Investigating Fossils. Wilson J. Wall

extinct species, such as Moas from the southern hemisphere, has given an insight into the rate of disintegration and associated bacterial contamination (Oskam et al. 2010; Allentoft et al. 2012). All these biochemical analyses and insights are, of course, in addition to the implausibility of a blood‐sucking insect of the right type being caught in amber. A better chance of finding longer strands of DNA from ancient extinct species comes with the sometimes ignored natural preservation technique of freezing. This is the situation commonly found in permafrost.

      There are some very good cases of preserved remains, most notably mammoths, in permanently frozen ground. The excitement that such discoveries produce is not confined to the past, and neither is it confined to scientific circles. In May 2013, a preserved woolly mammoth was discovered in Siberia and became widely reported, including in the UK press (Daily Mail 2013). So common are mammoth remains found that there is a well‐developed trade in the tusks, known as ‘ice ivory’ and in 2018, there were reported to have been more than 100 tonnes traded, usually for carving into small pieces in the far east. This trade has become so widespread that it has become a concern that poached ivory is being smuggled and traded within the ‘ice ivory’ trade (Cites 2016, 2019).

      The mechanisms of taphonomy, which is the process which results in a mineralised fossil, have been difficult to nail down. This is at least in part because fossilisation is not a single process. A fossil can come about through many different routes, but always involves a set of unlikely conditions and complicated geochemistry. This is well shown by Thomson (2005). We would like to fully understand this process as our knowledge of evolution stands on the foundations of the fossil record. Studying the mechanism of taphonomy is in itself a recent aspect of palaeontology and one which is intimately associated with the geology of the land. It is this linking of conditions and geology which has resulted in such large and high‐yielding fossil beds as are found in China, Mongolia and the USA.

      It is easy to understand that without a process of fossilisation, there would be no fossils and so we could only speculate, devoid of evidence, as to what had lived and breathed on our planet in bygone aeons. In fact, under such circumstances, we may not even consider that there had been species before those that are currently extant. Without the existence of fossils we would have no easily recognised method of aligning the age of the Earth to reality. This would render myths about God creating the planet in seven days and its associated fantasies, difficult to gainsay. However, we do have fossils and so we do recognise the age of the earth as much greater than we can easily comprehend.

It is the human scale of perception of time which made it easy to persuade people that the creation of the Earth happened only a few thousand years ago. By having a version of events which was just about on a conceivable time scale, it made the whole story plausible, which having to think in millions of years was not. Even so, this Biblical explanation involves a period of time which is almost unimaginable when compared to the lifetime of an individual or the social memory of a family. Nonetheless, it is much shorter than thousands of millions of years, which in truth is a scale that really has no meaning to the individual, or even in terms of the life cycle of a species. Species come and go, the average lifespan of a mammalian species seems to be between one and two million years (Mace 1998). This is why palaeontology is so close to geology, it extends so far back in time that only the rocks tell the story, but it is pivotal in the study of the origin and evolution of life.

      Part of the modern fascination with fossils stems from the same conundrum with which they were first approached; how can an organic, living being, be converted to rock? The idea that a fossil was the imprint of a living thing made into stone did not gain broad traction within the general population until the nineteenth century, even though it had been voiced prior to this. It is also true that the essential problem of admitting fossils as being mortal remains transmuted into stone was putting science into direct conflict with the Church.

      Most early naturalists, and nascent palaeontologists, had gained a classical education, many having been ordained clerics, so there was a long history of reluctance on their part to accept the idea of fossils as organic remains. Such an idea would be in direct conflict with their faith, or at least their education. There was, as a consequence, a long period of published ideas that tried very hard to roll the idea of fossils into a corner where they could be explained away as artefacts or accidental productions of nature, but certainly not the remnants of long extinct species. These arguments were used by Plot (1705) to explain many of the fossils that he found in Oxfordshire.

      A change in general attitude towards the nature of fossils took place in the nineteenth century with the parting of the ways between Romanticism and science. Romanticism found its place in the self‐indulgent imagination of literature, while the educated imagination of science stood against the idea of assumptions, like those promulgated by religion. It was the broadly untestable ideas of history, which had stood as untested mythical explanations for centuries that were going to yield to the new inquisition of scientific thought. Scientific investigation of fossil material was fuelled by a need to build a consistent picture of the world, which would always be open to challenge as new information arose, but a picture which by its very nature would allow for predictions that could be tested. This was exemplified by the work of Lyell (1832).

Just as we sometimes forget that nobody has seen a living dinosaur, it is also true that nobody has seen the process of fossilisation, that extraordinary series of changes from soft organic to immutable solid. The very indestructibility of stone was part and parcel of the original problem of thinking that fossils could be plant or animal in origin. Even when they were clearly recognised as biological in origin, the questions that were raised were difficult to answer, indeed, they were in some quarters seen as heretical even to ask. The questions immediately associated with fossils were not necessarily at odds with the Biblical story of genesis. For example, if fossils were the remains of animals which were obviously akin to sea animals, how could they be found at the tops of mountains and among cliffs? Several different suggestions were made, the two extremes being that the sea level had dropped (Leonardo Da Vinci, Notebooks 1880) or that earthquakes had raised the mountains (Robert Hooke 1668). Such ideas only held for those species which were obviously marine, problems with skeletons of creatures that ostensibly walked the earth were so mired in difficulty that for the most part such skeletal remains were ignored or put down as unusual rock formations.

      Besides the positioning of fossils, there was another problem that vexed both the Church and philosophers. If, as seemed likely, fossils were products of the organic world, both of plant and animal material, they were not like anything currently known. So if they did represent animals or plants, then there would have to be a concept of extinction. This flew in the face of the Bible where creation had taken place as a representation of perfection, and there were neither deletions nor additions of plants or animals possible. As a by‐product of this logic, neither were those species that were found, capable of change. If there were extinctions or additions to creation, but most notably extinctions, the implication was that God had made a mistake and had a few attempts at creation before coming up with the final version. Some of this could be partially explained away by assuming that species changed over time. This possibility of a mutable species required a certain flexibility in ecclesiastical interpretation, which was not always possible in some churches.

      Even assuming some ability to change, the radical nature of some fossils was difficult to explain in this way. They were just so different, accepting that they had a biological origin would require a big step towards accepting extinction as a real possibility. So another attempt at explaining the animals found fossilised, without treading on ecclesiastical toes, was to suggest that fossils represented species which had died in that locality, but were still extant elsewhere on the planet, or perhaps they had been washed there during the Flood. It was not so difficult to entertain the idea of a species still being alive elsewhere as the planet was ostensibly a much bigger place than it is now. Travel was difficult and slow, indeed there were many areas which remained unexplored until well into the twentieth century. To the explorers of the eighteenth and nineteenth centuries, the immense scale of the Earth left the feeling that there were hiding places where these species, known only from fossils, could be found.

There is one example of this strange phenomenon of a species being known from fossilised remains and then being rediscovered