ichthyosaur
UKAFH field trip to Doniford Bay, Somerset on 15th September 2019
On 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!
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.
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.
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.
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.
The Royal Institution lecture – Jurassic Britain: Rediscovering dinosaurs and ichthyosaurs.
I’m pretty sure I’m the only person in the room who isn’t accompanying children. The awaiting audience are chatty and excited. The child behind me already knows what most of the fossils on the table awaiting description are. “Baryonyx claw!” is exclaimed. “What is the word for fossil poo?” encourages dad. “Coprolite!” the excited boy declares loudly.
It is Friday 2nd February and palaeontologist and UKAFH patron Dean Lomax is about to take us on a journey back to the amazing British finds that sparked the original dinomania in the 1800s. From the ‘invention’ of dinosaurs to the great granddad of T. rex, he reveals British dinosaur and ichthyosaur discoveries, including recent identifications of new species and some incredibly rare finds.
The Royal Institution event, Jurassic Britain: Rediscovering dinosaurs and ichthyosaurs, welcomed all ages but was specifically aimed at ages 7+. These are children who know their dinosaurs and who, with encouragement for and enrichment of their passion, might become the next generation of palaeontologists.
Dean begins thus: Before Jurassic World and Jurassic Park was Jurassic Britain. This inspired him as a child to pursue palaeontology as a career. And it’s been quite a career so far, including authoring the outstanding book, Dinosaurs of the British Isles, along with Dr Nobumichi Tamura, on which this talk draws.
Dean captivates his audience with tales of Victorian gentlemen and scholars who strove to understand and describe the mysterious fossil bones that were being discovered, which were found to have some similarity to lizards and led to the term “dinosaur” being coined by Dr Richard Owen in 1842. Yes, dinosaurs are a British invention! Indeed, the first three dinosaurs ever described were British and because we were at the forefront of this new science as well as possessing a large number of dinosaur fossils, Britain had a good many “firsts’ in the record books of dinosaur discovery. Our unique geology means that around 60 dinosaur species are known in Britain from across the whole of the Mesozoic era, making up over 4% of all dinosaurs.
Dean talked us through the timeline of momentous discoveries, amply illustrated with images, artists’ reconstructions, video footage, genuine and replica specimens and visualiser displays. It has been quite a journey from Victorian times to today, as the poorly-understood fossils were imagined and brought to life as the Crystal Palace dinosaurs which are distinctly inaccurate by modern standards as the science of palaeontology has grown and drawn upon other disciplines to understand the fossils and many, many more specimens have been discovered and compared.
We then proceeded on a journey through the British Mesozoic, introducing many notable British dinosaurs, many of them ground-breaking discoveries at the time. From the Isle of Skye to the Isle of Wight we encounter British dinosaurs large and small, complete and fragmentary, early to late, carnivore, herbivore and pecscivore! We travel overseas too, finding examples of British dinosaur and marine reptile fossils in far-flung corners of the globe. Indeed, Australia’s first dinosaur, Agrosaurus, later transpired to be a Thecodontosaurus fossil from Bristol!
The topic of migrating fossils was prominent in Dean’s continuation into Ichthyosaurs, his personal specialism. Ichthyosaurs are not dinosaurs but marine reptiles, having a common ancestor which predates the emergence of the dinosauria. Dean’s own “evolution” as a palaeontologist is closely tied to marine reptiles through his early fieldwork in Wyoming to volunteering in his local museum and discovering an exceptional genuine fossil ichthyosaur in the collections which was thought to be a cast! Dean’s subsequent work describes a journey of hunting down “lost” British fossils hidden away in archives, small museums and overseas, re-examining them and, in two cases, recognising new species. It is a tale of caveats: many fossils are repaired, enhanced or even composites, giving the appearance of a complete specimen but being scientifically inaccurate.
Once Dean had completed our journey from ancient to modern times via the Victorian, questions were invited from the audience. I’m not sure if I was more impressed by the quality and diversity of the questions from the rapt young audience or the fact that Dean could answer them all! Could T-rex jump? Probably, but if he landed badly he might struggle to right himself and a bad fall resulting in a broken limb could prove fatal so he likely didn’t risk it. I’d never considered the question and I’m fascinated by the answer!
I’d like to thank Colin Tucker at the Royal Institution for sending me a ticket to the event.
If you’d like to read more from Dean about British dinosaurs Dean’s article for Deposits magazine is here:
Dean Lomax is an internationally recognised multi-award-winning palaeontologist, science communicator and author. He has travelled the globe and worked on many fascinating projects, from excavating dinosaurs in the American West to describing new species of extinct marine reptiles. Dean is passionate about communicating palaeontology with the public and regularly appears on television, including as series advisor and expert co-presenter for ITV’s Dinosaur Britain. He has written two books, numerous scientific papers, and many popular articles. Dean is a Visiting Scientist at The University of Manchester and patron of the UK Association of Fossil Hunters (UKAFH).
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