feet (plate 4A). The Cenomanian Limestone here in South Devon provides us, therefore, with a remarkable example of condensation and lateral change both in facies and thickness. Comparatively little work has been published regarding the formation. Meyer (1874) tabulated and numbered the Cretaceous strata around Beer and gave a faunal list for each of his subdivisions. The beds numbered 10, 11, 12 and 13 by him appear to represent the strata which were later grouped as the Cenomanian Limestone.
In the Geological Survey Memoir relating to the country near Sidmouth and Lyme Regis (Woodward & Ussher, 1911), the description of the beds is based upon observations made by Jukes-Browne. Indeed, this author is responsible for the only published data regarding the lateral variations of the formation (1896 and 1903). He (1903, pp. 130-44) divided it into three subdivisions, A, Band C, each of these subdivisions being characterised by a distinctive lithology and fauna. They were regarded by him as being separated from each other and from the contiguous deposits by erosionsurfaces. Jukes-Browne ascribed the remarkable lateral variation in thickness of his subdivisions to variable depth of erosion during successive erosion-periods. In a footnote (1903, p. 351), however, he suggested that differential (unequal) penecontemporaneous earth-movements may also have been a factor.
The present paper describes in greater detail the lateral variations in the thickness of the Cenomanian Limestone between Whitecliff, Seaton and the Hooken Landslip, west of Beer Head (Fig. 1). It also suggests an explanation for the remarkable lateral variations in thickness which occur between these localities... [continues].

Smith, W.E. 1961. The Cenomanian Limestone and contiguous deposits west of Beer. Proceedings of the Geologists' Association, London, vol. 72, pp. 91-134, 3 pl.

Smith, W.E. 1962. Easter Field Meeting: the Upper Albian and Cenomanian Deposits of Wessex. Proceedings of the Geologists' Association, London, vol. 73, pp. 335-352.

Smith, W.E. 1965. The Cenomanian deposits of south-east Devonshire; the Cenomanian Limestone east of Seaton. Proceedings of the Geologists' Association, London, vol. 76, No. 1, pp. 121-136.
Abstract:
The distribution, lithology and regional variations in the thickness of the Cenomanian deposits in south-east Devon are summarised. Three distinctive facies are recognised, viz. (i) the Lower Chalk facies, (ii) the Cenomanian Limestone facies, and (iii) the calcareous sand or Wilmington facies.
A detailed description is given of the lateral variations in the lithology, thickness and certain palaeontological features of the cliff-sections and inland exposures of Ceno-manian rocks west of Beer. Between Hooken Cliff and Branscombe West Cliff the lateral variations in the lithology and thickness of the Cenomanian rocks are related to the Branscombe Mouth Ridge. This was a submarine ridge which periodically developed in the Branscombe Mouth region as a result of anticlinal earth movements along an elongated pericline, possibly of asymmetric type, and with an axis elongated in a general N.- S. direction. The greatest uplift along this axis occurred in late Cenomanian times and led to the formation of a ridge that was not buried beneath Middle Chalk deposits until after the deposition of the Inoceramus labiatus Zone. The anomalous fauna of the Inoceramus labiatus Zone west of Branscombe Mouth is ascribed to the influence of the Branscombe Mouth Ridge.
The thick Cenomanian deposits at the eastern end of Hooken Cliff accumulated in a tectonically stable area or depression lying between the Branscombe Mouth Ridge and the Beer Beach-Little Beach Ridge (Smith, 1957a). They display lithological features indicative of current activity that was generally weaker than that responsible for vigorous erosion over the adjacent ridges. The thick Cenomanian deposits in the Bovey Lane sand-pit, about one mile north-west of Beer, include beds of Wilmington facies and appear to have accumulated in another depression connected with the northerly plunge of the Branscombe Mouth Ridge. The lateral variations in the thickness of the Cenomanian Limestone west of Branscombe Mouth are mainly due to the presence of undulating erosion-surfaces, including comparatively deep scour-channels in the top of the Upper Greensand. The thin and incomplete development of the Cenomanian Limestone at Donkey Linhay may, however, be indicative of small-scale intra-Cenomanian anticlinal earth-movements in that region.

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Thomas, H.H. 1909. A contribution to the Petrography of the New Red Sandstone in the West of England. Quarterly Journal of the Geological Society, London, vol. 65, pp. 229-245. By Herbert Henry Thomas, M.A., B.Sc., F.G.S. (Read March 10th, 1909).
The following example text from p.242 brings out the major conclusions, including the interesting aspect of a distant source of staurolite:

From a study of the distribution and quantity of certain mineral species, it is possible in most instances to gather some idea of the relative amounts of material derived from various sources. This is more especially true in the case of the Lower Breccias and Sandstones and the Pebble-Bed. The material forming the marls, however, as might be expected from its finely comminuted nature, appears to have been supplied from an directions, and by a greater variety of rocks than those yielding detritus towards the formation of the other New Red sediments.
With regard to the source of the various mineral species it is most difficult to speak, except in certain cases; but, so far as can be judged, all the minerals detected in the New Red deposits, with the exception of staurolite, could be supplied by the older rocks of the West of England. The greater abundance of such minerals as blue tourmaline, topaz, rutile, and brookite appears to indicate that the rocks in which they occur were largely derived from the granite masses of Devon aud Cornwall, but more especially points to their attendant metamorphic rocks aud veinstones.
The garnets of the New Red deposits are clearly in no way dependent on the distribution of staurolite, but, on the contrary, are of most frequent occurrence in the northern part of the district where staurolite is less abundant. The fact that garnet, in the Pebble-Bed, makes its appearance together with an increased proportion of blue tourmaline, points to its derivation, at any rate in part, from the metamorphic rocks surrounding the West of Englnnd granites. Its absence from certain horizons might be accounted for, either by the direction of the sediment-bearing currents, or by the extremely local occurrence of garnets in the metamorphic aureoles of this district. It is only where subordinate calcareous bands of the Devonian and Carboniferous rocks and diabase-intrusions come within the influence of the granites that this mineral has been produced. It is not suggested that all the garnets in the New Red rocks were supplied by these metamorphic areas; but, should it be so, it would appear from the distribution of this mineral that all the New Red rocks of North Devon and West Somerset were formed in part of material carried from the west and southwest.
The Lower Breccias have always been considered as deposits derived from sources near at hand, for, as pointed out by De La Beche, Godwin-Austen, Conybeare and Phillips, and Mr. R. H. Worth, among the rock-fragments found in them are numerous examples of well-known rock-types present in Devon. The minerals and grains forming the finer material of these deposits point towards the same conclusion; but, in addition, especially in South Devon, they suggest strongly the influence of certain rock-masses non existent within the south-western area as now known. There is, also, nothing in the finer material to prove that the granite-masses themselves were undergoing denudation at the time when the Lower Breccias were being deposited.." [continues]
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Woodward, H.B. and Ussher, W.A.E. 1899. Excursion to Seaton, Sidmouth, and Exeter. Proceedings of the Geologists' Association, London, vol. 16, pp. 133-153. By Horace B. Woodward, F.R.S., F.G.S. and W.A.E. Ussher, F.G.S.
[Example extract - pp. 133-134]
"Twenty-eight years ago, Prof. James Buckman and Mr. J. Logan Lobley conducted an excursion of the Geologists' Association to the Yeovil district, and spent a short time on their fourth and last day along the cliffs east of Seaton. It seems strange, however, that forty years should have elapsed since the foundation of this Association before any expedition was made to the South Devon coast between Seaton and Exmouth, with its iringes of Blackdown Beds and its famous pebble-bed of Budleigh Salterton.
In 1889 an excursion was made to Lyme Regis, under the guidance of the present Director, and the members then advanced as far as the eastern portion of the Great Landslip. It was now planned to continue the exploration from the Landslip westwards to the mouth of the Exe.
On Thursday evening, March 30th, the members of the party, which numbered nearly forty, arrived at the Royal Clarence Hotel, Seaton. On Friday, March 31st, the members started at 9 a.m. along the esplanade to Axmouth Bridge, where the Director pointed out that the trend of the beach turned the outlet of the river eastwards, and had been the means of choking the harbour of the once flourishing little fishing-town. At the close of the last century, a large tract of salt marshes extended above Axmouth, but these had been drained to the advantage of the neighbourhood. In far earlier times, when the river was more potent in action, spreads of valley-gravel were laid down, and from these at Broom, in the parish of Hawkchurch, above Axminster, some fine palaeolithic implements, fashioned from Upper Greensand chert, had been obtained. Remains of Mammoth had been found in the Sid Valley, further west.
The party now proceeded by Squire's Lane to the lime-kiln beyond the Coastguard Station, where the Middle Chalk, zone of Rhynchonella cuvieri, had been noted by Mr. A. J. Jukes-Browne. This division cropped out along the 300 ft. contour-line. Several specimens of Inoceramus mytiloides and poor examples of the characteristic Rhynchonella were obtained. Passing on through Barn Close and Stony Close Lanes, a pleasant walk over the grassy Chalk-plateau, here, in places 400 ft. high, led to the western end of the Great Landslip at the Bindon Cliffs. The view eastwards through the chasm was grand and striking, the slipped masses of Chalk and Greensand forming a platform about 100 ft. lower than the cliffs from which they had broken away. As some account of this Great Landslip, which happened at Christmas, 1839, has already been published by the Association, no particular description need now be given.
Leaving the chasm, the members proceede4 a short distance westwards along the brow of the cliffs and descended by a foot-path to the shore a little west of Culverhole Point. Here in the low cliffs fringing the beach a fine section of Rhaetic Beds was exposed."
[continues]

Woodward, H.B., Ussher, W.A.E. and Jukes-Browne, A.J. 191l. The Geology of the Country Near Sidmouth and Lyme Regis. Memoirs of the Geological Survey, England and Wales, Explanation of Sheets 326 and 340. Second Edition, His Majesty's Stationery Office, London. 102 pp.
Example extract (p.57 on Chalk at Beer):
"In the grand headland at Whitecliff, between Seaton and Beer, a fine sequence of Chalk may be observed. In the bluff known as Annis' Knob the Upper Chalk may be conveniently studied. Here the formation is remarkably nodular, the nodules being some of flint with thick white siliceous crust and a tiny nucleus of black flint, while a large number are composed of more or less siliceous chalk. A prominent band of black flints near the middle of the bluff was taken by Mr. Jukes-Browne as a convenient divisional plane between the zones of Micraster cor-testudiarium and Holaster planus, but Dr. Rowe takes the limit 10 feet higher.
At a lower level in the cliff which forms the northern side of Beer Harbour, the best section in Devon of the Middle Chalk is exposed. The upper part belongs to the zone of Terebratulina, about 90 feet; and the lower part bordering the shingle beach, about 30 or 40 feet, to the zone of Rhynchonella cuviera [Inoceramus labiatus]. In this latter zone, which extends to the natural archway further east, is included the representative of the Beer Stone, noted by Mr. Jukes-Browne as consisting of two layers of somewhat nodular chalk about 5 feet thick. Reefs of the Lower Chalk a few feet thick occur beneath, resting on a floor of Upper Greensand... "[continues]
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Wray, D.S. and Gale, A.S. 2006. The palaeoenvironment and stratigraphy of Late Cretaceous Chalks. By David S. Wray and Andrew S. Gale. Proceedings of the Geologists' Association, 117, 145-162.
Abstract: Since the publication of Hancock's 'the Petrology of the Chalk' there have been numerous developments in our appreciation of the palaeoenvironment and stratigraphic correlation of the UK Chalk. This work presents a review of some of the key developments over the last 30 years. Our detailed understanding of Chalk lithostratigraphy and advances in our understanding of chalk sedimentation indicate that large-scale mass transport and re-sedimentation of chalks by low-angle suspension flows is required to explain the observed thickness variations. The provenance of clay minerals and the process of flint and granular phosphate formation are discussed. The growing importance of isotopic studies in high resolution stratigraphy and improving our understanding of the late Cretaceous oceans and climate are emphasized. Developments in lithostratigraphic studies and recent proposals for a new stratigraphic division of the Chalk in the UK are evaluated. Authors' address - Department of Earth & Environmental Sciences, School of Science, The University of Greenwich, Chatham Maritime, Kent ME4 4TB, UK.

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Webpage - written and produced by:

Ian West, M.Sc. Ph.D. F.G.S.

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at his private address, Romsey, Hampshire, kindly supported by Southampton University,and web-hosted by courtesy of iSolutions of Southampton University. The website does not necessarily represent the views of Southampton University. The website is written privately from home in Romsey, unfunded and with no staff other than the author, but generously and freely published by Southampton University. Field trips shown in photographs do not necessarily have any connection with Southampton University and may have been private or have been run by various organisations.