The biggest erratic in Pembrokeshire?

 The Sleek Stone -- a famous monoclinal fold in the Lower Coal Measures.  The erratic is to the north of this little peninsula -- best approached at low tide......

On thumbing through those Geological Survey Memoirs, I discovered a note in the Milford Memoir about a giant erratic beneath the cliffs of Broad Haven (the one on St Bride's Bay) made of "columnar blue quartz-porphyry" and derived almost certainly from Ynys Bery / Ramsey Island.  Its dimensions are approx 3m x 3m x 3m -- which would make it a 50-tonner by my estimation -- and comparable to the giant erratic at Freshwater Gut, near Croyde in Devon.  It's located about 100 yards north of the Sleek Stone, Broad Haven.

I have never seen it myself, but I feel an expedition coming on.........

The Sleek Stone is at the south end of this satellite image, and the giant erratic must be in the bay which we see here in the centre of the photo.

Ramsey Island as a major source of erratics?

I have been struck, in my recent reading, by the number of times that Ramsey Island gets a mention as a possible erratic source.  Most recently I was looking at the paper by Bevins and Donnelly about the Storrie collection of erratics that were gathered up from the Pencoed area of Glamorgan.  They describe a number of sub-rounded fragments made of "mud-rich volcanic debris-flow" material and assign Ramsey Island as a possible source.  They also describe other rock types (gabbro and rhyolitic tuff) from the adjacent St David's Head area.  They also describe three "far-travelled boulders" from the Cowbridge area which are ignimbrites very similar to those found on Ramsey.

Add to this Sid Howells's instinct that quite a few of the erratic pebbles collected on Flat Holm are from Ramsey (still to be confirmed by detailed analyses)...........

And add to this the speculation as to Ramsey origins for some of the more unusual erratic pebbles and boulders collected by the Geological Survey field researchers in the period 1904-21.

Griffiths (1940) identified two erratic types in south Pembrokeshire that he traced to Ramsey Island.

Finally there are the suggestions -- in my mind at least -- that some of the far-travelled erratics on Lundy Island and in the Baggy Point - Croyde - Saunton area might also have come from Ramsey.  Much more thin-section work is needed!

Should we be surprised if Ramsey Island turns out to be rather an important source for far-travelled erratic material?  Not a bit of it.  If Irish Sea Ice was coming in from St George's Channel -- ie from the north-west --  at a time when there was no sea water in the vicinity at the time, ice would have been rising up from a bedrock floor beneath -100m OD to override the western cliffs of the island which are over 100m high.  So ice would have been flowing UPHILL on quite a steep gradient, from NW towards SE, over a distance of not much more than 20 km, and rising 200m (c 660 ft) in the process.  Perfect conditions for compressive ice flow, and perfect conditions for the entrainment of erratics.

The Glaciation of South Pembrokeshire

On hunting through some old box-files I have rediscovered photocopies of the "superficial deposits" chapters from the Memoirs of the Geological Survey, published between 1909 and 1921.  The surveyors working in West Wales were A. Strahan, TC Cantrill, EEL Dixon, OT Jones and HH Thomas -- all very famous geologists who knew their stuff.

The map reproduced above is from the Haverfordwest Memoir (1914) which shows erratic distributions across SE Pembrokeshire.  Note the two "erratic fans" marked.  The authors do not suggest that there are no relevant boulders dotted about outside those fan limits -- but the lines show where the greatest concentrations are.  The spotted "diabase" (dolerite) is of course from eastern Preseli and the "hornblende - porphyrite" is deemed to have come from the Portpatrick district on the Mull of Galloway in western Scotland. 

There is a huge amount of detail in these Memoirs -- and I'm still quite confused as to how much of South Pembrokeshire might have been affected by the Irish Sea Glacier in Devensian times.  watch this space......

Another thing that intrigues me is that HH Thomas was part of this team, which produced its final report in 1921 (The Pembroke and Tenby Memoir) -- that was the same year as Thomas's famous lecture about the bluestones to the Society of Antiquaries.  He claimed of course that glacier ice could not have carried the bluestones to Salisbury Plain -- but he and his colleagues must have known that "diabase" and many other erratics were transported by ice far to the east of Pembrokeshire, since the Memoirs mention Irish Sea erratics in the Swansea area and near Pencoed in the Vale of Glamorgan.  I wonder what conversations went on behind closed doors between these guys, who must have spent hundreds of hours together on their fieldwork and in local bars and hotels..........

Croyde erratics etc -- historic photos

Here are three historic photos -- I used them in my doctorate thesis in 1965, and as I recall they were taken on a field trip in 1963.  There are some famous names here in the field party!  I think I can recognize Prof Nick Stephens, Prof Ron Waters and Prof Denys Brunsden.......

The top photo shows the giant erratic at Freshwater Gut.  The middle one shows the stoneless clays from Brannans Clay Pit at Fremington.  The lower photo shows the sandrock layer exposed in the cliffs near Saunton -- the sandrock rests on an ancient wave-cut platform, and gives us a classic illustration of what an unconformity looks like......

Rhyolite pebbles on Lundy island -- and limestone too

This map from Rolfe et al, 2012 is generalised but nonetheless interesting, since it suggests an ice limit impinging onto Salisbury Plain not far from Stonehenge. 

I've been looking at these two papers by Chris Rolfe and colleagues -- and am reminded of the presence of rhyolite pebbles in the erratic assemblage.  They appear convinced that the rhyolites are not local, and suggest they might have come from Skomer Island off the coast of Pembrokeshire.   So now we have rhyolites on Lundy Island and on Baggy point, and I'm pretty sure there are rhyolites on Flat Holm as well (that may be confirmed when Sid Howells has completed the identifications of the samples collected there during our autumn 2014 visit.)

There are limestone erratics too.  Could they have come from South Pembrokeshire?

This all starts to look interesting..... but remember that these papers refer to an EARLY DEVENSIAN glaciation of Lundy.  That looks out of synchronisation with the Late Devensian glaciation which reached the Scilly Isles.  Either there are problems with dating techniques, or there was a sort of pulsed behaviour, with different parts of the Irish Sea Glacier reaching their maxima many thousands of years apart.......  No doubt this will be sorted out eventually.

But as ever, what happened in the Devensian can give us some guidance to what happened in the generally much bigger Anglian Glaciation. 

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TIMING OF THE MAXIMUM EXTENT OF LATE PLEISTOCENE GLACIATION IN N.W. EUROPE: EVIDENCE FROM LUNDY
by CHRIS J. ROLFE, PHILIP D. HUGHESAND ANTONY G. BROWN,  Journal of the Lundy Field Society, 4, 2014, pp 7-18.

ABSTRACT
This paper presents geomorphological and cosmogenic isotope evidence for the glaciation of Lundy. 26Al/10Be analyses from glaciated bedrock surfaces reveal an exposure age of c. 35-40ka. This challenges the long-established view that the last glaciation this far south must belong to Middle Pleistocene, such as the Anglian Stage (c. 480-420 ka), when ice reached as far south as London. Instead, the findings suggest glaciation of Lundy during the last ice age (Devensian Stage). However, the ages from Lundy suggest that the ice sheet in this area was at its largest extent well before the global Last Glacial Maximum at c. 26-21 ka.


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Rolfe, C.J., Hughes, P.D., Fenton, C.R., Schnabel, C., Xu, S., Brown, A.G., 2012. Paired 10Be and 26Al exposure ages from Lundy: new evidence for the extent and timing of Devensian glaciation in the southern British Isles. Quaternary Science Reviews 43(2012): 61-73.

ABSTRACT
Lundy lies in a strategic geographical position for understanding the glacial history of the British Isles. The island bears evidence of glaciation, largely in the form of ice-moulded bedrock and glacially- transported boulders e an unusual occurrence this far south in the British Isles. Irish Sea ice penetrated the western Bristol Channel overriding Lundy from the northwest during the last phase of glaciation in this area. The results of paired terrestrial cosmogenic nuclide analyses (26Al/10Be) constrain the timing of this extensive glaciation and provide, for the first time, an age for the exposure of Lundy granite following deglaciation. The results from nine paired samples yield 26Al/10Be exposure ages of 31.4-48.8 ka (10Be) and 31.7-60.0 ka (26Al). This challenges the view that any glaciation this far south must belong to Middle Pleistocene glaciations, such as the Anglian Stage (c. 480-420 ka) and a Devensian age for the last glaciation is consistent with findings from the Isles of Scilly further south. However, the findings suggest early-mid Devensian (marine isotope stage (MIS) 4-3) glaciation of Lundy. It also implies that the island was exposed or covered for a short time by non-erosive cold-based ice at the global Last Glacial Maximum (LGM) during MIS 2 (26-21 ka). The potential exposure of the island throughout MIS 2 contrasts with the evidence from the Isles of Scilly and the Celtic Sea, which were glaciated at the LGM.

EXTRACT

Two (pebble) samples had similar physical properties (fine-grained light blue-grey clasts) with similar geochemistry with SiO2 contents of 75.8% and 79.5% and combined Na2O and K2O of 2.6% and 3.3%. These samples are similar to some rhyolites. On Lundy, rhyolite dykes are known to be present -- including in the north of the island near the gravel spreads where the clasts were found (Thorpe and Tindall, 1992). However, the local rhyolites have much higher values of combined Na2O and K2O (7.8e10.5%). Furthermore, the clasts have much higher iron oxide content (Fe2O3: 6%) than most of the Lundy rhyolites that have otherwise comparable geochemistries (Fe2O3: 1e2%). The clasts have a closer geochemical composition to rhyolites from the thick rhyolite sequences of the Skomer Volcanic Group off the westernmost coast of Pembrokeshire (e.g. Thorpe et al., 1989) although the precise origin remains unknown.

In addition to the siliceous clasts analysed using XRF, several limestone clasts collected from the gravel spreads are clearly erratics since no carbonate bedrock lithologies are found on or near Lundy. Given that rhyolites, quartz/quartzites, siliceous sedimentary and carbonate limestones are common lithologies, a wide range of sources are possible as noted in the previous paragraphs. Nevertheless, the presence of these erratic clasts is consistent with transport and deposition in association with an Irish Sea Ice Sheet. The fact that the clasts are well-sorted into cobbles and gravels and predominantly rounded suggests deposition by water. The presence of these deposits on the watershed is consistent with sediment release at the apex of bedrock obstacles in subglacial channels (cf. Lesemann and Brennand, 2009).

The Erratics at Baggy Point, Croyde and Saunton (2)

 This is a map from Olwen Williams-Thorpe which represents the ideas of Geoffrey Kellaway.  You can see the location of Lundy Island just above the "100 km" symbol, and the the Baggy Point area to the right of that, where the longer arrow crosses the coast.  Note that Kellaway speculated about a "Scottish ice stream" with very far-travelled erratics crossing the Devon coast precisely in this area......  It begins to look as if he was very perceptive.

 The Giant Erratic at Freshwater Gut.  This photo was taken over 50 years ago, possibly by Nick Stephens.  The erratic appears not to have moved at all........

 These are the Saunton cliffs -- with a very jagged wave-cut platform and lots of cliff-fall debris close to HWM.  Excellent territory for erratic hunting........

In the "Cliffs of Saunton" booklet there is a double-page spread showing the distribution and lithology of 21 of the largest erratics on the Croyde - Saunton coast, based on the work of Paul and Rosemary Madgett.  All of those erratics are in excess of 50 cms on their longest axis -- ie they are very heavy to move, and highly unlikely to have originated as ship's ballast.

List (with locations) of the 21 largest erratics in the area.  Identified by Paul Madgett and published in "The Cliffs of Saunton" by Peter Keene and Chris Cornford.  (Keene, P. and Cornford, C.  1995.  The Cliffs of Saunton. 9780948444241.  44pp.  £2.95.)  For further detail, please buy the book here:

http://www.thematic-trails.org/exmoor-coast.htm

If you have difficulties in reading this, click to enlarge.

Paul and Rosemary (in their 1987 paper) have a listing of 37 boulders in excess of 25cm on the longest axis.  Please note that the numbering is different in each list. Since 1987 several more have been found, which aren't in the literature.

From Paul's notes:


The 1987 paper lists the 8 which had been noted up until that date (including the Ramson Cliff epidiorite), plus a metre-sized Contorted Gneiss that we had discovered hidden in a deep gully, almost spherical in shape - but Peter independently spotted this one and published in 1986 (I think he was alerted by Peter Robinson, who used to live in Braunton, who spotted it while doing an OU project). However, of those 8, Taylor's Dolerite (1956, one of two designated 5b by him) has disappeared long ago. It was a small slab, 29x13.5cm, in a small cave, and was moved at most spring high tides when big waves were running. I suspect it may have been broken up, possibly not helped by that cave being used by local lads & lasses as a "rave cave" at times! Taylor's other 5b, an Agglomerate, is still there, though moved intermittently within the cave.

I didn't list the extra ones referred to by Stephens in various papers, as I discovered these were either small pebbles or small cobbles, or were mistaken identifications confused with Taylor's 1956 Grey Spilite and Hughes' 1887 Quartz Porphyry (Taylor himself in his 1958 paper seems to have caused this confusion - see paper for discussion).

ASnother point is that the low cliffs of "head" immediately south of the stream on Croyde Beach (themselves simply the distal edge of the solifluction terrace around Saunton Down) have yielded to me a few small erratics - e.g. another tuff, and a porphyritic basalt. Thus while such erratics are far outnumbered by the purely local clasts in the Head, they are present. This may well have caused Stephens to assert that there are exposures of in situ till in the low cliffs of Croyde Bay; whereas I would tend to the conclusion that the soliflucted debris includes some re-worked glacially derived material.

Those thin sections are available for further study if Rob and Richard would like to see them. They include several "rhyolite" and "tuff" specimens. However, the numbering on them refers to yet another listing of mine, going back 30-odd years, which included some quite small cobbles. Thus I will need to do a bit of "archaeological excavation" in my study in order to hunt out the relevant listing and cross-reference the numbering schemes!

One rock-type that is quite well-represented in the Down End erratic suite is a Quartz Conglomerate, which I am pretty sure is from the ORS - and of course this conglomerate outcrops in South Pembrokeshire........?  There may well be other sedimentary rock-types which should be included in the erratic suite, but it is the igneous and metamorphic ones which are much more recognisably "foreign" to the area.

We also have to take into account that in the past small ships in ballast have foundered in the area - the list of wrecks in the Barnstaple/Bideford Bay area is very long. One rock-type represented on the south side of Croyde Bay by a spread of irregularly shaped cobbles, with only minor rounding of the corners, is a micro-granite showing granophyric texture - I suspect it might have been from Penmaenmawr, either simply ballast or possibly to be sold as road-stone once unloaded.

Smaller pebbles include a lot of porphyries and tourmalinised rocks, which quite possibly came down the Taw-Torridge (ice-rafted in melt-water?) from the Dartmoor area. However, I don't recall any substantially-sized cobbles and boulders of these lithologies, though there are some larger granites which might just be Dartmoor. The presence of two broken granite rollers of agricultural provenance (one on the Baggy foreshore, one along the base of the Saunton cliffs) makes me suspect that some at least of the granite cobbles originated from this kind of source!

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BSJ comment:

What's very interesting in all of this is the mention of dolerites, rhyolites and lavas in this erratic suite.  Where do such things occur in abundance?  Well, in the Fishguard Volcanic Series, for a start......
It looks as if some thin-section work on all of these samples might be rather rewarding -- whether or not there is any link with Pembrokeshire.

The Erratics at Baggy Point, Croyde and Saunton (1)

The "high level" epidiorite erratic on Ramson Cliff (photo: Paul Madgett).  In the background we can see Woolacombe Sands.

 The "fifty tonner" at Freshwater Gut (photo: Paul Madgett).

I have just been in correspondence with Paul Madgett, a geologist who has a great knowledge of the erratics in the area around Baggy Point, Croyde and Saunton. This work is given contemporary relevance by the recent discoveries on Lundy Island (which lies straight out to sea, less than 25 km to the west.)

The information he has sent me is so fascinating that it's worth reproducing here in slightly edited form. This is the first of two posts -- and who knows? There may be more, once we get going......

THE RAMSON CLIFF ERRATIC (THE "HIGH ERRATIC" ON BAGGY POINT)

 

The "erratic high on Baggy" was actually first noted by my wife Rosemary. She was doing her degree geological mapping exercise in the Croyde-Braunton area, and I accompanied her, back in 1969. She already knew of the 50-tonner, the Saunton Red Granite, and one known to her mother as "The White Rabbit" on the Down End foreshore, but this one seemed to be "new to science". Its location was such that it wasn't visible from the coast path, and a stone wall along the southern side of the field meant it wasn't visible from the south either. Prior to the building of that wall it would probably have been visible from a distance, though not particularly prominent. In 1969 this boulder was in the middle of a pasture field, right on the crest-line of Baggy Point above Ramson Cliff, though in a low-point of that crest-line. It was standing upright, part-buried in the thin soil. It was patently being used as a rubbing post by the local sheep and cattle at the time - you will see in that article a speculation about a "bull-stone" - that was pure guesswork! - and based on having heard my grandmother, daughter of a South Norfolk farmer, talking about such things in my youth. My mother-in-law, whose 19th century ancestors had farmed part of Baggy, talked with the relevant farmer, and when asked why he hadn't moved the boulder, he said it had "always been there, and he didn't like to tamper with things", or words to that effect. However, in the early 1970s this same farmer decided to plough those fields, initially simply resulting in the boulder being dislodged and lying prone; then shortly afterwards he dragged it to the edge of the field, where it has been ever since, adjacent to the Coast Path, though often obscured by gorse bushes. Subsequently the National Trust acquired these fields and cliffs, and after my early retirement from a lecturing post in London we moved permanently to Braunton, and did seasonal work for the NT, based at the Baggy car-park. Thus I had permission to every now and then go along with secateurs to remove excess gorse - it's probably time for me to do this again! - and as Ro said yesterday that she hadn't been for a walk around the "Back of Baggy" for years, perhaps we should do that tomorrow!

Some have suggested that this erratic (in its 1969 context) represents a prehistoric Standing Stone - quite feasible, and there is another standing stone nearer to Putsborough, though that one is a local slabby sandstone. Because of the occurrence of erratic boulders on the southern shore of Baggy, at Saunton Down End, and under Saunton cliffs, it was then suggested that the boulder might have been dragged up from such a location. Against this is the shape of the boulder - which is rather angular and rough-surfaced - not at all like those on the foreshore, where wave action has resulted in smooth surfaces and a fair degree of rounding of corners. Also other standing stones in the area, all local lithologies to my knowledge, are angular, with no evidence of having ever been subjected to wave action. My personal feeling is that the boulder was already lying there, and was simply pulled up into a more vertical position, at an unknown date.

While not marked on any OS maps as a Standing Stone (there seem to be quite a few in North Devon "missed" by the early surveyors), it is suggestive (to me) that there is an old map, original in the Incledon-Webber archives at the North Devon Record Office, reproduced in "Early Devon Maps" by Ravenhill & Rowe, 2000, pp 52-53), which shows "Cride Beacon" in roughly the location of this boulder. Speculation again on my part - but could the boulder have at one time served to locate the beacon fire for its probably infrequent usage?

OTHER "HIGH" ERRATICS

 

That boulder is not the only "high-level erratic" on Baggy Point I know of two others, though smaller - both now on top of the stone wall to the south of Croyde Hoe Farm, and adjacent to the higher footpath/track along the south side of Baggy. Can supply images, if required. Both are tuffs/agglomerates; one a grey almost square block, the other smaller, more irregularly shaped, of a pinkish tinge. Neither were there in the 1970s, and seem to have appeared in the late 1980s or early 1990s. Formerly Croyde Hoe Farm had been mainly arable, and the fields produced regular "crops" of flint tools and waste flakes. In 1969 the farmer, a Mr Bagster, had shown us his collection after we asked permission to walk over his land, and subsequently one of his workmen has allowed me to photograph samples from his personal collection, mostly Mesolithic, but including Neolithic, Bronze Age artefacts, and even a squared-off flint from a flint-lock rifle, all found on Baggy. In the 1990s the new National Trust tenant farmer went over entirely to sheep, so the fields are ploughed only rarely nowadays.

Thus my guess is that the former farmer, knowing of the interest in his land by geologists, and recognising these cobbles / small boulders as "different", having ploughed them up, then placed them in a prominent position for others to see. Neither have the appearance of ex-beach boulders, and I would suggest that they represent the residuum of a former cover of till, now virtually all eroded, most of the boulders once emplaced higher on the coastal landscape now being incorporated into beach deposits, some incorporated in the base of the Raised Beach, as with the Saunton Red Granite (hence any putative glaciation to emplace the boulders needing to be pre-Ipswichian).

LOW-LEVEL ERRATICS

 

In 1981 my mother-in-law, Ann Inglis, spotted a large boulder at the back of Croyde beach, where wave erosion had eroded the dune front. I was called from my then-home in Leighton Buzzard, and found the boulder was a tuff / agglomerate - roughly the same size as the Ramson Cliff erratic, and again angular rather than well-rounded like other shore-line erratics. It was in a novel stratigraphic position, partly buried in the upper surface of the Head, that in turn buried under peaty clays and silts in this locality (immediately north of where the stream cuts through the dunes onto the beach). Subsequently the beach-owner dragged this boulder into the stream-bed, so that its context was lost, and Ann arranged with the local coastguard for it to be moved to the garden of her holiday home in Croyde (now ours) where it still resides.

Because this needed recording in the literature, but need putting in the context of other known erratics in the area, I conducted a literature search, and found that very few of the erratic boulders that we knew of were in fact recorded. At the time, though based in London, living at Leighton Buzzard, we had regular family holidays in Croyde - and both son and daughter were "roped in" to help record these boulders - and to find more. In fact they soon turned this into a game with prizes - a stick of Croyde Rock for every "new" erratic boulder with max dimension greater than 50cm (later scaled down to 25cm by my daughter, keen to get as many sticks of rock as possible!) Amazing how rapidly a 9 & 7 yr old become efficient erratic-spotters if the incentive is there!

Family and work commitments delayed publication, but eventually a paper was published in the Transactions of the Devonshire Association, 1987: "A Re-Appraisal of the Erratic Suite of the Saunton and Croyde Areas, North Devon", P A Madgett & E A Inglis; vol.119, pp 135-144.

THIN SECTIONS

 

At the time of the discovery of the Ramson Cliff boulder I was working with John Catt at Rothamsted, and he encouraged me to have a thin section made, which the Geological Museum staff subsequently identified as an epidiorite, possibly from NW Scotland. In 1974 a short note about this erratic was published in the Quaternary Newsletter No.14. Somewhere I will still have the thin section, and could loan you this, if you are interested in following up the lithology - it would be interesting to know whether it bears any resemblance to any of the Presceli "bluestones"!

During the early 1980s I had several more thin-sections made of the Croyde - Saunton erratics. Peter Keene borrowed some of these, when he had a researcher from North America visiting Oxford Brookes; his comment on the 50-tonner was that while it might well originate from NW Scotland, the lithology also fitted granulite gneiss from Greenland, and speculated that ice-floes could have carried it from there across the Atlantic at a time when the ocean current circulation was different to that of today. That be as it may, there are many and varied far-travelled erratics along this coastline, yet there still seems to be a reluctance among geologists to grant more than grounded ice-flows for their emplacement.

The Lundy glacial evidence (referred to in your blog last week) would support the idea of Baggy - and indeed much of the coastal fringe of N Devon - being over-ridden by an ice-sheet at the same time. I look forward to hearing in a few years time of the results of the investigations hopefully to be carried out by Phil Gibbard's and Tom Spencer's research student...


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Grateful thanks to Paul for all the above. More to come.....

The Baggy Point area.  The beach to the north is Woolacombe Sands.  The beach to the south is Saunton Sands.  The small one in the middle is Croyde Bay, and the village is Croyde.

In the meantime, here are some key references:

Peter Keene  1989 Read at the Annual Conference of the Ussher Society, January 1989
Classic landforms of the North Devon coast,  Geography Unit, Faculty of Environment, Oxford Polytechnic, Oxford, OX3 0BP.

Keene, P. 1986. Classic Landforms of the North Devon Coast. Geographical Association, Sheffield.

Keene, P. and Cornford, C.  1995.  The Cliffs of Saunton. 9780948444241.  44pp.  £2.95

Kidson, C. 1971. The Quaternary history of the coasts of South West England, with special reference to the Bristol Channel coast. In: Gregory, K.J. and Ravenhill, W. (eds) Exeter Essays in Geography, University of Exeter, 1-22.

Kidson, C. 1977. The coast of South West England. In: Kidson, C. and Tooley, M.J. (eds) The Quaternary History of the Irish sea. Seel House Press, Liverpool.

Kidson, C. and Wood, R. 1974. The Pleistocene stratigraphy of Barnstaple Bay. Proceedings of the Geologists' Association, 85, 223-237.

Madgett, P.A. and Inglis, A.E. 1987. A re-appraisal of the erratic suite of the Saunton and Croyde Areas, North Devon. Transactions of the Devonshire Association, 119, 135-144.

Madgett, P.A. and Madgett, R.A. 1974. A giant erratic on Baggy Point, North Devon. Quaternary Newsletter, 14, 1-2.

Pengelly, W. 1867. The raised beaches in Barnstaple Bay, North Devon. Transactions of the Devonshire Association, 1, 43-56.

Pengelly, J. 1892. The granite boulder on the shore of Barnstaple Bay, North Devon. Transactions of the Devonshire Association, 6, 211-222.

Stephens, N. 1966. Some Pleistocene deposits in North Devon. Biuletyn Peryglacjalny, 15, 103-114.

Stephens, N. 1970. The West Country. In: Lewis, C.A. (ed) The glaciation of Wales and adjoining regions. Longmans, London, 267-314.

Stephens, N. 1974. North Devon. In: Straw, A. (ed) QRA Easter Meeting Field Handbook, Exeter.

Taylor, C.W. 1956. Erratics of the Saunton and Fremington area. Transactions of the Devonshire Association, 88, 52-64.

Taylor, C.W. 1958. Some supplementary notes on Saunton erratics. Transactions of the Devonshire Association, 90, 187-191.