Thanks very much to Alan Bates who has stepped in to document our evening talks, clearly recognising that things in the blog department were slipping a bit–thanks so much Alan and if your future postings from the geological front are as well written and clear as this, you have a job for life! BlueSkyMap.com IS indeed a fascinating resource to explore, Dave Green uses it and Alan provides a paragraph at the end of his article.
The East Malvern Fault to Church Stretton
When I (i.e. Alan) started writing this I had just got home from perhaps the most challenging and fascinating talk I have heard for a very long time. The delay has been the need to digest all the information presented to us with great enthusiasm!
The speaker was Dave Green who “came across geology after getting a degree in another subject”. Since then he has been a teacher of geology for over 40 years. He was definitely in teaching mode that evening.
The talk was about how the landscape of the Welsh Marches has been profoundly affected by the behaviour of two fault systems: the Welsh Boundary Fault Zone (WBFZ) and the Malvern Fault Complex (MFC). Dave started by identifying the two systems on a map. The former is a cluster of faults running South West-North East which includes the Church Stretton fault system and probably the Neath Disturbance. The MFC runs North-South, centred on the Malvern Hills and extending from near Bristol to Kidderminster. Just a glimpse at the maps revealed that the faults were adjacent to more than their fair share of major hills…… Read the rest HERE
It’s here and it’s FREE! A new app from Brooks Design, to complement the 17 that cover the length of the GeoParkway. The new one builds on its predecessors, containing an absolute wealth of information and when you try it first time please do NOT think that you had seen it all, because I can assure you, you will not have done. The full colour, GPS located, interactive Android and Apple based app presents maps, information panels, sections, photos and much much more to allow an understanding of and glimpse into how this amazing area situated in the parish of Martley came to be.
Search for MartleyRocks in your app store.
Thank you Mike of Brooks Design, you continue to develop this unique teaching resource; a picture it is said is worth a thousand words, these apps make libraries redundant. Herefordshire and Worcestershire Earth Heritage Trust and ourselves are so very fortunate to have access to you and to these tools.
The app is a component of a much larger project “Voyages in Deep Time” :A bid is shortly to be submitted to the Heritage Lottery Fund, developed by the Herefordshire & Worcestershire Earth Heritage Trust. The crux of the project is the development of apps (for smartphones/tablets) to engage principally, but not exclusively, a younger audience in the deep time heritage of our planet, with a focus on places in the counties of Herefordshire & Worcestershire. One of those sites of course being Martley! A number of high profile organisations have kindly provided their backing and future support for the project. The aims of the project are summarised as:
Connect people, primarily young people, with the earth heritage of their surroundings and build appreciation that in the very distant past this place, their home, has been forged through many epic changes in environment, life forms and location. As a means to achieve this, the proposal is to employ mobile device apps for use in the field, in combination with downloadable learning/creative materials, to facilitate individual/group interpretation of past environments which can then be made available to all via a web hosted interactive gallery. To further stimulate interest from the younger participants an app based game will be created which challenges the players to locate evidence of the deep past, whilst pitted against the clock, each other and challenges emerging from the deep time period they are currently ‘walking over’.
Numerous young students from Chantry School were led into the great unknown by Mr Bob Allison, ageless geology teacher, on three occasions this week. School had introduced a new geology course–Geological Detectives–for year 7 (12 years ish) pupils. The aim of the field trip was to finish off the course by collecting evidence from the local geology to reconstruct the past climatic and environmental conditions. Also how the geology has an impact upon landscapes. Finally, how local geology can determine what the old buildings are made of. The groups visited the church, Scar cottage, Martley Rock, Penny Hill and The Canyon. On Monday 22nd there were 29 pupils, Tuesday 56 and Thursday 58.
Mike Brooks who created ‘apps’ for the GeoParkWay and has just released one for Martley Rock, went along to introduce the children to this new teaching resource. Given the apps’ working platform–smart phones and tablets, it was no wonder that the children were immediately able to adapt to them and gain the benefits. Mike used the time to gain useful feedback to improve his designs. The image shows a QR code that take scanners straight to the app shop. Search for MartleyRocks on your Android or Apple device.
Julie Harrald accompanied the groups on Monday and Tuesday, gathering evidence for the bid she is assembling for the “Voyages in Deep Time” project. This bid is shortly to be submitted to the Heritage Lottery Fund, developed by the Herefordshire & Worcestershire Earth Heritage Trust. The crux of the project is the development of apps (for smartphones/tablets) to engage principally, but not exclusively, a younger audience in the deep time heritage of our planet, with a focus on places in the counties of Herefordshire & Worcestershire. One of those sites of course being Martley! A number of high profile organisations have kindly provided their backing and future support for the project. The aims of the project are summarised as:
Connect people, primarily young people, with the earth heritage of their surroundings and build appreciation that in the very distant past this place, their home, has been forged through many epic changes in environment, life forms and location. As a means to achieve this, the proposal is to employ mobile device apps for use in the field, in combination with downloadable learning/creative materials, to facilitate individual/group interpretation of past environments which can then be made available to all via a web hosted interactive gallery. To further stimulate interest from the younger participants an app based game will be created which challenges the players to locate evidence of the deep past, whilst pitted against the clock, each other and challenges emerging from the deep time period they are currently ‘walking over’.
Checking out stone types in the graveyard
Checking out stone types in the graveyard
Time to gather below the Church to hear Mr Allison
Mr Allison pointing out features on teh stones such as erosion, bedding planes, grain size
Scar Cottage teach in
The group leaving Scar Cottage
Matley Rock gathering
Listening to Mr Brooks describing the Martley Rock app
A 4 (ish) mile walk with a geology theme, a new trail guide with map, a short quiz and a beer named after our show site, Martley Rock, what’s not to like?
32 turned up from 10am at The Crown Martley on Sunday 21st, Fathers’ Day, some took refreshment there, then via the Nubbins and Martley Rock, following our signs placed out for the occasion, rambled up to the Admiral Rodney. More refreshment and now, following the Worcestershire Way, that has a bit of sting in its tail by way of the ascent through Nipple Coppice, onwards and finally downwards to The Talbot. Here their festival was in full swing and Martley Rock beer in bottle and on tap. Even more refreshments were partaken of.
Thanks are due to Andy who staffed the Rodney, and was probably a little more intelligible in the earlier hours, and Dave at the Talbot, unable to drink too much because he and me operated a driver’s return taxi service to the Crown. Of course a big thank you to Chris the Brewer at the Talbot for developing the beer which sold extremely well, hope he kept the recipe.
This was another first for TVGS following our successful members evening in June, and the compliments received suggest it could be repeated, possibly not on the same weekend as Wichenford Open gardens or even Father’s Day. We’ll see. The amount spent in the 3 pubs was I think quite impressive–around £350/400–lunches, drinks, snacks so it was worth while for them in some small way we hope. It was free at the point of entry ie. TVGS did not charge
HERE is a link to the Events page which itself has links to the map and guide and the quiz
Martley Rock beer and the Evening News cutting on display in Central Stores
Martley Rock bottles with their top quality labels containing Geology Information
Gary, Angus and Owen Sweeney make it to The Talbot
The first members’ evening that we have held and it was a success, so will repeat. Relaxed atmosphere, smorgasbord of topics, short, illustrated presentations and free, yes free, cheese, crisps, biscuits and a glass of wine.
First we heard from David, Ingrid and John a totally non-technical account of their recent visit to Arouca, a geopark in northern Portugal, where good contacts with the geopark team were made and some of the exceptionally well presented sites visited. Arouca with substantial European and regional Portuguese funding is developing an envied park, conserving and celebrating local geology and with it amplifying trades and crafts that would otherwise probably die out. Similar but on a larger scale to our plans for the Teme Valley. Bordering communities eye the project and make noises as to how they can join in but we understood that this is not really part of Arouca’s plan. Famous firstly for the giant trilobite fossils mentioned in Prof. Richard Fortey’s book, ‘Survivors’, of equal international status is the small area of nodular granite–known in Portuguese as the rocks that give birth (Pedras Parideiras). The process of their formation is not really understood, but basically within a matrix of granite in an area no larger than 1 square kilometre, many millions of black ellipsoid nodules are to be found. Owing, it is believed, to the differential expansion of the light coloured granite and the dark nodules, the ellipsoids gradually release from the parent rock and appear loose on the surface. One can only imagine the mystery of this in the minds of a rural and uneducated populace. The general bedrock of the Arouca Geopark is granite along with Ordovician Slates but on THIS site there is a much more detailed description. The countryside is rugged, provides excellent walking on well marked trails and abounds in drifts of colourful wild flowers.
During our stay, David had one or two personal adventures that left Ingrid and me scratching our heads. The more costly was the loss of his wallet with credit cards, driving licence and around £90. Tracing it in English by telephone to Portugal was tricky. Its ultimate fate, destruction at the hands of those who serve us–i.e. the British Consul and team, convinced us once again that the expectation of help from our overseas officers is a triumph of hope over experience. Pictures (on external site, click down arrow on right and select slideshow)
Second up were free cheeses and bikkies plus a glass or two of wine and time to look at small displays set up by Georgia with her wonderful textiles and books, Arouca with maps, books and rocks and such colourful minerals from Margaret–thanks all.
Ian (Fairchild) related the tale of fairly intrepid exploration into one of the dingles in the Teme valley at Stanford. A good friend Robin Dean (churchwarden of St Marys Stanford) owns around 20 acres of what is now VERY rough ground but was, in the old days, an orchard (it seems). Robin should really get his mower out.
The challenge in pouring rain, was to walk up the bed of Fall Dingle to one of its waterfalls, checking out rocks and plants on the way. Bits of tufa had been seen and Bishops Frome too, as well as substantial blocks of Raglan Sandstone and softer mudstone, chiselled out by the stream, innocent enough on the day but fearful in flood judging by the massive trees lodged in the bed. En-route we noticed seepages building tufa on the banks of the stream, clear indication that the limey nodules of the Bishops Frome (aka Psammosteus) limestone top member of the Silurian (Raglan) were close by but higher up the hill. A previous blog told of the lime kiln built into the limestone not far from the stream that we were exploring. Half an hour of clambering brought us to a surprising and impressive cleft with water tumbling over its lip in a double drop and a fine tufa fan encased in liverwort descending its face. So rugged the ground and obscured by trees and dense vegetation that surely few reach this spot. A much more direct route back through carpets of wild garlic, to the warmth and hospitality of Robin and Lesley’s house, rounded off a memorable morning. Thanks to Robin and Lesley for their as always warm welcome.
Surely a highlight of the evening and a marker for years to come were the three rock sample display cabinets designed and made by member Ian Pennell (of Scar Cottage the magnificent Bromsgrove Sandstone quarry garden in the village). Since retiring, Ian has submerged himself in a number of practical pursuits and his cabinet making talents were harnessed to produce these very fine items from Yellowwood, a hard, much sought after South African pine. A little ceremony of unveiling took place with a short speech of thanks from David and a round of applause. Well done and thanks Ian! A day out is set for July 11th 10am at Crown Martley–come along if you can. The ideas is to plan a route, then go out to collect, ultimately, samples of all of the formations from the surrounding area. Last count suggested there are over 20, so doubt the job will be done in one go.
Georgia, with her very obvious affection for the Lizard in South Western Cornwall, so fond is she that she had written a song that she performed for us accompanied on her guitar–yet another talent of this talented lady! Georgia knows the Lizard as well as anyone, particularly the exceptionally varied and in places very rare geology, a slice through a section of ocean crust, including the upper level of the mantle, thrust onto continental crust. One immediately realises that a field trip-would have to be at least for a weekend–and beckons strongly, a fascinating area with Georgia as number 1 choice for leader and guide.
What a day! What a day fortune bestowed (that is the word) on us for the S Wales Geological Society’s visit to Martley, one of five set up when Ian and I attended the GA annual meeting in November last. As I write it does not look so good for the visit of Reading GS today, 19th April.
Worcestershire’s countryside shone in all its glory, ploughed and harrowed fields lay cropless at this time showing off the true colours of underlying strata, undergrowth just awakening, exposures easily viewable.
SWGS bought along 13 members, none of whom needed my simple introduction to the geology of the region, so using an experienced teacher’s trick I talked about other things. We made our way to Martley Rock, then across Kingswood Lane, along the valley edge: the change in the colour of the dry, tilled earth in the fields to our right, from Triassic red to Silurian grey, was distinct under the clear blue sky.
On top of Rodge Hill
Over the B4204 past the Tee and up on to the ridge formed of upended, even over turned Aymestry limestone, above Pudford, glorious, Hay Bluff peeping over Bromyard Plateau, Brown and Titterstone Clee to the north west, valley of the Teme gorgeously spread below. Lunch at the PONS seat, only one lunch mind, not like the Ramblers 9 mile foray a couple of weeks ago where Mike and I counted three.
Off the ridge to Lower House Quarry, Crinoid City to us,
Lower House
but under intense gaze isn’t that a fault face, aren’t those slickensides and not only crinoids but cephalopods too.
Orthocone (Cephalopod) at Lower House
From Lower House towards Woodbury
Old Faces near The Canyon
Down into the dip, old quarries on all sides and into dense woodland, past
crags we worked on last week, see previous post, to the Canyon.
The Canyon
Thick layer of bentonite squeezed by cascade folds, maybe this ancient access way into the quarry was forged
along an old fault line.
Continuing along the forest path, up the Stairway to Heaven, around Penny Hill and into the quarry proper, discovering fossils at the famous face (Observer’s Book of Geology from the 50s, picture of this, captioned Martley, Wilts(!)).
Upside Down Corals (50p IS the right way up)
My non geological colleague Colin found a striking example of the upside-downness of the formations hereabouts–a large piece of coral definitely growing towards the light but here at an angle of +-45 degrees down (see photo).
My constant mantra to the group, fascinated and intent as they were by each new exposure was that we were saving the best till last. This encouraged a steady pace
Analysing Calcite Veins at Scar Cottage
towards Martley and the pub with the last geological site being Scar Cottage and its incomparable quarry garden. There certainly were a few wows and blimeys when the group rounded the corner and took in the view. Here again the experts in the group came up trumps, seeing clear fault zones with fault debris between, proving with an acid bottle, the white veins were calcite.
At Scar Cottage
Back at the pub, drinks and yes, SWGS were made to walk through the TVGS shop (just as National Trust) and indeed purchased two of our geology audits–thanks!! We hope to see you at our symposium in October geo-symposium.eu.
Thursday 16th April, Mike, Alan and I set off to Callow Farm Drive to clear away a major tree fall across the right of way near the Canyon then turned our attention to some imposing (for Martley) rock faces at the very north end of the outcrop before Callow Drive. We asked the landowner previously for access (Mr Trevor Nott) and this was kindly given, so we set about clearing away thick lianas, ivy and tree saplings. There is more to do but the three faces here are quite impressive and a great addition to our sites to look at. The bentonite is to be clearly seen running through. More work is needed but at least we made a good start.
March 23rd–Smith’s birthday and the BBC announces that major map has been rediscovered (and actually by now restored so obviously this news has been kept under wraps for some months) From the BBC (hopefully with permission) here is their article and HERE is a link
William Smith: Seminal geology map re-discovered
By Jonathan AmosScience Correspondent
9 hours ago
From the sectionScience & Environment
A first edition copy of one of the most significant maps in the history of science has been re-discovered in time for an important anniversary.
William Smith’s 1815 depiction of the geology of England, Wales and part of Scotland is a seminal piece of work.
The first map of its kind produced anywhere in the world, only about 70 copies are thought to exist today.
Now, The Geological Society has turned up another in its own archives, ready to celebrate the map’s bicentenary.
Tucked away in a leather sleeve case, the mislaid artefact was last seen roughly 40 or 50 years ago.
“It just wasn’t where people expected it to be,” said John Henry, the chairman of The Geological Society’s History of Geology Group.
“I guess the person who put it away knew where it was, but then they left and that was it – it became lost,” he told BBC News.
The archivists knew of the map’s existence – they just could not find it
In one sense, the map is better for its abeyance because it means it has not been exposed to light, and that has protected its exquisite colours.
Smith spent the better part of 15 years collecting the information needed to compile the map.
It is said he covered about 10,000 miles a year on foot, on horse and in carriage, cataloguing the locations of all the formations that make up the geology of the three home nations.
An estimated 370 copies were produced. The outline of the geography and the strata were printed from copper plate engravings, but the detail was finished by hand with water colours.
The lower edge of a formation is saturated and then the paint is made to fade back to the high edge.
It is this colouring technique, combined with the tendency of many of England’s rocks to dip to the south or southeast, that gives Smith’s map its iconic look.
Exquisite work: The maps were finished by hand using waters colours
The re-discovered copy comes in 15 separate sheets. These have no serial numbers on them, but that in itself is a clue to the map’s position in the production sequence.
The first batch in the run is known not to have carried any numbering. Another clue is the geology of the Isle of Wight. Smith changed its depiction several times, and the re-discovered map displays his earliest efforts.
The artefact is certainly among the first 50 to come off the production line, and very probably among the first 10.
Quite what its value is – that is difficult to say. Possibly in the six figures.
The depiction of the Isle of Wight is a clue that the re-discovered map was in the early production run
The Geological Society has had the map fully restored and digitised. And from Monday, anyone will be able to view it online. The paper version will also go on display at the society’s Burlington House HQ in London’s Piccadilly.
William Smith (1769-1839) is often referred to as the “Father of English Geology” – a title bestowed on him by The Geological Society, which at first had been reluctant to embrace his vision.
The organisation’s first members were drawn from the metropolitan elite, and they took a rather disdainful view of the blacksmith’s son turned surveyor.
But the big landowners knew his worth. They brought Smith in to help them maximise the worth of their estates – to drain land, to improve the soil, to find building stone, and, above all, to find coal.
The Geological Society of London was at first disdainful towards the West Country surveyor
It is this work that would have brought him into contact with the rocks and with the fossils that would lead him to his greatest scientific contribution.
John Henry explained: “The concept which enabled him to do the mapping and that drove him along almost obsessively was this realisation that specific fossils were unique to a specific stratum, and that you knew where you were in a sequence if you could see what the fossils were. That was the breakthrough. People had been collecting them for a long time and naming them in the Linnaean way, but without any real idea that they were in a sequence. But Smith knew it.”
Today, it is called the “principle of faunal succession”, and this idea holds that because fossils succeed one another in order, rocks containing similar fossils are similar in age.
This principle has enabled scientists to construct the geological timescale by which the relative ages of rocks can be measured, and thereby understand the history of the Earth.
No wonder Simon Winchester called his 2001 book about William Smith, The Map that Changed the World.
Monday, 23 March, is Smith’s birth date.
Sir David Attenborough is going to unveil a plaque at Smith’s former residence at 15 Buckingham Street on London’s Embankment.
The roughly 1.8m by 2.5m map is made up of 15 sheets
Thanks to TVGS correspondents Kim and Owain Bell for their account of the annual Herdman Lectures.
The Herdman Society is the undergraduate society of the Earth and Ocean Sciences Department at Liverpool University; William Herdman was founder and benefactor for the original Department of Geology. Each year the undergraduates organise a day of lectures at the University and we have attended these for five years. This year, as we headed expectantly into the auditorium for the first lecture, who should we see but Alasdair and Janet Maxwell Stewart!
Lectures cover topics at the cutting edge of Geoscience with reference to Biology, Astronomy, Classical Civilisation and the Media.
This year the students and their staff mentor Jim Marshall, had arranged an excellent galaxy of speakers.
First we were treated to an exuberant and enthusiastic presentation by Prof. Sanjeev Gupta (Imperial). Sanjeev is a Participating Scientist and Long Term Science Planner on NASA’s Mars Science Laboratory ‘Curiosity’ Rover mission (quite a job title!). He showed us fabulous pictures of the Martian landscape with conglomerates–evidence for the presence of water albeit aeons ago–cross-lamination and mountainous hillsides. Will they find signs of ancient life? Are microbes at the heart of the current methane fluxes? If you haven’t already taken a look at the photos and learned about the science, follow the project HERE
Dr. Juliet Biggs (Bristol) took up the challenge of following on from Sanjeev treating us to an insight into the use of ‘InSAR’ remote satellite monitoring of volcanoes to assess risk…an opportunity to increase the number of high risk volcanoes being monitored. We were delighted to recognise the map of Kilauea’s current eruption which we had studied with Thomas Jones at our January meeting!
The third speaker was Prof. Andrew Aplin (Durham) who said that after many years of quiet study of unconventional hydrocarbons his field is now ‘flavour of the month’! He outlined the gap in UK energy supply and demand and gave an even-handed evaluation of the likely usefulness of the U.K.’s shale gas resources and its possible environmental impacts.
Dr Karen Bacon (Leeds), standing in at the last minute, had the graveyard slot following lunch. She kept us well awake though informing us about how observed changes in plant physiognomy are used as indicators of historic and current atmospheric constituency and climate change.
We were all transfixed by Dr Esther Sumner’s (Southampton) brilliantly delivered exposition of her work with ‘Turbidity Currents’ including experiments to quantify their composition. These are currents under the sea that transport materials sometimes for many miles, often at great velocity and in turn this can seriously affect underground cables, shipping lanes and so on, so an understanding of them is critical and fairly new science. Who would believe this topic could be so absorbing!
Finally well-known Prof. Iain Stewart (Plymouth) who brilliantly identified the target audience he seeks to reach via television and also the web. He ably parried questions about fellow TV scientific ‘star’ Brian Cox!
The 300+ audience of A-level and university students, staff and society members such as ourselves, had been treated to a wonderfully stimulating day. Plans started on the morrow for next year’s symposium and we two eagerly await the opportunity to be there!
On Thursday February 14th, having opened all our cards and under grey skies, Ian, Mike and self, continued our foray into the Teme Valley and you know, sounds daft, but it really does feel like exploration when for us, checking out the rocks is a novel experience. Anyway, we headed first to St Marys, Stanford, to see if we could find on the ground evidence of the mapped Raglan Sandstones in the land above the church. At the spot under a spreading chestnut tree we did indeed find sandstone rocks but these were scattered about and could possibly have been from local building works although at the time we preferred not to see them that way. To us they seemed similar to the church and to local walls of the old rectory just across the road.
Sandstone from West of St Mary’s
Sandstone from West of St Mary’s
Travelling up the road by car, we entered Busk Coppice to show Mike the large quarry found on our last visit—did this supply the stone to St Marys’ Stanford, but where is the lime kiln that Mr Churchill the farmer had told us about?
Lime Kiln in Busk Coppice
Lime Kiln Busk Coppice
We wandered about down into gullies keeping in mind that it would not be far from the Bishops Frome layer, here underlying the quarried rock, St Maughans sandstone. We gave up and called the farmer who directed us back up the track to a shooting platform and
Conical Kiln in the Undergrowth
Sketch of Lime Kiln, Busk Coppice
goodness, there, not 3 metres from the trail, was a deep conical brick lined pit, a danger to anyone not seeing it, set in a levelled off terrace. On the terrace below was a substantial brick built arched construction leading into the terrace and under the cone. A magnificent example of an ancient kiln, a little the worse for wear and needing attention to remove trees and soil but other than that looked like it could be relit straight away. This would have been used to make lime for mortar for building and for the fields and was slap bang into the Bishops Frome limestone, the calcrete (fossilised soil) referred to in other posts. According to Mr Churchill, a farm worker by the name of Tommy Tucker used to live in the arched kiln. A little archaeological investigation sounds in order. Read Nils Wilkes fascinating study of Lime Kilns in Worcestershire HERE
So you burn limestone at 900C thus converting it from Calcium Carbonate to Quicklime and Carbon Dioxide, then you slake it with water making Calcium Hydroxide, known as lime putty, used as the base for a slow setting, traditional mortar still used in renovation work today.
That accomplished we went by car along the charming, twisty, switchback lane to just beyond Orleton until we reached the foot of Quarry Hill—the clue being in the name.
Valley Geological Map from BGS, click to enlarge
This is an outlier from the main escarpment. The geological maps show the limestone outcropping around the whole of the Bromyard plateau, with an island of it on top of Quarry Hill.
According to the maps the limestone was set in a sea of (Silurian) Raglan Mudstone only, and as we struggled up the wooded precipitous hillside littered with fallen trees, the redness of the soil seemed to indicate that this was the case. There were occasional obvious trackways contouring the slopes, signs of forestry work or perhaps quarrying, who knows? In the red roots of fallen trees we searched for stone as tell-tale of underlying rock and these at first were typical of Raglan sandstone. Continuing to force our way upwards to the very top we discovered a substantial area clearly shaped by human endeavour. There were no rock faces but the humps and bumps seemed to show that much of the top layer of limestone had been removed. We did uncover large stones set in a semi-circle, perhaps the foundation of a kiln?
Conglomerate, both ruddy and grey with bedrock behind
Just down the slope, we chanced upon exposed bedrock and took samples. To our surprise these mirrored an earlier finding some way down the slope (that we had tried to ignore), of a coarse conglomerate, not what we expected at all. One was ruddy, the other light grey, found 3-400mm above one another in clear layers. The map shows (Devonian) St Maughans conglomerate in a number of places, but nowhere near this spot, and certainly none below the limestone. So how to explain this? We retrieved our samples, cleaned them and will set them before the oracle as soon as we can.
