Field trip to Caistor St Edmund quarry, 1st August 2020

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On the 1st August, UKAFH members gathered at Caistor Quarry in Caistor st Edmund, a village just south of Norwich in Norfolk. Our hosts, Needham Chalks Ltd, kindly granted us permission to visit their working quarry to study the geology and search for fossils found within the exposed rocks.  This was the first club hunt to take place since the outbreak of coronavirus and we were rewarded with a hot, sunny day as we welcomed friends old and new to our socially-distanced field trip!

The working quarry produces thousands of tonnes of ground chalk, lump chalk and flint per annum and sand derived from the Norwich Crag and Pleistocene gravels are also commercially extracted from the surface before the extraction of chalk begins. Generally the Pleistocene exposures at this location are difficult to access as we are within the steep quarry walls but in any case the chalk is the more interesting and productive when it comes to fossils.

The chalk forms part of the Beeston Chalk Member, some of the earliest chalk exposed in the UK of Late Campanian age at circa 80 million years old. Importantly, this chalk member is not exposed on the UK coastline and so access to it can only be achieved via inland sites such as Caistor Quarry. The chalk formed at the bottom of a warm, relatively deep sea that was inhabited by great numbers of microscopic coccolithophores – phytoplankton whose tiny calcite platelets, called coccoliths formed the striking white calcium carbonate sediment. Fortunately for us the Beeston Chalk Member is particularly fossiliferous, with belemnites, brachiopods, echinoids and fish remains being frequently found.

We began with a geological explanation and description of likely finds provided by Sam Caethoven, along with a health and safety briefing,  before heading into the quarry. The quarry was in operation during our visit so it was vital we kept away from the large machinery and remained as a group throughout the hunt, however the work today was focused on sand extraction so we had the entirety of the chalk pits to examine.  Since our last visit in 2017 the quarry landscape had changed significantly so we saw different exposures compared to our previous visit. There were also large piles of loose material to go through on the floor of one pit.  Certainly the number and type of finds made by the group were very different to those found on the previous occasion.

We were in many ways lucky with the weather, a beautiful warm and sunny Norfolk day, without the unrelenting heat and high temperatures experienced earlier in the week, however within the quarry we were very exposed so plenty of water and sunscreen was essential and the bright sunshine reflecting off the bright white chalk was glaring, making it harder to spot fossils than might otherwise be the case.

The finds began with a large multi-block of echinoids in flint made by Sam Caethoven.  Although the echinocorys echinoids were unextractable from the block and somewhat worn it still made an attractive piece, even if only to serve as a doorstop!

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Echinoid multi-block found by Sam Caethoven containing at least 8 specimens

On our previous visit echinoids were plentiful however on this occasion we wound them much harder to come by.  However some beautiful specimens were founds, primarily in flint blocks, by Dave Clark, Tracey Chapman and Andrew Bourke.

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Beautiful Echinocorys sp. echinoid in a flint block found by Tracey Chapman

One fossil the group found in abundance was belemnites, a squid-like cephalopod whose guard is preserved as a glossy brown bullet-shape.  Some fine examples, including complete specimens were found, with some displaying entobia, the fine, web-like traces left by the presence of boring sponges. Brachiopods and bivanves were also found.

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Brachiopod and belemnites found by Andrew Bourke

Since the quarry was dug deeper than our previous visit we were fortunate to find several examples of fish remains from the lower beds.  These appear as glassy, caramel-coloured scales preserved in the chalk.  Several members found fish scales and partial fish, with at least one find including articulated vertebrae.

It was a glorious day to be out fossiling and everyone appreciated the opportunity to spend the day doing something they loved along with like-minded people.  Lockdown has been hard on many of us and it was a great pleasure to be safely outdoors seeing friendly faces and catching up, albeit at safe distances.  Thankfully no-one wants to be fossil hunting in each others’ spaces anyway and we had a huge quarry all to ourselves to space out in. Thank you to the awesome group who attended and a huge thank you goes to Needham Chalks Ltd who let us investigate their quarry.

Gilwern Quarry, Powys

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On Sunday 3rd November, we re-visited Gilwern Quarry, Powys, to hunt for trilobites and other Ordovician goodies!

Gilwern quarry is privately-owned and is situated on the edge of the Brecon Beacons, in beautiful and isolated moorland. Gilwern is famous for its trilobites, which are generally very well preserved, and can be found in abundance. Gilwern Hill is made of Lower to Middle Ordovician volcaniclastic rock, which form part of the Builth Inlier. The site has rocks from the Llanvirn series (approximately 460 million years old) and exhibits the following beds:

·         Upper Didymographus murchisoni Shales

·         Pale flinty, tuffaceous beds

·         Main Rhyolitic tuffs, with Lower Didymographus murchisoni Shales

·         Rhyolitic tuffs and agglomerates

·         Upper Didymographus bifidus Beds

·         Lower Didymographus bifidus Beds

The site has been interpreted as a near-shore, shallow water environment, which due to the number and range of ages of Ogyginus found here, was identified as a breeding ground for the Ogyginus trilobite.

A small group of us were met by the landowner, Emma, at the on-site shepherd’s hut. Emma gave us her amazing warm welcome, with hot teas and coffees at the ready! For those of us who had travelled far, this was most welcome!

We were very lucky with the weather, as the previous week had seen torrential downpours, with part of the quarry under several feet of water. Despite this, we found a great selection of whole and partial Ogyginus and Bettonolithus trilobites.

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The beautiful view from the shepherd’s hut
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Large Ogyginus trilobite!

We would like to thank all for attending – we hope you had a fantastic day! A special thank you goes to Emma for her fabulous hospitality!

Access to the quarry and rental of the self-catering shepherd’s hut can be requested via https://www.uppergilwernquarryhut.co.uk

For further information on Gilwern fossils, please refer to    https://www.asoldasthehills.org/oath_homepage.html

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Leader selfie! (Sam, Terry and Mike)

UKAFH field trip to Folkestone Sunday 6th October 2019

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Another week another hunt! Great stuff! This week we were visiting the late Cretaceous deposits of the Gault Clay and Lower Greensands at Folkestone, Kent. The geology at Folkestone is Albian age, between 90 and 112 million years old. Although there are chalk exposures east of Folkestone, our focus today was west from the beach entrance at the Warren heading towards Copt Point.

We assembled in a quiet residential street (I think the locals have got used to our occasional assemblies of yellow jacketed, hard had wearing groups!) and Sam gave a superb talk with some great show and tell fossils. The rocks at Folkestone we’re formed in a shallow marine environment so the fossils include molluscs such as ammonites, belemnites snd bivalves as well as corals, sharks and other fish, urchins, turtle and occasional marine reptile remains. However the seasonal dryness in the locality is evidenced by scarce dinosaur footprints. Many fossils are exceptionally preserved, retaining original shell preservation, due to the soft and highly anaerobic clay which preserves aragonite and calcite shells in beautiful, iridescent colour. Chris, our leader on the day, briefed the group on the locality and a couple of health and safety messages and we headed down to the beach carefully, then heading West from the chalk to what we hoped would be much exposed clay.

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We totally beat the weather forecast, with many of us stripping off the full waterproofs for much of the excursion, and got away with only a couple of showers. Unfortunately we could not contend with the abundance of sand covering a lot of the clay so a chunk of the areas we are used to hunting were covered. This did not mean it was an unproductive hunt though and more than I was expecting was found! Yay!

The first fossils encountered were from the freshly slipped clay. The colourful shells of the bivalves within were evident but were too fragile to collect and we also found an unusual number of equally fragile heart-shaped urchins.

A very large and exceptionally well preserved shark tooth was found by Jo and Isabel and Peter Bines continued his hot streak, finding a little tooth that would have gone unfound without his persistent sieving efforts as well as part of a chimaeroid fish tooth palate which has a distinctive spotted texture and can be found in both the Gault clay and Greensand.

Suzanne, a first time guest was pleased to find some iridescent ammonite sections and see the beautiful but fragile bivalves which look gorgeous on the beach but have a short shelf life once exposed. Meanwhile Louie Fleckley found some beautiful complete ammonites!

Other finds on the day included crinoid stems, a fish vertebra, a solitary coral, many ammonites and ammonite fragments including sections of heteromorph (irregular/uncoiled) ammonites which are unusual but quite common at Folkestone and yet another great find from hawk-eyed Peter who found a beautiful small crab carapace.

Everyone had a fun time and it was absolutely lovely to wander up to Sam and hear that our youngest guest of the day Louie wanted to tell her before he went home that he had a great time and thought we were all lovely! Thanks for the great feedback and that is exactly why we do this. We love to encourage and inspire and share our love for fossils!

Roll on the next hunt!

Chris Tait

 

UKAFH field trip to Withington, near Cheltenham, Saturday 5th October 2019

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IMG_7309UKAFH hosted its largest field trip ever on Saturday 5th October when we welcomed 50 members, many of them new joiners, to privately owned ploughed farm fields near Withington which we had obtained permission from the landlord to visit. The proximity of the topsoil to the Inferior Oolite below in this locality means that ploughing brings rock to the surface which contains a large variety of fossils. A field hunt (with landlord permission) really is an excellent way to find fossils with little effort other than to look patiently and “get your eye in”. It is comparatively easy to find rocks on the surface of the topsoil and inspect them for fossils, many of which are already loose from the rock. No tools or equipment are required other than a container for your finds and, at this location, a bucket was ideal as fossils were plentiful and they are easy to carry and drop the robust fossils into as you go along.

The weather conditions were dry and overcast, making it an ideal day to fossil hunt as the rock was relatively clean and easy to spot so plenty of finds were made.

Once assembled at the farm, our guest leader and local expert for the day, Mark Baggott, gave us an introduction to the local geology and fossils. After enjoying Mark’s marvellous display of sample fossils and information sheets and his introduction to the site the group spread out to hunt across the two newly cleared fields and finds were quickly being made.  The lower field produced a good variety of abundant brachiopods, bivalves and regular echinoids and some gastropods, whereas the upper field yielded complete and partial Clypeus ploti as well as larger molluscs and a fragment of ammonite, which is unusual as ammonite finds at this location have historically been quite uncommon.  The changes in types of find was indicative of and helped demonstrate the stratigraphy of the area, with the upper field being at a higher elevation and therefore exposing younger rocks than the lower field and, therefore, younger and older fossils.

The Cotswold Escarpment rocks are almost exclusively marine and were deposited mainly in warm tropical seas. Plate tectonics has transported this part of the Earth’s crust northward over the last 150-200 million years to its current location. The Middle Jurassic rocks here are the characteristic ‘Cotswold Limestone’; soft, yellow, sandy limestone at the base of the Inferior Oolite (literally egg stone), a sedimentary rock formed from ooids, spherical grains composed of concentric layers. Towards the top of the Inferior Oolite the limestone becomes more fossiliferous and is referred to as ‘grits’ due to its coarser texture. Such an Inferior Oolite exposure is exposed at the farm and the fossils that this limestone contains date from between 167 to 175 million years ago at a time when this farm was at the bottom of a warm tropical sea. The rocks exposed near the farm comprise the Salperton and Aston Limestone and, from a fossil perspective, the most interesting layers are the Grits (Clypeus, Upper Trigonia Grit and Lower Trigonia Grit), named from the index fossils found in those rocks.

The commonest fossil found at this location is the sea urchin (echinoid) Clypeus ploti. These are more commonly known as Chedworth Buns (after the nearby village where they were often found) or Pound Stones, because their weight was usually a good approximation to 1lb. Clypeus lived in burrows on the seafloor, and burrowed their way through the sediment to get nutrients. They had fine hair-like spines and are an example of what is known as an “irregular” echinoid because they are shaped, not rounded.  Because these irregular echinoids lived in the sediment, they didn’t need the spiky and sometimes poisonous spines that the spiny sea urchins (known as regular echinoids) that we can see on the seafloor today have for protection. As well as the Clypeus Ploti we find other echinoid species which are “regular” and would have had sharp spines.  Unfortunately the spines rarely fossilize still attached, but they can frequently be found individually in the same sediment.

Trigonia bivalves gave their name to the second grit since they are very common at this horizon.  Trigonia are a family of saltwater clams, noticeable because the exterior of the shell is highly ornamented. Other fossils to be found comprise of brachiopods, bivalves and gastropods. Brachiopods are a marine animal that had hard valves (shells) on the upper and lower surfaces.  They are distinguished from bivalves which also have two valves/shells but in a left/right arrangement rather than upper and lower.

Brachiopods are bottom dwelling marine animals and, although rare today, in Jurassic times they dominated the sea floor and were frequently found in large colonies. One characteristic unique to brachiopods is the pedicle, which is a long, thin fleshy appendage which is used to burrow into the sea floor as an anchor while the brachiopod could feed clear of the silt.  Although the fleshy pedicle itself does not preserve in the fossils, the opening at the top of the animal from whence the pedicle connected (known as the foramen) is clearly visible. Brachiopods are filter feeders, gathering microscopic organisms and bits of organic matter from the water that flows by them using a specialized organ called a lophophore. This is a tube like structure with cilia (hair like projections). The cilia move food particles down the lophophore to the mouth.

Brachiopods are often known as lamp shells as the curved shell of the some classes look rather like Roman pottery lamps. There are two main groups of articulate brachiopods from the Jurassic, terebratulids and rhynchonellids. A common example of a telebratulid brachiopod found here is Stiphrothyris tumida; their main characteristics are their ovoid/circular shape, presence of a clear hinge line and a circular pedicle opening located in the beak. This brachiopod is a type example for lower Trigonia grit. The second of the main orders of articulate brachiopods is the rhynchonellids. The main characteristics are their strongly ribbed wedge shape, the absence of a clear hinge line, the line between the valves/shells is often zigzagged and a circular pedicle opening located in the beak. An example of such a brachiopod found here is Burmirhynchia sp.  The rhynchonellids were able to extrude their lophophore out of the shell in water, whereas the terebratulids maintained their lophophore within the shell.  The ability to extrude the lophophore led to more efficient food-gathering and is probably why rhynchonellids survived the mass extinction events better than the terebratulids.

Bivalves include such animals as clams, oysters, cockles, mussels, and scallops are also found at Withington. The majority are filter feeders and often they bury themselves in sediment where they can be safe from predators. Others lie on the sea floor or attach themselves to rocks or other hard surfaces, a few such as scallops are able to propel themselves through the water. The shell consists of two usually similar valves, and is joined at the hinge line by a flexible ligament with interlocking teeth on each valve. This arrangement allows the shell to be opened and closed for feeding without the two halves becoming disarticulated. Bivalves found here include Thracia (a member of the clam family) and Pleuromya (a member of the mussel family).

If we compare brachiopods and bivalves, although they resemble bivalves, brachiopods are not even molluscs.  They are so unique that they have been placed in their own phylum, Brachiopoda. Brachiopods are shelled marine organisms that superficially resembled bivalves in that they are of similar size and have a hinged shell in two parts. However, brachiopods evolved from a very different ancestral line, and the resemblance to bivalves only arose because of a similar lifestyle. The differences between the two groups are due to their separate ancestral origins. Different initial structures have been adapted to solve the same problems, a case of convergent evolution. In modern times, brachiopods are not as common as bivalves. Brachiopod shells are often made of calcium phosphate as well as calcium carbonate, whereas bivalve shells are composed entirely of calcium carbonate.

Also to be found at Withington are gastropods. They are called univalves because they build a single coiled shell to protect their soft bodies. Ancient fossilized gastropods are related to living gastropods of today and are snails. Gastropods can be carnivorous or herbivorous. Their tongue is covered with thousands of tiny teeth to tear apart food.

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A scarce partial ammonite found by Chloe

UKAFH would like to sincerely thank the landowner for allowing us access to the fields.  Special thanks also to Mark Baggott for organising the visit and providing a fantastic display of local fossils and information for us all to refer to throughout the day.  Thank you also to Mark and to Alan Banyard for bringing along some very nice examples of undamaged and prepared Clypeus ploti and ammonites from nearby locations for members to take home and to Andy Crawte and Alan Banyard who gave their time to assist our attendees in identifying their finds.

All in all we had a great day out and it was wonderful to welcome so many enthusiastic new members and see so many families enjoying what was for many of them their first fossil hunt. Everyone went away with finds and I saw many happy smiles! This is exactly what UKAFH is all about and I really hope we see many of you on future fossil hunts. Our 2020 hunt calendar has now been published so please take a look and I hope to see you all soon!

Lee-On-The-Solent 22nd September 2019

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The 22nd September will go down in history…. ok that’s an exaggeration but it will certainly be remembered by those who attended as the wettest UKAFH hunt of recent times.

Lee had some choice weather to test our resolve. I arrived early hoping to grab a cuppa and a bacon sandwich from The Shack but the owner had clearly seen the forecast and stayed home! Nicky arrived shortly after and having given her the bad news about no bacon sandwich, we donned our waterproofs and waited for people to arrive.

Once we had all assembled I gave a truncated talk in the pouring rain about the “Eocene optimal climate period” and Nicky and I showed examples of what we could expect to find. Then we headed off to the fossils, pleasingly close to the car park at this location.

The first hour hunting was spent in heavy rain and was a bit lean with the finds, although within a minute of getting to the shingle Nicky found a shark tooth that gave everyone encouragement.

We got lucky for about half an hour around low tide when the rain lifted and finds increased.

Quite a few Ray plates and shark teeth were found as well as the some nice bivalves and gastropods. Aside that there were a few different finds; Lesley found a wonderful Micraster echinoid, easily the best example I’ve seen from here.

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Nickynoid (oops did I reveal her nickname 😀) loves echinoids was very excited to see that.

Daniel Free was lucky to find a piece of turtle carapace from Emys with a rib attachment showing.

One young man had an exceptional days hunting. Peter Bines found by far the largest shark tooth of the day at over 4cm, the smallest tooth of the day and a chunk of bone I tentatively identified as alligator rib. (Corrections welcome) and a lovely shark tooth on the way back to the car park.

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It was lovely to encourage our young guests. They ran over with various pebbles for me to identify, occasionally hanging around in case there was something to find. Sometimes there was and they “found” a plate or a tooth. I loved drawing the square in the shingle and having not only Aaron but also his Dad searching. Aaron’s cool reaction when he finally found it was funny!

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The rain returned in earnest at about 12 and by then many had got wet enough. I don’t blame them at all. A few people stayed till the end and Peter was rewarded with the last nice tooth of the hunt.

Despite the weather it was a great hunt with some good finds from some enthusiastic people! Not going to lie, hope when we next go back we get luckier with the weather!

UKAFH field trip to Doniford Bay, Somerset on 15th September 2019

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IMG_6769On 15th September 21 UKAFH members set out to explore the geology and fossils of Doniford Bay in Somerset.  Our group assembled at Doniford Farm Park with their kind permission, since the nearby public car park was closed at the start of the year. This allowed us to park and gather easily as well as providing a wonderful opportunity to purchase delicious lunches and a variety of local produce and wares as well as meeting the farm animals!

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In the glorious sunshine of a late September heatwave, we walked as a group to the nearby beach access and descended to the bay.  Sam set off to check the terrain and rock exposures on the beach and Aidan, the group leader for today’s event, provided some information to the group on the geology of the area and what the group might expect to find.  Directing our gaze to the distant cliffs in the direction of Watchet, Aidan explained that the red layers which were clearly visible displayed a history of interchanging desert and aquatic conditions, with water encroaching on the landmass then retreating to give way to desert conditions.  These varying states, occurring as Pangaea broke up and the Triassic period came to an end, finally gave way to full inundation by the ocean as the Jurassic period commenced.  The change in condition brought marine life to the area which leaves its record in the rocks beneath and around us in this location.

The rocks at Doniford Bay represent the very earliest part of the Jurassic period beginning 201 million years ago.  The most abundantly evident fossil is the ammonite Psiloceras planorbis, which is a zone fossil, which means it is recognised as being the defining biological marker for the start of the Hettangian stage 201.3 ± 0.2 million years ago, the earliest stage of the Jurassic period. All ammonites with the exception of the genus Psiloceras went extinct at the end of the Triassic so all Jurassic and Cretaceous ammonites are descendants of this genus.

Aidan continued to explain that the other ammonites we were likely to see demonstrate the evolution of this ammonite as it adapted and evolved to different niches of the newly opened up marine environment following the mass extincions of the end Triassic.  Firstly we will notice Caloceras johnstoni, which, like Psiloceras planorbis is always crushed flat but maintains aragonite (mother-of-pearl) shell preservation which often demonstrates spectacular rainbow iridescence but which evolved a ribbed shell which would have afforded advantages, possibly affecting buoyancy and swim control or resistance to predation or other damage.  This was succeeded by larger and more ribbed species like Arnioceras and Coroniceras which we hoped to see in situ in the wave-cut shale platforms.

The post-extinction sea quickly refilled with new life and Aidan informed the group that alongside the abundant ammonites we could also hope to find fishes, marine reptiles such as ichthyosaurs and plesiosaurs and plant remains.

We headed off as a group towards an area of loose rocks on the foreshore where we knew ammonites could be commonly found. Aidan pointed out some examples that were clearly visible and demonstrates how best to split the fragile shales, reminding group members to be safe using goggles and ensuring others were not close and vulnerable to flying chippings. He added that the delicate ammonites benefitted from preservation to bring out their colours and prevent deterioration and shared a tip that a smear of lemon juice was often effective in helping bring out the colour. Finally Aidan reminded members that they should only collect a few examples as no-one needs many identical specimens and there should be plenty left for others.

The group dispersed over the pebbly area and were quickly finding examples of Psiloceras and some Caloceras ammonites as well as some fragments of 3D ammonite. Chris Tait found a beautifully preserved example of Brachyphyllum, a cone- bearing plant which is known from the late Carboniferous to the Cretaceous.

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Brachyphyllum specimen found by Chris Tait

After the group searched the loose foreshore pebbles Aidan took the group to the ledges of shale along the beach where we could observe the later, larger ammonites like Arnioceras and Coroniceras. The site is SSSI so hammering if in-situ rocks is mot permitted and these specimens cannot be extracted but we were all able to view, photograph and enjoy the many beautiful examples visible on the rock surfaces.

We were fortunate to observe, on close inspection, a small fossilised fish exposed in the rocks and one lucky group member found a small ichthyosaur vertebra. Also visible were crinoid ossicles and sea urchin spines.

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Fish found by Aidan Philpott
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Small ichthyosaur vertebra found by Deborah

As we returned to the slipway to leave the beach accompanied by the sound of the steam train whistles there was still a surprise yet to come – a beautiful, unusually preferved brachiopod found by Jonah.

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UKAFH would like to thank Doniford Farm Park for allowing us to park for the duration of our excursion.  Your pasties and pies make delicious lunches and we wish we could have stayed for the delicious looking carvery!

We hope everyone had an enjoyable day at Doniford and we hope to see you all again on future field trips.

UKAFH field trip to Burnham on Crouch, Essex on Sunday 7th July

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On a warm but comfortably overcast day a group of 20 UKAFH members met at the marina car park at Burnham on Crouch to study the geology and collect fossils from Butts cliff at Burnham on Crouch. Our leader for the day was Eliott Mills, who has lifelong experience of this and other London Clay locations. Eliott brought a number of superb specimens collected at Burnham on Crouch and other London Clay localities to illustrate the quality and diversity of fossil specimens to be found at this location. Fossils include over 20 species of shark tooth, crabs, lobsters, turtle, birds and fish as well as invertebrate fossils and derived fossils from the chalk such as sea urchins.

The London Clay (Eocene ~50 mya) from the Ypresian of the Eocene is well exposed at Burnham on Crouch. The beds dip westwards and there is a large amount of the sequence exposed. This is some of the oldest London Clay that is accessible.

The London Clay banks here still provide the collector with a rich assemblage of fish taxa, almost exclusively of elasmobranchs (cartilaginous fish, such as sharks, rays and skates). The tidal river cliffs and foreshore exposures reveal a section through the marine rich London Clay, Division D. The main cliff, known as ‘The Cliff’ or Butts Cliff locally, forms a 2 -3 metre thick outcrop on the north shore, which contains the fish fauna (mostly of sharks) which wash out onto the foreshore.

Large cementstone nodules from the London Clay are found here and resemble those found at Sheppey sites. However, at Burnham-on- Crouch, the concretions are largely unfossiliferous when broken open.

At the western end of Cliff Reach, the Upper Chalk is sometimes exposed on the foreshore in boulders. These can contain shells from the Maastrichtian stage of the Upper Cretaceous. This bed is directly beneath the London Clay.

After a walk if some 40 minutes the group arrived at the cliff and began searching for fossils. Many fossils are small and require careful searching through fine shingle but finds were quickly made.

Claire and Sam quickly found small shark teeth in the shingle and Jenny then found a cidarid sea urchin spine derived from the chalk. Xiang then found a bird bone, a rare and excellent find! Leon found a large and very well preserved striatolamia (sand tiger) shark tooth and Aidan found a complete ray tooth plate file.

As we continued to search the beach everyone was able to find and share examples of their finds. Many attendees were able to find small crab nodules and fragments amongst the shingle and Jack found a number of larger crab nodules at the margin where the shingle gave way to the clay which he kindly shared with group members. Steve found a fish jaw with clear tooth sockets and several fish vertebrae were also found.

The find of the day was made by Eliott, whose goal of many years was finally achieved when he found a Hexanchus (6 gilled cow shark) tooth. These tiny teeth are uncommon and many years of searching without success were finally paid for.

Finally the group began the long walk home as the tide came in. Always remember to be safe and to fossil hunt on a falling tide, along time to return safely taking account of any points along the route where there is risk of being cut off. Thank you to Eliott, Sam, Jack, Salma and Aidan, our UKAFH volunteer team for leading and supporting this event.

Hock Cliff – 30 June 2019

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On Sunday the 30th July, UKAFH embarked on a fossiling foray in Gloucestershire, on the River Severn near a small village called Frampton on Severn – a location known as Hock Cliff.

We met at a private car park for which we were very grateful to have received permission to use. (Please note that if visiting Hock Cliff individually parking would need to be sourced elsewhere along the road heading north west from Frampton on Severn). From here, group leader Lizzy Hingley guided us on a short walk through fields before arriving on the riverbank where a cliff, at most 20m tall, is exposed for a stretch of just over 1000m.

The cliff and foreshore exposed at Hock Cliff are made up of the lower portions of the Blue Lias formation, an early Jurassic formation about 200 million years old. As well as Gloucestershire, The Blue Lias formation is exposed along the Somerset Coast, in Dorset near Lyme Regis, South Wales and even parts of Yorkshire, so the material here was not unfamiliar to many of the seasoned hunters on this trip. The Blue Lias consist of repeating bands of a blueish limestone and darker shale (The name Blue Lias is derived from the blue colour of the limestone, the colour itself is derived from the high concentration of pyrite in the stone). These sediments were formed in a warm, placid, shallow sea which would have been much closer to the equator than present day. The surprisingly formulaic nature of the repetitive limestone and shale bands can be interpreted as resulting from a Milankovich Cycle. This is a cycle in which the earth wobbles on its longitudinal axis – a result of gravitational influence from other celestial masses – which result in earth’s polar regions becoming closer, then further from the sun and so effecting global climate and sea level; and consequently the sedimentation of this Jurassic sea as finer sediments travel further from their source, effecting the type of sediment produced. Amazingly we can calculate the length of this cycle and so can interpret each section of limestone and shale to represent about 90,000 years of time, which unlike more homogeneous strata allows us to visualise the passage of time throughout the formation.

This location is incredibly fossiliferous with well-preserved examples from much of the familiar early Jurassic marine forna abundant here. Most notably the bivalve Gryphaea (Often called Devil’s Toenails) can be found in quantity but are remarkably well preserved, often with both valves intact and with pronounced growth rings, allowing you to calculate its age when it died. Ammonites are also common, often small and preserved in pyrite, hints of gigantic ammonites can be spotted in the limestone ledges. There is also a crinoidal bed where, if exposed, mudstone packed full of crinoid beautifully preserved in calcite can be found. Hock cliff also has its share of vertebrates including fish, Hybodus sharks and marine reptiles such as ichthyosaurs and plesiosaurs. Further down the River Severn the pterosaur Dimorphodon was found in the Blue Lias above Aust cliff so the chance of terrestrial fauna is not unimaginable.

After a short introduction to the geology and paleaontology of the area, fossils were being found by the group almost immediately. Matilda Brewer was first in with a fantastic Promicroceras ammonite preserved in pyrite and Barry Taylor found an exceptional example of crinoid bed which was not very abundant on this trip. I think everyone found a great example of Gryphaea, some with the tube casts of creatures who made their home on the shell preserved. Rob Howe struck lucky when he found a small, fairly worn but significantly uncommon ichthyosaur vertebra. However, the star of the show was by far the exceptionally rare and beautifully preserved Hybodus shark tooth found by Tegan Watts.

We were not just lucky with our fossil finds but also lucky with the fine weather, which had cooled slightly from the 30C+ the previous day. Importantly the ground was solid – if visiting this site in winter months or after heavy rain it is important to take extra care as the solid ground becomes dangerous mud.

Hock Cliff is a Site of Special Scientific Interest (SSSI) and so the cliffs and foreshore must not be hammered or dug into. However, there are plenty of loose fossils to be collected along the foreshore.

looking down rob and paul

A big thank you to everyone who attended our hunt at Hock Cliff, it was a great day with a great group of fossil hunters! See you all again soon.

Whitehaven, 9th June 2019

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On 9th June we descended on Whitehaven beach to chance our arm at finding some fossils.

The foreshore and cliffs at Whitehaven are famed for their Silesian (Upper Carboniferous) plant remains. Many of the plant fossils that can be obtained here are of exceptional preservation and whilst the section in the cliff provides good collecting opportunities, the section of foreshore beneath exposes beds of Bolsovian age (311.7–306.5 Mya) from the Westphalian Stage and generally consists of far better fossil material.

Fossil plants found here represent a time when plant life flourished and forests were populated by giant cycad trees and ferns. A substantial river once flowed to the southwest through this environment and the Countess Sandstone, provides us with evidence of this.

There are some 30 recorded species of plant remains found at Whitehaven. The foreshore is full of fossil roots in between layers of plant material. The most common plants include AnnulariaNeuropteris and Asterophyllites, and many of these can be found in their original life positions, which makes this location extremely important.

A selection of finds is shown below. We had a lovely group, some fantastic fossils found and an excellent day in the sunshine! Thank you to everyone who attended!

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Leaders Terry and Mike! (obligatory selfie)

 

Cayton Bay, North Yorkshire, 5th May 2019

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On Sunday 5th May we met at Cayton Bay beach car park and made our way down the steep slope to the beach to see what this area could offer us!

The rocks at Cayton Bay are from the Callovian of the Jurassic and are 166 million years old. They contain bivalves such as Gryphaea, in addition to ammonites, belemnites, gastropods and occasionally, shrimps.

There was a short briefing on the beach and a look at a selection of fossils that we might find, and then we starting searching.

A selection of finds is below. Thanks to everyone who attended – we hope you enjoyed your day!

Runswick Bay, 3rd May 2019

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On Saturday 3rd May 2019 we met in Runswick Bay, North Yorkshire.

Runswick Bay is a Site of Special Scientific Interest (SSSI) and the bedrock and cliffs are protected by law from the use of hammers, although we were free to hammer at loose material on the beach. We stayed away from the cliffs and looked for fossils on the foreshore.

The early Jurassic here is represented by Pleinsbachian age rocks (190-‐195 Ma) from the Early Lias and Toarcian age (180-190 Ma) from the Late Lias. This Lower Jurassic site is in the Upper Lias of the Whitby Mudstone Formation, consisting of deposits of the Grey Shale Member, the Mulgrave Shale Member and the Alum Shale Member. The Lower Lias consists of the Cleveland Ironstone Formation, whose deposits consist of the Penny Nab Member and the Kettleness Member.

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The view of Runswick Bay from the cliffs

After a short briefing on health and safety and the likely fossils we could find, we made our way down to the beach to begin the hunt.

The fossil Gods were with Peter today as he found a bumper crop of fabulous ammonites!

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Obligatory leader selfie!

Thank you to all who came. We hope you enjoyed the day and went home with some great finds!

UKAFH field trip to Smokejacks pit, Sunday 12th May 2019

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On a comfortably warm and dry Sunday 12th May UKAFH was privileged to gain access to internationally renowned Smokejacks quarry – a large clay pit operated by Weinerberger located close to Walliswood in Surrey. The pit is famous for the near complete dinosaur specimens that have been discovered there, including Iguanodonts and the first discovery of the spinosaurid Baryonyx in 1983 by amateur fossil hunter Bill Walker. Baryonyx and many other specimens from Smokejacks can be seen in the dinosaur hall of the Natural History Museum in London.

The pit cuts through a section of the Weald Clay member of the Wealden group, dating from the Barremian stage of the Cretaceous period about 130-125 million years ago. During this period England was located in the mid-latitudes and experienced a highly variable climate of alternating searingly hot dry seasons with forest fires and baked ground and stormy wet seasons with flash floods which created lakes in a floodplain environment. The resultant ecosystem was highly diverse, supporting a vast number of aquatic and land-dwelling organisms, from tiny creatures like concostracods and multitudinous insects to large herbivores and predators like Baryonyx and Iguanodonts.

A great attraction of Smokejacks pit is the enormous diversity of fossils to be found here.  Whether specialist or generalist, there are spectacular fossils to be found if you have the patience, work ethic and eye to locate them.  There are beautifully preserved insects and the early flowering plant Bevhalstia in fine siltstones, concostracods (shrimp-like shelled creatures), abundant plant material, fish scales, teeth and death assemblages, as well as crocodile, pterosaur and dinosaur remains which can be unearthed here with a good eye and a bit of luck.

Our guides for the day were Weald Clay expert and PalAss English Wealden Fossils author Peter Austen and his wife Joyce and local Smokejacks regular Mike Webster, who has discovered a number of previously unknown insects at Smokejacks. Peter provided us with a fantastic, in depth presentation on the Weald Clay and showed us some fine examples of what could be found in the pit, as well as supplying a number of handouts describing the pit and the fossil discoveries made, illustrating the pit’s stratigraphy and providing drawn examples of some of the insect types commonly found. Peter’s roadshow introduced us to the diversity of insects for which the pit is known and covered in detail the discovery of Baryonyx and also a juvenile Iguanodont which was found together with Baryonyx teeth, suggesting predation or scavenging, which was later recognised as Mantellisaurus atherfiedensis.  Smokejacks is also known for a very rare, early flowering plant called Bevhalstia Pebja.  We also saw articulated fish death assemblages, an arthropod trackway, gastroliths (the stomach stones swallowed by dinosaurs to aid digestion), plant remains and the well-known concostracans, small shrimp-like creatures which bear superficial similarity to bivalves.

We walked as a group to the pit head, from where UKAFH leader Sam was able to point out the stratigraphical layers and indicate where people might start hunting depending on what they might hope to find.

Some attendees began by walking the slopes in search of any fossils which had been brought to the surface by recent erosion.  This is often fruitful and has yielded dinosaur bones and fish teeth and scales on previous occasions.  Others chose to work the “dinosaur” plant debris bed towards the top of the quarry; a rich seam of carbon and lignite where plants have been fossilised and which has been found to often also contain dinosaur remains. Those in pursuit of insect remains headed towards the bottom of the quarry to find and split the finely grained stones in which their remains are preserved.

Soon after our arrival; finds began to appear.  Mark Goble and Sam Caethoven returned to a small siltstone exposure in the lower part of the quarry which had proved fruitful on a previous visit and were soon finding blocks containing a very rich layer of jumbled fish bones which is overlain by insect remains. Some of the fish remains are articulated and very well preserved.  Mike Webster also began to find some fine insect specimens. Many of the group came a long to see what was coming out of the insect bed and went on to find their own insects after seeing examples of the right stone and how and where to split it.

The area of the quarry we had access to has not been worked for several months and has been well-visited over that time, with little inclement weather to erode the surfaces.  Consequently finds were less common than in the past, however no-one went home empty handed.  Those digging into the plant debris bed like Andrew Marsh found some beautifully preserved seeds and leaves and surface hunters and diggers with keen eyes like Vicky Lane found Scheenstia fish scales and teeth.  Adam Ward was rewarded for his digging efforts with the day’s only dinosaur bone find and Peter Waring did very well, finding part of a hybodont shark fin spine.

It is uncommon to have access to a working quarry where the extraordinary, fossil-filled stratigraphy of the Wealden clay can be observed and explored in a way that is impossible in a coastal cliff setting and everyone enjoyed the experience.

UKAFH would like to thank Peter and Joyce Austin, Mike Webster and Weinerberger for allowing us to visit and making the outing successful, enjoyable and informative!

Sam Caethoven

UKAFH Visit Seaford, Sussex 28th April 2019

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Searching for Echinoids

On Sunday 28th April, UKAFH ventured along the coastline of Seaford in East Sussex – a small town about 10 miles east of Brighton with towering white cliffs.

As we arrived in the carpark at Seaford Head we were grateful that storm Hannah had passed the night before, not least for the erosional effects of the storm but for the light winds, mild temperatures and intermittent sunshine that greeted us.

We began with an in depth talk about the local and surrounding geology by UKAFH leader Daniel Slidel. Exposed in the towering white cliffs of Seaford is the Upper Chalk, a Cretaceous deposit (Santonian-Campanian) about 89-83 million years old. Chalk is essentially a soft limestone formed from the tiny platelets of coccolithophores – phytoplankton that was abundant in the deep, warm sea that existed here. This striking white sediment helped preserve the creatures dwelling on the sea floor, which included bivalves, sponges, corals, bryozoan and the echinoids (sea urchins) this stretch of coastline is famous for. Within the cliffs are horizontal bands of flints which are visible as far as the horizon allows and atop, the undular pattern formed by dissolution pipes – where mildly acidic rain water has dissolved the chalk to form channels.

After a short walk from the car park we descended the concrete steps onto the beach. The abundance of fossil echinoids was immediately noted as within the exposed bedrock on the foreshore were the tell-tale circular marks of weathered echinoids in situ. Tara Scott made the first discovery with a lovely echinoid preserved in flint just meters from the steps, then Susan Harley found an exquisite Micraster echinoid in situ – we could not extract these as the bedrock here is protected as a site of special scientific interested, however we continued heading west where loose boulders gave us the opportunity to carefully extract some specimens. Leo Leclerc manged to extract a great Echinocorys and Xiang Yan extracted a fantastic Micraster, both of which with their delicately preserved calcite teste intact. It is important not to overlook the loose flint shingle either as these can contain robust but often sea word specimens such as a big Echinocorys found by Aidan Philpot and a lovely little on found by Susan Harley. Other finds on the day included small bivalves, shapely sponges, coral and bryozoan.