I took a short holiday recently and walked the coastal path from Sherringham to Cromer and along the way there is the sea view beach cafe in West Runton. It is a cafe that serves tea and coffee and ice cream but it also has a fossil museum. Most of the fossils have been found on the coastline of West Runton. So it was a contrast, walking the coastal path in the present day with people pushing dogs in those little buggies and seeing the sea stretch out for miles and climbing the Beeston Bump that is said to have been the base of black shuck: the mythical dog described by Abraham Fleming in 1577 as a strange and terrible wunder and a horrible-shaped thing, and at the cafe in display cases there are deer jaw bones that are double the size we would expect from a deer now, and a cast of the tibia from a Mammuthus trogontherii or steppe mammoth standing 83cm high and fascinating tube-shaped shells, basically the remains of a different land that stood in the same spot.
There is a scientific paper describing the excavations of the West Runton Mammoth that resulted in the tibia cast displayed in the cafe. The paper has photos taken in 1995 that show the sheer size of the bones that were found preserved. Lifting a Mammoth femur or a partial Mammoth skull and tusk of such a weight out of the ground involved coating them with plaster to keep them intact and noting exactly where they were retrieved in the sediment with a theodolite for angle measurement and to a granularity of within ten centimetres. The recording of the bone's positions in the ground was important as there had been previous excavations to coordinate with. In 1990 coastal erosion exposed an enormous pelvic bone at the West Runton cliff site, the paper describes a rapidly-improvised excavation where the pelvis proved both very heavy and much more fragile than it had first appeared, with the unfortunate result that it was recovered in many fragments. However a left astragalus or ankle bone was removed in it's entirety and the pelvis could be pieced together. Between 1991 and 1992 excavations recovered about twenty five percent of the skeleton including the mandible and several limb bones, vertebrae and ribs and the position of these finds in the ground were mapped using a simple line and offset technique. By 1995 archaeologists had together unearthed a near complete Mammoth skeleton, and recorded the positions of the bones as they were excavated as shown in this outline picture of the site.
A question arises of where did this Mammoth live? Figure one of this paper shows the mammoth excavation along with sediment analysis sites. The sediment analysis shows that there are signs of a subsidence through the site of the mammoth excavation and extending either side and running parallel with the modern cliff face. Within the depression there is evidence of a freshwater bed over a chalk base. The same paper on the sediment in the freshwater bed describes through a combination of the chemistry of the silts that turned to sedimentary rock and the accumulation of pollen within them, a picture of a fast flowing water with frequent flood events surrounded by grasses and sedges constituting a herb-rich grassland and that later the shelly sandy waters slowed to be stiller and surrounded by birch, pine, elm and alder trees which later gave way to a mixed oak forest. The plant life implies weather that the Freshwater Bed existed between known glacial cold climates.
The West Runton Freshwater Bed has been placed in time and relative to other geological settings in various studies. The first table in a paper which summarises the research carried out in the West Runton excavations of the 1990s contains the vertebrate fossils identified in the Freshwater Bed. Listed is a small mammal called Mimomys savini which is a now extinct genus of vole. This species is of interest as voles diversified over a relatively short geological time span and some voles undertook long-range, rapid migrations and so can be found in sites throughout the world. The details of the vole's teeth are related to it's evolutionary phase. This paper describes how Mimomys has rooted molars and evolved to a species of Arvicola with unrooted molars which is a defining step in time that links several geological sites that also have this vole as various stages of evolution. Figure one in this paper on the dental evolution of voles illustrates the increasingly intricate structure of the first lower molar of the Arvicolinae which is a further marker of evolution. A paper that summarises the Micromammals excavated from the Mammoth site at West Runton shows, along with many other small mammals photographs of jaw and teeth of the Mimomys savini. In the same paper the authors state that the presence of Mimomys savini defines an upper limit on the age of the West Runton site that is in the early part of Marine Isotope Stage 15, a time frame that started 621 thousand years ago.
The marine isotope stages can be understood as a measure of evaporation of ocean water as recorded in the different forms of oxygen present in the calcium carbonate shells of marine creatures in different layers of marine sediment. As described in this video Oxygen can exist in several atomic forms. Here we are concerned with Oxygen-16 which has a nucleus composed of eight protons and eight neutrons and the atomically heavier Oxygen-18 which has a nucleus structure of eight protons and ten neutrons. In extreme heat there is more ocean evaporation and as Oxygen-16 evaporates more readily than Oxygen-18 then there is a higher ratio of Oxygen-18 to Oxygen-16 in the remaining oceans and therefore in the shells of the marine creatures that live in it. Over years the shells build up with layers of sediment that when left undisturbed can be treated as a record of time and climate.
The age of fossils can also be estimated by the nature of the breakdown of protein, that is how the protein amino acids change over time. The shells of the freshwater gastropod Bithynia troschelii were recovered from the lower sediments of the West Runton Freshwater Bed. This paper found that various protein ageing signs can be found in different regions of the Bithynia troschelii shells. This paper concludes that it is too early, on the basis of the amino acid data alone, to attribute the West Runton Freshwater Bed to a particular stage in the marine oxygen isotope record, although a pre-MIS 13 age is indicated, which represents a time frame that started 524 thousand years ago.
There it is, something of how scientific papers describe a setting like the West Runton Freshwater Bed and a phenomena like a buried mammoth that would have been twice the size of a elephant today, with the details of the tiny jaws and teeth and evolution of a vole, the pollen and spores that would have floated in the air and the plants that created them and the weather that the plants would imply, the chemistry of long term ageing in oxygen isotope ratios in marine shells that helps placing events in time, lifting bones of such an enormous size out of the ground, coating and protecting them and noting exactly where they were placed. I like the intricate connection of one detail of this setting relating to another to give a clearer and clearer picture of time and place and of once living creatures, and that it all came from a holiday walk along a cliff to a cafe. I also like how similar the scientific method is to writing fiction which is about everything doing its work of explaining something else.