hunt
UKAFH field trip to Withington, near Cheltenham, Saturday 5th October 2019
UKAFH 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.
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.
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.
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).
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!
UKAFH field trip to Cross hands quarry, Warwickshire on 21st October 2018
We were blessed with a warm sunny day on the 21st October to Cross Hands Quarry which is located on private land owned by Mr Newman. Mr Newman had kindly created a couple of fresh spoil heaps especially for our trip, so our party had fresh pickings as will be seen below lots of fossils were found. As the trip is now centred around these spoil heaps, this location is perfect for families to visit. Therefore we had quite a few families on our trip.
The quarry was once used to supply building stone for the local town of Chipping Norton, which is located in the Cotswolds famous for its rich honey coloured stone buildings.
Cross Hands Quarry is a Site of Special Scientific Interest (SSSI) for its geological features. The rocks exposed in the quarry faces are mostly limestones, formed from the remains of shelly creatures living in the warm tropical seas which covered large areas of England in the Middle Jurassic Period, about 175 million years ago.
GEOLOGY
Cross Hands Quarry exposes rocks of Middle Jurassic age that were deposited in a shallow marine environment, not too dissimilar to that of the modern-day Bahamas. These rocks belong to the Inferior Oolite and comprise the Clypeus Grit, overlain by the Chipping Norton Limestone and the Hook Norton Limestone.
Towards the end of Upper Lias times sea levels fell somewhat, bringing a change of conditions which initiated the Middle Jurassic. Low sea levels persisted for 15 million years and in clear, warm, shallow waters the most important sediment was calcium carbonate. The accumulations of carbonate mud and carbonate sand have been transformed into a variety of limestones which are grouped into two series called the Inferior Oolite and the Great Oolite.
The word Oolite refers to a rock containing a proportion of polite. These are little spheres of calcium carbonate, typically half to one millimetre in diameter. The name comes from the Greek word on – meaning egg – because a densely oolitic limestone has the appearance of fish eggs.
The Inferior Oolite group of formations is so called not because of any inferior quality but because it’s rocks are older than, and therefore stratigraphically below, those of the Great Oolite. This limestone makes excellent building material as has been used in the Cotswolds to give the buildings there distinctive golden yellow colour.
During the Inferior Oolite and Great Oolite times this area was low-lying between shallow sea to the south-west and a swampy, coastal region to the north-east. In these shallow, variable environments the deposition of sediment varied greatly in amount and type from place to place and time to time. As a result the strata exhibit rapid lateral changes in thickness and character and some beds may be restricted to small areas.
In the early 1960’s remains of a partial right femur from a Cruxicheiros(meaning “cross hand”) is a genus of tetanuran theropod dinosaurwhich lived in the Middle Jurassic of England. The type species is C. newmanorum,described by Roger Benson and Jonathan Radley in 2010. The 2010 paper recognized differences between the Cross Hands Quarry discovery and those attributed to Megalosaurus. These differences include lower and broader spines along the animal’s back, and differences in leg and hip bones. The authors renamed the Cross Hands Quarry specimens Cruxicheiros newmanorum; the generic name Cruxicheiros comes from a mixture of Latin and Greek, Latin crux meaning “cross” and Greek cheir meaning “hand,” in reference to the Cross Hands Quarry locality where the fossils were discovered. The specific name newmanorum honors the Newman family, who own the quarry. Cruxicheiroswas a large theropod, but the known material is very limited. The holotype, catalogued as WARMS G15770, is a partial right femur. Additional material from the site probably comes from the same individual as the holotype, based on examination of the matrix of sandy limestone and calcite which make up all the fossils. The additional material consists of “an anterior dorsal or posterior cervical vertebra; a dorsal neural arch; a partial dorsal vertebra; the anterior half of a middle-distal caudal vertebra; a partial right scapulocoracoid; a partial left ilium; the proximal end of a left pubis; [and] numerous rib and bone fragments”. The specimens are now stored at Warwickshire Museum Service (Source Wikipedia).
FINDS
Typical fossils found at this location are bivalves, brachiopods, gastropods, echinoids (such as Clypeus ploti).
Many thanks to Mr Newman for allowing our party to visit his quarry.
UKAFH field trip to Ketton quarry, Rutland on 13th October 2018
UKAFH were fortunate to gain access to this remarkable mile-wide working quarry on Saturday 13th October. A small group of us gathered on this unseasonably mild but breezy day for an excursion into the Middle Jurassic. We assembled in the site canteen for a briefing from UKAFH leader Sam Caethoven and the site management, taking time to enjoy the displays of some of the more exceptional finds to have been previously found at the quarry, before heading into the quarry itself.
Ketton Quarry is an enormous site which provides an extensive exposure of the middle Jurassic from rocks of Bathonian age (dating to around 165 million years ago) to Bajocian age (around 175 million years old). The mile-wide quarry has been worked for many decades and is now 115.6 hectares in size. With full access, this huge quarry provides opportunities to collect fossils from many different beds, however we were limited to an area of spoil where operations were not currently ongoing for safety and practical reasons. Despite this, fossils were still abundant.
The geology at Ketton is complex, with a range of Jurassic-aged rocks recorded. Mostly, three formations are visible in the quarries: the lowest is the oolitic Lincolnshire Limestone which was laid down in the middle Jurassic about 160 million years ago. This large, blocky, rock was formed from small grains of calcium carbonate which were deposited under a warm, shallow sub-tropical sea which was subject to reasonably strong currents. Above this is the Rutland Formation – bands of delta and shoreline muds and sands carried by rivers. Each band, with shelly remains at its base and tree roots at the top, was formed when sea-level rise topped the layer below. Many colours can be seen in fresh exposures of this formation. The exposures at the working quarry (Ketton Main Quarry) are the type formation for the Rutland Formation. Above the Rutland Formation is the Blisworth Limestone, laid down under quiet, shallow, warm conditions during a marine transgression. The Blisworth limestone is full of fossil corals and shells.
Ammonites can be found but bivalves, corals, brachiopods, gastropods, echinoids (such as Clypeus ploti), shark teeth and fish remains are more common. In the past, dinosaur footprints have been seen, along with fragments of their bones, but we were not that fortunate on this occasion.
Blocks of limestone are often full of bivalves, brachiopods, or corals but you need a good geological hammer and a chisel to extract them as they can be very solid, although some rocks will have weathered to the point that fossils can be easily picked out. There were also many loose fossils to collect. Throughout our time on site we were able to find many bivalves and echinoids as well as a few brachiopods and gastropods. Special mention goes to James who took the time to carefully search the fine matrial for quasi-microfossils and found numerous echinoid spines, fish teeth and an Acrodus sp. shark tooth.
At the end of our hunt we gathered in the canteen for refreshments and to enjoy seeing each thers’ finds. It’s quite unusual on a UKAFH hunt for us all to finish together and have somewhere to gather for show-and-tell afterwards and it is always a highly enjoyable part of the day. As well as seeing all the finds and learning more about the site, the quarry staff can also see what we have found, both to share in our enjoyment and to ensure that anything rare is reported and recorded.
UKAFH would like to thank Hanson Cement and the staff at Ketton quarry for allowing us to visit and taking care of us throughout the day, including briefing us, showing us the site and allowing us the use of their facilities.
UKAFH field trip to Withington, Gloucestershire on Sunday 30th September 2018
We were blessed with a warm, dry day for our first hunt at Withington in ploughed farm fields. 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 really is an excellent way to find fossils with little effort other than to look patiently and “get your eye in”. 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, which we obtained special permission to visit, 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 display and 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 the upper field yielded complete and partial Clypeus ploti. A number of members also found ammonites, which was unexpected as ammonite finds at this location have historically been quite uncommon. Some beautiful gastropods were found and one lucky hunter even found a flint scraper!
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).
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.
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.
Natural History Museum – behind the scenes January 29th 2018
On 29th January UKAFH members were welcomed to London’s outstanding Natural History Museum (NHM). The grand, terracotta-faced Victorian museum houses one of the world’s greatest natural history collections, with outstanding specimens on public display and a programme of world-class special exhibitions. However, our visit was all about what is behind the scenes of this great museum.
Our fortunate group of fossil collectors assembled alongside “Sophie” – the most complete Stegosaurus fossil in the world – to meet our host for the day, Professor Adrian Lister, a specialist in mammals working in the Vertebrates and Anthropology section of the Earth Sciences Department. Following a brief introduction we were led into the museum (“follow the jazz hands!”) and through the door from the public areas to the true heart of the museum.
It would be easy to make the mistake of believing the only purpose of the NHM is to educate the public with its displays, interactive facilities, information boards, exhibits and exhibitions. However the NHM is in fact a vast repository of some 80 million specimens and functions as an incredibly important research facility. There is a great deal more behind the scenes of NHM than meets the eye; certainly there is an extraordinary amount of space hidden away from the public areas – a veritable labyrinth of storage facilities, laboratories and research offices. It would be impossible to see and absorb the true extent of this enormous hidden world in a day but our visit provided a brief glimpse into the real world of the NHM, it’s specimens and the people who study them.
We began in a special reception area laid on for backstage visitors which showcases some of the museum’s prized specimens. The small but exceptional display includes diverse examples of the world’s natural history, including fossils and minerals – a snapshot of time itself, if you will. Adrian provided an outline of the day’s programme and introduced us to colleagues Zerina Johanson and Paul Taylor who would lead our party round specimens showcasing their personal research areas.
The NHM repository has its own stratigraphy of a sort: the dinosaurs and marine reptiles fossils are at the bottom, then working up the floors you travel through laboratories, birds, mammals, fish, bryozoa, molluscs, ammonites and so on. Within those categories the arrangements can vary: mammals are arranged by geographical location; bryozoa by geological time; fishes by species. Aside from the many researchers working within the museum there is an army of volunteers who help identify, label and digitise the multitude of specimens held. The NHM is working on an extraordinary digital database which is publicly accessible and searchable and will provide an exceptional resource to professionals and amateurs alike, no matte their location. The digitisation process also facilitates metadata, empowering the indexing and cross-referencing of specimens to make the whole far greater than the sum of its parts.
Introductions over, we divided into three groups to visit portions of the British mammal, bryozoa and fishes collections. We had the great privilege of seeing some truly exceptional fossils and learning more about their recovery, preparation, conservation and use as specimens for scholars all over the world.
I came away from the mammal collection with a greater understanding of the abundance and relative diversity of “ice-age” mammals, learning about acquisition of collections from private collectors, whether by donation or purchase. I also learned that mammoths possessed 6 sets of teeth during their lifetime, each successively larger as the beast grew, and that when the final set was worn down the animal was no longer able to feed adequately so the teeth determine not only the age of the animal but also its lifespan. Paul Taylor (who also regularly writes in our own Deposits Magazine) began by expressing great disappointment that Sir David Attenborough has never mentioned the sadly overlooked bryozoa; by the end of our fascinating tour of the collection we shared his mildly offended incredulity! Bryozoa are extraordinary colonial creatures which thrive in a multitude of ways, show multiple examples of convergent evolution through the fossil record and, despite being almost entirely obliterated by the P-T extinction event (the coloured dots on the specimen drawers told a tragic tale of this wipeout) managed a resurgence which means they still thrive today. Microscopic photography revealed the mysteries of their feeding, breeding and defences. Finally, visiting the fishes with Zerina we saw examples of extraordinary conservation, with the most fragile of fossils being parted from or exposed within their rocky graves. Such extraction can come at the price of fragility and loss of context (the matrix can be as important as the specimen in understanding the living environment, preservation and age of a fossil). We saw exceptional casts and replicas of precious fossils and extraordinarily detailed 3D imaging of rare fossils, all enabling specimens to be handled, observed and studied across the world without the risk of loss or damage in transit of the original, precious fossil.
Following our visit to the collections we visited the Angela Marmont Centre (AMC) for UK Biodiversity. Many of you may not be aware of this incredible free resource but we urge members to take the time to discover a little more by visiting in person or online! Located on the lower level of the Orange Zone of the museum by the Queen’s Gate entrance, the AMC provides a range of services and resources that benefits experts and amateurs alike. Services are as diverse as pest identification, which assists in detecting and preventing crop pestilence and monitoring the spread of pests around the globe; and CITES certification which identifies and prevents the trafficking of rare and endangered animals and the products of such trade. But more generally, they offer access to a large and diverse range of UK fossils which can be handled and studied and a vast array of UK biodiversity reference collection of such as insects, butterflies and bird eggs which can be examined.
The AMC has regular opening hours* for visitors to view the collections and also to make use of facilities such as the London Natural History Society’s library and also to bring in fossils and specimens for identification. Aside from the in-person identification service they offer an excellent free online identification forum at http://www.nhm.ac.uk/natureplus/community/identification. Further facilities include bookable resources such as microscopes, photo-stacking equipment, keys and field guides and workshop space suitable for meetings and training sessions. There are also handouts and information leaflets, including specimen labels, which can be taken away. This magnificent resource, which I have personally made use of on a number of occasions, is already benefiting a number of our members post-tour and we hope to welcome some of the AMC staff on future fossil hunts too!
Last but not least, of course we exited through the gift shops! NHM has a vast range of books and resources to purchase. You can even buy our own book, “A Guide to Fossil Collecting in England and Wales” in the British Geological Survey (BGS) shop inside the museum.
The passion and knowledge of our tour hosts was self-evident and we are most grateful to Adrian, Zerina and Paul and to Christina, Ben and Florin at AMC for their time. We also noted that our hosts had taken the time to understand our group and activities and had specifically shown us examples of specimens that we may have found ourselves, or been able to look for, on past and forthcoming UKAFH hunts. This thoughtful attention to detail did not go unnoticed! Thank you for giving up your time for us to create such a special day.
*The AMC’s opening hours are 10-12 and 2-4pm Monday to Friday, and the first Saturday of the month.
UKAFH weekender at Folkestone and Samphire Hoe, Kent 14th and 15th October 2017
On Saturday 14th October UKAFH took a group out to the Warren, Folkestone for day one of the Kent weekender. We were blessed with unseasonably warm weather as our group of 30 descended the (pleasantly dry) mud footpath down to the beach to begin our hunt through the Cretaceous period! Once on the beach, UKAFH leader Chris Tait briefed the group on the geology of the location and what we might expect to find.
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- Anahoplites ammonite found by Joanna Applegate
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- Anahoplites ammonite found by Eddy Miles
The rocks at Folkestone represent the Albian stage of the lower Cretaceous, 110-105 mya. Lower Greensand is found at the base of the cliff with Lower and Upper Gault clay resting conformably atop, however the clay slumps over the Lower Greensand and is eroded at sea level to release large volumes of fossils onto the beach in this highly productive locality for fossil hunting. During the time these sediments were laid down the UK was at a more southerly latitude in the area of the modern day Mediterranean and a warm sea teeming with life covered the UK. During this time sea levels were transgressing, with the Lower Greensand being deposited as and continued to erode, to be replaced with fine clay sediments once nearby land was completely submerged.
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- Sieving for fossils
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- Large shark tooth find
The Lower Greensand is less fossiliferous as the near-shore environment it represents was less suitable as a habitat but still contains excellent fossils such as ammonites; the Gault Clay, however, is packed with diverse fossils, some with exceptional preservation. Ammonites, belemnites and molluscs are common; nautilus, crabs, crinoids, fish remains, shark teeth and scaphopods can be found, along with rare finds of reptilia. Examples of all of these were found by members of our hunt group!
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- Joanne’s selection of finds
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- Jahaan’s ammonite
Phosphatised preservation is typical but quality is variable, with examples often fragmented or in nodules. However many examples are preserved in superb detail in pyrite and those which are newly emerged from the clay can retain some or all of their nacrous shell. Bivalves and molluscs which are newly exposed are often extremely fragile and are rarely collectable unless carefully removed along with the surrounding clay, but ammonites are more durable and make marvellous specimens to add to a collection.
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- Shark vertebra found by Joanna
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- Isabelle’s sand tiger shark tooth
Soon after we reached the beach heading towards Copt Point the finds were already plentiful. Partial regular and heteromorph (partially uncoiled) ammonites and bivalves were quite common and finds increased as people “got their eye in”. Some of the group progressed quite quickly along the beach to inspect the slips of clay for freshly washed out fossils and check out the shingle between the large rocks and boulders on the foreshore. Others remained nearer the start of the beach, working methodically through the shingle by hand, with a trowel, or dry sieving, in search of smaller finds like shark teeth.
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- Sindia’s Euhoplites nitidus
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- Anahoplites planus
Several members of the group found shark teeth, with Isabelle finding the largest example. At the other end of the scale, Sam found a small but scarce Acrodus shark tooth while sieving using a 3mm mesh. Sieving is a good technique to remove sand and search for small fossils which wash out higher up the beach because they are lighter. Sieving and shingle-searching up the beach yielded crabs, solitary corals, urchin spines, shark teeth and vertebrae as well as fish teeth, a turtle bone and the day’s star find, a swordfish tooth!
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- Swordfish tooth found by Brian Allen
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- Fish tooth found by Sam Caethoven
By the end of the day we had a really great selection of finds amongst the group!
The following day we were greeted with yet another gloriously sunny autumn day, enhanced by the towering white cliffs of Dover above our meeting point as Samphire Hoe Country Park. We had another full house of attendees and headed west along the beach to hunt for fossils amongst the chalk boulders on the foreshore. Aidan Philpott, UKAFH Leader, explained the geology and identified local fossils to look for to the group. The lower chalk (also known as the grey chalk) at Samphire Hoe is from the Cenomanian stage of the Upper Cretaceous so yields fossils aged 100.5 – 93.9 Mya.
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- White cliffs of Dover
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- Looking towards Samphire Hoe
Common finds are brachiopods, bivalves and echinoids. Sponges, shark teeth, worm tubes, gastropods and fish can also be found and, rarely, ammonites. As well as beautifully preserved fossils within the chalk, some echinoids and shells and many sponges form flint casts which can be washed out of the chalk and found in the shingle. Attractive pyrite crystals can also be found in the chalk.
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- Echinoid in flint block
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- Huge clam found by Chris Tait
Our first find of the lay was an eroded echinoid inside a flint block. UKAFH leader Chris Tait then found a large section of clam. These giant molluscs are mostly found broken into small pieces so this was a really nice find. As the day progressed a good variety of finds were made including echinoids, shark teeth and brachipods.
Samphire Hoe isn’t the easiest location for fossil hunting as you need to scrutinise the loose chalk boulders on the foreshore carefully for signs of fossils and then extract them very carefully with a chisel to ensure they are not damaged. You can also hammer the boulders to break the chalk up in search of fossils so work, tools and care are needed to have a good chance of finding fossils here. Once extracted, however, preservation is usually excellent, with fine details clearly visible.
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- Beautiful Echinocorys echinoid
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- Remains of sponge in chalk
Cleaning chalk fossils is easy, requiring little more than dry brushing the remaining chalk matrix with a soft brush (a children’s toothbrush is ideal) to remove any chalk remaining on the fossil surface. As chalk is very soft, you can easily remove larger amounts of remaining chalk with a blunt knife or craft knife until you approach the surface of the fossil and switch to brushing.
Finds were pleasing but not abundant, however everyone enjoyed the hunt and the sunshine day.
Chris, Aidan and Sam, your UKAFH leaders, would like to thank all of our members and attendees for joining us on our weekend fossil extravaganza and we look forward to seeing you all soon!
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Photos from UKAFH’s fossil hunt at King’s Dyke Nature Reserve, Sunday 13th August
UKAFH King’s Dyke Nature Reserve Fossil Hunt on 2nd July 2017
The 2nd July was a momentous day in UKAFH history being the last hunt that founder Craig Chapman would lead before stepping down from leadership duties and we were very hopeful it would be a good hunt. We weren’t disappointed!
I had only been to King’s Dyke once before on a blisteringly hot day and got quite pink in the sun! So I was relieved that there was some cloud cover and we didn’t have to worry about people getting sunburnt.
The hunt was very well attended with about 30 or so people eager to pick through the clay in search of ancient treasure. I must thank the quarry owners for having refilled the area the day before giving us 2 large areas of fresh clay to pick through. After a brief introduction at the identification board we headed up to the smaller heap just up the hill and the hunt was on!
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- Large ammonites
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- Typical King’s Dyke ammonites
One of the best features of this locality is that is suitable for all the family and is productive enough that hunters are guaranteed to go home with something, and everyone who wanted one of the plentiful (and beautiful) flat ammonites found at least one. Belemnites are also very common and range in size from a few centimetres to several inches (sorry about mixing metric and imperial!) The largest complete ones are not to be found everywhere and are quite the prize and I was lucky enough to find a couple of beauties. James found the biggest most complete one and was justifiably delighted with it!
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- James and an enormous belemnite
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- Unusually well preserved ammonite
After about an hour or so at the secondary heap we headed down into the main larger fossil hunting area where we were hoping to find some of the other things that can be found from this section of the Jurassic. Fish, crocodiles, ichthyosaurs and plesiosaurs are all known from here but are not common and are a major highlight if you are lucky enough to spot them. Between us we found 5 Lepidotes fish scales and even a couple of fish coprolites.
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- Lepidotes scale
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- Fish coprolite
I am deliberately leaving the best till last, and chronologically they were found last, all within the last 30 minutes of our time hunting. It wouldn’t have been a proper UKAFH hunt in the Jurassic without Craig finding a vertebra and he duly obliged with a lovely ichthyosaur vertebra. I chipped in with 20 minutes to go with my most spectacular UK find – a plesiosaur vert which truly made my day. Then just as we were packing up, a random family who weren’t even part of our group arrived and the young man hunting with his Mum and sisters found a “weird belemnite” that we were not at all jealous to identify as a plesiosaur tooth! They were on their first ever fossil hunt so I shamelessly plugged UKAFH as a great group to join!! Maybe we’ll see them again on a hunt another time, who knows.
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- Chris’s plesiosaur vertebra
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- Plesiosaur tooth
Either way it was a great day and the feedback was very positive. Thanks again to the quarry owners for the fresh clay to hunt through and I look forward to hunting there again next month with a new group.
Chris Tait
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- Craig’s ichthyosaur vertebra (of course!)
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- Craig – we love you! THANK YOU FOR GIVING US UKAFH xx
Fossil Hunt at Pett Level, East Sussex 4th June 2017
On Sunday the 4th June UKAFH descended in number upon the Sussex shoreline for a fossil hunt from Pett Level towards Fairlight – a stretch of coastline famous for its dinosaur foot prints, foot casts and dinosaur bone.
We began with a short explanation about the geology and what could be found. Exposed in the cliff here is the lower part of the Wealden group of formations, a deposit of sandstone, siltstone, clay and conglomerates dating to the Lower Cretaceous, about 140 million years ago. It was deposited in a vast river system and flood plain at a time of exceptionally warm global temperatures and an area of extremely seasonal weather. The seasonal nature of the palaeoclimate helps explain why this deposit came to be so fossiliferous and preserve the famous foot prints and casts. We can imagine the area as a warm, wet, densely vegetated environment, indicated by the great number of plant remains found here. The numerous rivers and lakes were abundant with life, made apparent by the dense assemblages of bivalve fossils, abundance of fish bone, scales and teeth and most notably by the huge slabs of bioturbation found on the shoreline – the trace fossils of creatures moving through the fluvial mud. This mud was also deposited on the river banks where huge (and sometimes small) dinosaurs such as Iguanodons or Baryonyx would stop for a drink, leaving their distinctive foot prints. Then came the dry season, which was extreme enough to cause bush fires – indicated by the presence of charcoal in the formation – the rivers dried up and the lakes became anoxic, aiding preservation. This was followed by the wet season, with intense storms and flooding, depositing larger grained sediment across the floodplain, burying the foot prints to form foot casts and preserving the remains of plants and animals to be found here 140 million years later.
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We didn’t have to worry about such seasonal extremes on this fossil hunt however, as the sun was shining while we enjoyed the summer warmth with a refreshing sea breeze. There was a lot to see as he headed west towards Fairlight. We saw large blocks of bioturbation and ripple marks preserved in claystone, the black remains of plant material were also abundant. The foot casts and prints were unfortunately sparse compared to previous UKAFH visits however a spectacular and rare theropod print was found. We also found huge slabs of Cliff End Bone Bed, a conglomerate which as the name suggests contains a lot of a bone fossils. These slabs contained clearly defined fish scales and teeth – those members lucky enough to find small pieces of bone bed took them home to treat with a mild acid such as vinegar to extract the fossils within. Other finds included bivalves, the odd rolled dinosaur bone, fish bones and of course Nicky Parslow found an echinoid preserved in flint, something that’s become a trademark of hers. Another unusual find was the barrel of a gun found by Chris Avis. It was debated as to whether it was an Air rifle, a pressure washer, or even a WW2 American paratrooper rifle! I hope Chris has it looked at and lets us know the conclusion.
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Although the finds were few and far between on this occasion I hope everyone enjoyed a sunny and informative day on the beautiful Sussex coastline and I hope to see you all again soon on another UKAFH hunt.
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Please note. This stretch of coastline is a SSSI. Do not dig into or hammer the bedrock or cliffs – only loose fossils along the foreshore should be collected and any significant finds should be registered with Bexhill Museum. The often abundant foot prints and casts must not be collected – instead take a photograph and leave them for everyone to enjoy.