My days on the Leedsichthys project at the Peterborough Museum.
As a volunteer in the geology department its like a dream come true.
Day 1 and 2: After being introduced and under the expert guidance of Nigel Larkin who is a natural sciences conservator specialising in the excavation, preparation conservation, curation, storage and display of geological, paleontological, archaeological and osteological specimens. We were shown techniques in how to stabilise the base of various sized clay matrixes that hold bones from the Leedsichthys that where originally found around 10 years ago. With Plaster of Paris jackets applied at the dig site when found and in order to keep the bones in place for future research.
And now the Peterborough Museum with funding is in a position to bring these pieces out of storage and continue to work on them in the hope of piecing them together at a later date.
My first two days on the project consisted in reducing the weight of a large clay matrix slab by a couple of inches in order to have sufficient room to apply a fair sized thickness of plaster of paris which would, in turn help to increase stability. Just to help the stability process we also added an acetone / paraloid mix in various strengths into the clay cracks which when dry also aided as a bonding agent for our first layer of plaster of paris.
Top tip for mixing paraloid / acetone mix: Tie your paraloid beads into a small piece of muslin and suspend in jam jar while ###### the lid on this helps with dissolving process of the beads.
So what you can actually see here is the reverse side of the find (the base) with the bones being held in place by the previous dig site jacket. When we are satisfied that the base is secure after our layers of plaster of paris and muslin we will then flip it over to take the old top jacket off to expose the bones in readiness for prepping them out of the clay matrix.
Layering the plaster of paris was like icing a cake using various sized knives in order to give it a smooth finish. You had to work it a reasonable steady pace as the mixture set very quickly also if possible not to let the new mixture touch the old top layer plaster jacket as this would hamper removing the top jacket.
There are several pieces of clay matrix slabs so we will perform this prepping technique to all of them.
Day 3: Back in the prepping laboratory at the Peterborough Museum to help finish off the plaster base on the largest clay matrix slab.
After a good clean up after us around the Lab (plaster of paris is a very messy business). It was decided to retrieve two larger jacketed slabs out of storage in order to look at them further and to assess our plan of action.
Now these slabs where quite heavy with added weight from the made to measure wooden palate structures underneath them that Nigel had made to increase stability so it was all hands on deck to move them into position and onto our prepping table. We have been taking photos as often as possible with each and every step of the way with this project and making notes of any written marks that may have been applied to the jackets at the dig site. More photos were taking of the cast before we decided to take the top cast off to expose clay matrix with the bones encased within.
There were lots of boney elements intertwined with the clay with no formal identity as such to what we are looking at as yet with this particular slab. So again under the guidance of Nigel Larkin we tentatevly removed some small fragments of wood with tweezers and scalpels that had adhered themselves to the bone and clay.
Nigel had outlined in precise detail how best to start the cleaning process using some acetone and air abrasives on the bones and how to remove foam material that is connected with the original plaster the cast when jacketed at the dig site. This will enable us to reapply fresh plaster of paris to enhance the stabilizing process as we work on and around the clay matrix. To which hopefully I’ll be taking part in on my next visit to the museum.
Day : 4 ( 13/10/2015)…Back at the Museum for a catch up with other volunteers to see what stage we are at and to learn any new techniques that have been applied for the restoration of the Leedsichthys.
With PPE applied i.e. face masks and gloves we started to remove the old foam and any old overlapping plastered muslin. Also with the aid of an extraction unit to catch any airborne dust particles from the foam as we used our scalpels.
When satisfied that a section of the outer clay was exposed with as much foam and debris removed as possible. It was then decided to add a 15 per cent acetone paraloid solution to the clay not only to help strengthen it but by also to act as an adhere for the plaster of paris to stick to.
With a combination of plaster of paris and muslin we worked our way around the outer edge of the clay slab applying the techniques I’ve just discussed.
That was me done for the day looking forward to my return visit.
Day 5 : 15/10/2015..I was lucky enough to help out at the Museum’s storage facility today to help stabilise a large clay slab with lots of Leedsichthys bone elemnets attached to it. This process did indeed take quite a bit of Plaster of paris and muslin to fill cavities that are around the base of the slab. But the work is vitally important as the clay is quite thin in places so we need a strong base in order to work some of the plaster of paris up the sides to support any overhanging clay matrix.
We estimate this should take at least two days to complete if I’m fortunate enough to resume with this I’ll keep you updated on how it’s going.
Day 6: 10/11/2015
If I apply the phrase “Absence makes the heart grow fonder “can I use this for today’s visit to the museum…erm…yes...definitely.
Especially as we had the pleasure of meeting Professor Jeff Liston who is a world expert when it comes to working with the Leedsichthys problematicus. Just before Jeff briefed us on what duties we would be carrying out today he dropped in the classic line ( jaw dropping time ) “ As you know we are working on the most complete Leedsichthys problematicus…in the World. “
Heres a you tube clip about Jeff Liston working on a
We gathered our senses and composure to continue tentativily working away at various spots with acetone. To clean away old paraloid solution that had been applied at the dig site to reveal more tell-tale bone.
Also the piece we were working onto today has been identified as one of the head plates where we have now exposed the rostrum as well.
All in all it was another therapeutic few hours enjoyed by all the volunteers on this project.
Day 7: 17/11/2015
Back in the museum for a few hours to catch up with other volunteers on the project and to summarize on what stage we are at. Also to learn any new techniques needed as more and more bone is revealed.
Nigel Larkin had returned for the day to see how we were getting on and to further oversee the practices he had taught us on the first week of the project. We all feel quite comfortable in our new found prepping skills. But even more so with the presence of Nigel as he seems to exude some sort of air of confidence.
For example on my last visit I was removing some old paraloid from a section of bone by gently brushing some acetone over the bone then using a sharpened wooden spatchuler to remove the residue. But I found the residue congealing faster than I could remove it so Nigel showed us how to confidently remove the residue with sharp scalpels with the blade flush and flat to the bone going with the grain. In order remove the sticky residue then gentle wipe over with Lint free paper which certainly made all the difference to bring out all the hidden contours of the bone and its beautiful brown colouration.
Jeff Liston was also present busying himself with further research on identifying the bones as they become more apparent. Jeff had identified one of the larger slabs as a Right Hyomandibular which helped work on to remove any lose clay form the edges in order to strengthen the cracked but stable clay edges for consolidating. We noted on the wooden pallet left side and right side then marked up some zip lock bags ( Left side and Right side ) to put loose clay matrix in for further studies i.e. Macro-Palaeontology. Any recognisable bone fragments that we encountered we put on the top of the slab for consolidation at a later date.
That’s me done for today…speak soon.
…..Where was I, oh yes I remember now, working on the Leedsichthys project with a team of volunteers and some experts in this field, how could one possibly forget.
The chilli morning air is no bother when focused.
It certainly does seem a long time since I was in the prepping room of the Peterborough Museum. But as I’m sure you are aware especially the musuem voulnteers amongst us. Work and family life always take first place, but when you get amongst the fossils again everything ticks along and fall into place nicely.
There is still plenty of work to do as you can imagine when working on a specimen labelled as the World’s Biggest Fish. So as uaual we tentatively brushed over the old Paraloid that was used at the dig site to stabilize the finds. Armed with an array of small brushes and sharpened wooden picks as not to scratch the bone.
Very satisfying and therapeutic few hours with my work colleagues and especially nice to catch up with Jeff Liston and ask when his forthcoming book about the Leeds brothers will materialise.
Speak again soon.
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