This is a representation of what Leedsichthys is thought to have looked like. It probably did not have a huge limpet on its head and did not fly as this image suggests!!
‘The Big Dig’The story of the excavation of a gigantic Leedsichthys fish in Summer 2002 Kay Hawkins Leedsichthys is a large, filter feeding, bony fish of Callovian (Middle Jurassic) age, a member of family Pachicormidae. It was first discovered in the 1880’s by Alfred Leeds and is now the subject of a PhD being undertaken by Jeff Liston from the Huntarian Museum in Glasgow. At the beginning of July I was looking for something interesting to do in the long summer holidays ahead. Roy Clements, the Head Curator in the Geology Department at the University of Leicester, put me in touch with Dr David Martill from Portsmouth University who was helping to coordinate a dig to uncover and remove the remains of a very large Leedsichthys problematicus which had been discovered in the Oxford Clay the previous summer. I soon found myself joining a team of experts and volunteers, led by Jeff, who were camping in a disused brick pit near Peterborough. I stayed with them for most of the next ten weeks, returning home occasionally for a bath and to sleep in a proper bed. The facilities on site were very basic but we did have fresh water, a portaloo and access to showers. We ate well and even slept well when we got used to the freight trains rattling past in the early hours of the morning about 10 metres from the tents! We often had a campfire in the evening and when we needed to escape from the pit for a few hours we walked to the nearest pub about a mile away for a drink or two……or more. |
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This is a representation of what Leedsichthys is thought to have looked like. It probably did not have a huge limpet on its head and did not fly as this image suggests!! |
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For most of the summer the weather was hot and sunny, the clay was dry and we were able to carefully remove it using hammers, chisels and trowels. When a bone was discovered we worked with dental tools to delicately remove the rest of the clay. It was slow work but our patience was rewarded as both pectoral fins and many bones from the gills and the skull were uncovered. It turned out that there were many more bones than anticipated, spread over a wide area and as a result the Leedsichthys was soon given the nickname Ariston because the bones went on, and on, and on!! When a bone was uncovered it was mapped onto a large sheet of plastic, given a unique number and then lifted out of the ground. Small bones were very carefully removed from the clay, wrapped up in tissue paper and put in plastic bags. Each bag was then given the same number allocated to the bone on the plastic sheet. Large, and some very fragile bones were lifted in a different way. A deep trench was dug around the clay containing the bone. The bone and clay were then covered in tissue paper and plastic before being covered in a protective plaster jacket. Once the plaster had dried the whole thing was separated from the clay below, lifted and taken away to be stored somewhere dry. Some of the larger plaster jackets were very heavy and had to be removed by a large mechanical digger. |
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Just a few of the many large bones that we uncovered. One, towards the top of the picture, has already been jacketed in plaster |
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It
did rain occasionally and when it did working conditions were less
pleasant. The clay quickly turned to thick mud and the bones were much
more tricky to excavate. We carried on though, mopping up the water with
sponges as we worked and getting very muddy. This dig was of great scientific importance as it was the first time that the remains of this 150 million year old fish had been mapped in the ground. It was also the first time that some bones were seen, including the parasphenoid that I was very fortunate to discover. The significance of this dig made it an excellent subject for a television programme called ‘The Big Dig’ and we were filmed on several occasions during the summer. In November we all returned to the dig site for three days with a television crew to film the main scenes for the programme. Dr. Sarah Gabbott, a lecturer at the University of Leicester, was one of the presenters and a few other Geology students joined us as volunteers. It was a very interesting experience! Look out for it on Channel 4 later this year. |
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The site turned into a mud bath after a couple of days of rain |
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A dig like this does not happen very often so I was very fortunate to get the chance to participate in a second dig at the end of September. A student from Portsmouth University had found the remains of an Ichthyosaur, a marine reptile, in a cliff near the Leedsichthys dig site. So, for the last couple of weeks, I also helped him excavate and remove the bones of what turned out to be an almost complete skeleton about three metres in length. The digs were both great fun but very hard work. They were, at times, physically demanding and often required a great deal of patience and attention to detail but were extremely rewarding, particularly when something of great importance was discovered. |
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Me with Bill, another volunteer, and the parasphenoid that was being trenched ready for lifting |
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I had a fantastic summer, met many interesting people and made a lot of new friends. I have learned many new things about invertebrate palaeontology and have discovered that I have a great interest in vertebrate palaeontology. I have already been asked to work on the Leedsichthys dig again when it is reopened in the summer and I hope to have the opportunity to participate in many more digs in the future too. Kay Hawkins
Section
C Student Representative, Geology Department, University of Leicester.
Photographs taken by Jeff Liston |
