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

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