Deep into the Past

In 2019 Shetland Museum assessed its fossil collection, in response to an initiative by the National Museum of Scotland to review Natural History Collections across Scotland, funded by the John Ellerman Foundation. We were visited by palaeontologist Dr Susan Beardmore, focusing on fossil collections in particular. We enlisted the help of a generous volunteer to organise our collection ahead of her visit. Here he explains why fossils fascinate him and what he discovered in our collection.

I have always been amazed by Mother Nature since I was a child. The shapes, the colours, and the phenomena which surround us are endless. This is the main reason why I chose to become an earth scientist.

My name is Máté Dániel Petróczy and I am a university student from Hungary, who took a break in his MSc studies in 2019 to discover these amazing isles called Shetland, one of the 147 UNESCO Geoparks. After two months in Shetland I had the opportunity to meet with Natural Heritage Project Officer, Paul Harvey and Geopark Manager, Rory Tallack at Shetland Amenity Trust to find out whether I could get involved in an earth science related project. This is how I met Curator and Community Museums Officer, Dr Carol Christiansen and how I was introduced to Shetland Museum’s fossil collection.

By definition, fossils are “remains of a prehistoric animal or plant preserved by being buried in earth and now hardened like rock… Other forms are traces left by animals, such as their footprints or trails. Fossils provide important information about the dates of different geological periods” (Oxford 1993: 354). Different geological periods can imply thousands, millions or even billions of years. This is how we can witness prehistoric events, have an insight into the ecology of the past, and understand the process of evolution. In my definition, a fossil is a time machine that can take you deep into the past.

Fig. 1. Skeleton of a Megaloceros giganteus (extinct) at the National Museum of Scotland and artist’s impression of the same. (left) Creative Commons Ballaugh Elk.xcf , used under CC BY Shetland Amenity Trust, cropped. Crosswordclue / CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0) [accessed 11February 2020]. (right) Image credit: Philip Newsom, IG: @philipnewsom.

How do fossils form? It all starts with a catastrophe, or call it a fortunate event. It is catastrophic for the organisms because they were buried in sediments, lava, or tree pitch (forming amber) in a very short period of time. For palaeontologists, however, it is a lucky case, because the burials have kept the organisms protected from erosion, weathering, or biological degradation. The remains can be preserved for eras, so scientists can access essential information from the geological epoch when the deposition occurred (Géczy, 1984: 34).

Fossils are found worldwide, including Shetland. The Museum’s fossil collection contains donated specimens found locally over the past 50 years. The fact that you can hold a preserved ancient creature, or its trace in your hands is fascinating. This is why I was more than excited when I began to investigate Shetland Museum’s fossil collection for the very first time.

My main role with the fossil collection was to make a proper catalogue of them. This process involved sorting fossils out from rocks that did not contain organic remains or traces, creating a spreadsheet of the fossil collection starting with Shetland Museum’s collection catalogue, taking quality digital photographs of each fossil, and identifying as many as I could.

Figure 2: Fossilised plant stem of Psilophyton sp., possibly dawsonii in Old Red Sandstone found at Fair Isle (NAT 1995.61), and artist’s impression of the species (NAT 2016.142)

There are several different kinds of fossils found in Shetland. Plants such as Psilophyton dawsonii evolved during the Devonian period when life on the land was barely starting to flourish. Most fossils from the collection date to this important period. During this time there could have been geological events like marine transgression (the rise of global sea level), or other burial actions which caused dead creatures to remain in sediments.

Figure 3: Sand-filled boreholes made by worms in Devonian sandstone

Shetland Museum also has trace fossils, which aren’t remains of animals but their activities, such as the boreholes of worms. This specimen perfectly represents the biological activities that occurred in the sediment itself. Bioturbation is the reworking of sediment caused by creatures. “In modern ecological theory, bioturbation is now recognised as an archetypal example of ‘ecosystem engineering’, modifying geochemical gradients, redistributing food resources, viruses, bacteria, resting stages and eggs” (Meysman, et al, 2006: 688). Having a bioturbated rock sample can lead to understanding the ecology of the geological environment thousands or millions of years ago.

Figure 4: Stegotrachelus finlayi (NAT 1995.54) and Dipterus valenciennesi (NAT 8561)

Prehistoric fish of various species have been found buried in sediments in Shetland. A bony fish called Stegotrachelus finlayi was first described from evidence found in Shetland (Finlay, 1926) and Dipterus valenciennesi was a species of lungfish also found here. Shetland Museum has fossilised examples of both species.

Isn’t it amazing how we can have an insight into the past by these information-retaining rocks? Species, ecosystems, geological periods and extinctions, the history of the earth holds millions of untold stories that are still waiting to be revealed.

“…whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.”

Charles Darwin, On the Origin of Species

References

Finlay, T. M. et al. 1926. The Old Red Sandstone of Shetland. Part I. South-Eastern Area. With an Account of the Fossil Fishes of the Old Red Sandstone of the Shetland Islands. Transactions of the Royal Society of Edinburgh, Earth Sciences 54 (3): 553–572.

Géczy, Barnabás. 1984. Őslénytan. Budapest: Tankönyvkiadó.

Meysman, F., et al. 2006. ‘Bioturbation: a fresh look at Darwin's last idea’. Trends in Ecology & Evolution, 21 (12): 688–695.

Oxford Advanced Learner's Encyclopedic Dictionary. 1993. Jonathan Crowther, ed., 2nd rev. ed.

Most fossils in Shetland are found within Sites of Special Scientific Interest and are protected by law. You must have the landowner’s permission to remove a fossil. If you find a fossil, it’s best to leave it where you found it. Please refer to the Scottish Fossil Code.

If you already have fossils you wish to donate to Shetland Museum, please enquire at Reception, email info@shetlandmuseumandarchives.org.uk, or telephone 01595 695057.

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