weald clay

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

Fossil Hunt at Smokejacks Pit 15th July 2017

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The Quarry

On Sunday the 15th July UKAFH met at the world famous Smokejacks Pit – a large clay pit situated just outside Ockley 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.

The pit cuts through a section of the Wealden group, specifically the Weald Clay. The clay was deposited in a lake and floodplain environment during the Barremian stage of the Cretaceous period about 129-128 million years ago. At this time, the environment was warm and moist due to England’s then position in mid-latitudes but the climate was exceptionally seasonal with ground scorching dry seasons and intensely stormy wet seasons. Although this weather system may sound inhospitable, the cycle of organic deposition provided by the flood waters created a fertile ecosystem rich in both aquatic and terrestrial fauna and flora – perfect for giant dinosaurs! The diversity of fossils to be found here is quite extraordinary; some beds are extremely rich in plant material, others are ripe with insect remains.  Fish, shark and shrimp are common too in the right layers and crocodile, pterosaur and of course dinosaur remains can be unearthed here with a good eye and a bit of luck.

Weald Clay expert Peter Austen provided us with a fantastic, in depth presentation on the Weald Clay and showed us examples of what could be found in the pit. Peter’s roadshow introduced us to the diversity of insects for which the pit is known (7 new orders of insects and numerous  species). He 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) and plant remains and the well-known concostracans, small shrimp-like creatures which bear superficial similarity to bivalves. Peter provided a handout and a stratigraphical column to assist the group members in finding the various fossil beds. This was particularly beneficial in helping members determine where to look for certain fossils.

We entered the pit very excited and eager to see what we could found. We were lucky with the weather on this occasion; although rain threatened it remained dry – any downpour could soon turn the clay into mud – and we were grateful for it being overcast as the site is extremely exposed and will become uncomfortably hot in the sunshine very quickly, especially when traversing the steep quarry sides.

We began by walking the quarry slopes in search of any fossils visible on the surface. This proved fruitful for Chris Tait, who stumbled across several pieces of crocodile tooth enamel, and Mark Goble who found a broken block containing a large amount of fish material thought to be Lepidotes. Some then headed to the base of the quarry in search of rocks containing insect remains. Sam Caethoven struck lucky with a beautiful wing and wing case side by side in the same block. Some headed for the middle of the slope in search of fish remains: Dan Slidel, who is a geoscientist, took time to investigate the stratigraphy and found fish scales and an abundance of concostracans while Betsy Ooms found the most exquisitely preserved shark tooth.

By the end of the hunt many of us were digging in a bed high up the slope which is full of plant material and is known for an abundance of dinosaur remains. Notable finds include a large piece of bone found by Mary Bite, a beautifully detailed bone found by Seth Cook, an Iguanodont vertebra found by Katherine Combe and a huge crocodile tooth found by Mark Goble, as well as many other bone fragments. However; the prize of the hunt and possible of the year so far goes to Nicky Parslow who found a huge Theropod tooth about 5 cm in length. The tooth was rushed to the Natural History Museum for identification and was examined the very same day.

NHM staff advised: “Your find was of immediate interest, with the curator, Paul Barrett, coming down to identify it this afternoon.  He has identified it as the tooth of a large theropod. He considers it an exceptional find as they are not commonly found. It is not from a Baryonyx but is from an indeterminate large theropod. Unfortunately, it can’t be identified any further as the teeth of these animals are all very similar and there are not enough identifying features to distinguish it from the various other species.”

Peter Austin has since confirmed that this is the only theropod tooth to have been found at Smokejacks apart from Baryonyx so it is a very significant find from the pit! We hope to seek further advice on the tooth in case more information can be found and we are all really excited to try and learn what large, ferocious beast this may have come from.

 

Smokejacks pit is not always as productive as this hunt assumed so I am really proud that everyone made some varied and exceptional finds on this occasion.

Thank you so much to everyone who came and made the day incredible. A huge and special thank you goes to Peter Austen and Joyce for sharing their expertise and organising access at such short notice.

We will, of course, keep everyone posted on the theropod tooth.

 

Aidan Philpott