Fossils, geology and minerals. The highly acclaimed international earth science magazine with over 600 articles and book reviews.
I sat down to read this over Christmas and what a good read it turned out to be. The appropriate word is ‘eclectic’ – because Measures for Measure is written for all us with an interest in the industrial history of Great Britain, and its impact on the landscape, economy, social history and culture. It’s a great read as it dots about linking places and ideas together, with the link always being the geology.
Stephen K Donovan (The Netherlands) This is the first of six articles that will introduce the geology of the Antillean island of Barbados. It is an expanded and more detailed guide derived from two earlier publications (Donovan & Harper, 2005, 2009). The structure of the guide will include a summary of the geology of the island (in this part) and five, one-day field excursions for the geologically-biased tourist. These excursions will introduce the stratigraphy, structure and geological history of Barbados (Figs. 1 and 2), a small Antillean island shaped like a contorted teardrop, about 34km long by 24km at its widest. Fig. 1. The principal features of the geological history of Barbados summarised in a single section at Spring Bay, parish of St. Phillip, on the southeast coast. Professor David Harper (University of Copenhagen) is looking northwest, towards Ragged Point (Fig. 2) and admiring the angular unconformity between the allochthonous Palaeogene basal complex (=Scotland Beds) and the overlying autochthonous bedded limestones of the Pleistocene Coral Rock. A visitor to the island, who wants to undertake fieldwork, should hire a car. The only other reliable forms of transport are bus and taxi. While cheap, buses tend to stick to the main routes, particularly in the countryside. However, the size of the island means that localities are rarely more than a few kilometres from a bus stop. If money is no object, a taxi driver will be happy to drop you at a site in the morning and collect you at a … Read More
Byron Blessed (UK) As many of us know, a good day’s fossil hunting rarely stops when we leave the beach. However, many people do not know what to do with a fossil once they’ve found it. So, here are a few pointers in the art of fossil preparation. This article will not only outline what equipment you will need but will also give you general guidelines on how to use it. Fig. 1. The various stages of prep-work. Nautilusastercoides, found in the Upper Lias, Sandsend,near Whitby in North Yorkshire, UK. The first thing that any fossil preparator needs (and it isn’t something you can buy) is a lot of patience. The second thing you need is … a lot of patience! This cannot be stressed enough. Fossil preparation is a long, sometimes boring and laborious process and it is all too easy to damage specimens by being too hasty! It must also be noted that fossil preparation is not something that can easily and successfully be taken up overnight. Most of the best preparators have been in the business for decades. To think that you can immediately match their skills over night is naïve to say the least. Like any good hobby or job, practice makes perfect. In addition, it can be very costly to get all the right kit so this can become an expensive hobby. Washing specimens under the tap is a good, first step and will reveal hidden detail by removing unwanted mud and sand. Many clays … Read More
Paul Pursglove (UK) Take a close look at the three teeth labelled A, B and C in Fig. 1. All of these teeth could have been sold by unscrupulous fossil dealers as pterosaur teeth. So, which is the real pterosaur tooth? Pterosaur teeth are very rare fossils and they tend to be difficult to identify in isolation. However, they do command a high price to a collector. Most people who research pterosaurs will take time to study the teeth and to compare them with reference collections and scientific papers which are held in repositories at universities and major museums. So let us look at some of the general rules for identifying the teeth of pterosaurs. Fig. 1. What teeth are these? Triassic pterosaurs These little beasties are as rare as it gets. They are only known from a few sites worldwide, and the major finds come from the Zorzino Limestone of Cene, near Bergamo in Italy and from the Preon Valley. Other isolated specimens are known from Greenland, Luxembourg, Austria and Texas. There is also a speculative specimen from the Rhaetic bone beds in the UK. Most of these pterosaurs have three cusped teeth which are very distinctive. I am not aware of any Triassic pterosaur teeth in private collections. Jurassic pterosaurs These pterosaurs are more numerous, but tend to be predominated by Dimorphodon, Pterodactylus or Rhamphorhynchus-like specimens. Rhamphorhynchus is a good example of the pterosaurs that have long dagger-like teeth; several other species have very similar teeth, which can occasionally … Read More
If you, like me, spend much of your palaeontological time collecting Jurassic and Cretaceous cephalopods in the south of the UK (ammonites, belemnites and nautiluses), while dabbling with some Silurian orthocones in Shropshire, you will be delighted at the number of books being published recently about this fascinating group of animals.
David Mayhew (The Netherlands) When you walk through the countryside,youwill not often come across a vole. However, they are present in most habitats and are one of the most successful groups of small mammals, widely distributed in both Eurasia and North America. Broadly speaking, Voles are blunt- nosed, short-eared, mouse-like rodents and many of them are specialised for burrowing. They can eat hard vegetation such as grasses that are very abrasive due to the presence of silica spicules. Therefore, many species of voles haveevolvedcontinuously growing cheek teeth (that consist of molar teeth: three upper and three lower) as well as the continuously- growing incisors that are typical of rodents. Finding fossil remains of voles This evolution took place largely in the last three million years.For this reason, fossil remains of voles are very useful for helping us unravel the stratigraphy of deposits from the Pliocene and Pleistocene periods. And, as you can see from the photographs, they are beautiful objects in their ownright. We are talking here of quite small fossils, for example, the molar teeth are between 1 and 3mm in size. So, where and how are they found? Many, even thousands of specimens, can be found in cave and fissure deposits, such as Foxholes at High Wheeldon in Derbyshire. Often, such localities have no stratigraphic context other than the fauna contained in the sediments. However, the material may be very complete (skulls, lower jaws and limb bones). Fig. 1. Remains of vole Microtus sp. from Foxholes cave, High … Read More
Joe Shimmin (UK) The beauty and variety of the microfossils of Folkestone’s Gault Clay cliffs has amazed me ever since I was about 14 years old. At about this time, I had the good fortune to see some samples sent to me by Jim Craig, who I had met at the site. These microfossils roused in me such enduring enthusiasm that I eventually wrote an article entitled Marvellous microfossils (Part 1): Collecting Microfossils from Folkestone on how to process Gault Clay to obtain. This is the second article on this topic. Apart from the fact that the Forams, Ostracods and other microfossils found in the residue left by wet- sieving Gault Clay are interesting and unusual, in themselves it is also a bonus that there are vastly more of these fossils, in terms of numbers, to be found than the larger fossils that people usually go there to collect. If you collected hundreds of these larger fossils from a site in one go, you might be seen to be selfishly depriving other collectors of the opportunity to collect some for themselves. However, within 1kg of Gault Clay, there are literally thousands of microfossils. Therefore, removing a few kilograms of Clay from the site will do no damage whatsoever. So, within reason, you can build up a huge collection of a vast variety of microfossils with minimal impact on the site. These reasons have led me from writing the article referred to above to attempting to write a small book (or, … Read More
This book is truly sumptuous, and yet is also a comprehensive discussion of William Smith’s maps (including the revolutionary ‘A Delineation of the Strata of England and Wales, with part of Scotland’) and career. It is beautifully produced, printed on quality paper and the full colour illustrations are outstanding.
Joe Shimmin (UK) The Gault Clay outcrop, at Folkestone in Kent, is a wonderful place to find all manner of fossils. Over 100 species of ammonite have been found and there are also barnacles, belemnites, bones (reptile and fish), coprolites, corals, crinoid pieces, crabs, crocodile teeth, fish teeth, gastropods, (deep breath) nautiluses, ccaphopods, shark teeth, vertebrae (bony fish, shark and, occasionally, reptile), worm tubes and more. These fossils can be found in the clay cliffs and also at the base of the cliffs, washed out from above. But there are other fossils to be found at Folkestone that are less conspicuous. Fig. 1. The cliffs at Folkestone. An individual, who is new to the site, may be forgiven for thinking that the larger fossils are all that Folkestone has to offer. If this were so, it would still be a fantastic location. The fact is, however, that this is not the case. Folkestone’s Gault Clay also has a rich and varied, beautifully preserved, microfossil fauna. Fig. 2. Enlarged images of microfossils from the Gault Clay at Folkestone. Microfossils are trickier to find and collect than their larger counterparts. They are hard to see, often quite fragile and difficult to handle. However, with a small amount of perseverance, along with a good technique and a few pieces of apparatus, anyone will be able find hundreds of these beautiful and intricate fossils and, in no time, build up quite a collection. While on a fossil hunting trip to Folkestone, it is well … Read More
Jon Trevelyan (UK) In Issue 60 of Deposits, I restarted my occasional series on UK geological museum with a visit to the Booth Museum in Brighton (see Geology museums of Britain: The Booth Museum of Natural History, Brighton). Having more time on my hands than I would like during the Covid-19 lockdown, I got to thinking about a recent visit I made to the Museum of London in the Barbican in the City of London. I expect that most people would not link this excellent museum to anything geological, but they would be wrong. In fact, there are many exhibits from the prehistory of the capital and these include fossils of animals that lived in the region and stone tools from our ancient ancestors, who shared the area (Figs. 1 and 2). Fig. 1. A somewhat demonic looking auroch (Bos primigenius), which is an extinct species of large, wild cattle. These were domestic during the Neolithic Revolution, such that modern breeds share characteristics of the aurochs. Fig. 2. Flint tools found at Swanscombe. In fact, the museum’s oldest items date back to when London was tundra and the local population would fit into one of its iconic double-decker buses. During these times, there were several different species of humans occupying the Thames Valley, firstly as hunter gatherers and only later creating fixed settlements. Human and animal species roamed the open steppe-tundra, until their final disappearance about 30,000 years ago; and Neanderthal groups probably shared the valley with modern humans. And … Read More
Carl Mehling (USA) Things aren’t always what they seem. The fluidity of information and the frailties of human memory allow for a lot of corruption. Innocent assumptions are made. Sloppy mistakes take place. Unforeseeable accidents occur. And deliberate subterfuge is always there as an option when these others fail. Throw a little time at them and mis- and disinformation get lithified, entrenching them in the human psyche and culture. Fighting for accuracy is a continuous battle. A wing and a prayer Once almost considered throw-away parts of the bird, chicken wings have soared to unimaginable heights since their transformation into ubiquitous bar food in the 60s. Buffalo wings are so absurdly popular in the US that possibly-calculated rumours often circulate that a wing drought is coming, causing the requisite panic. Sports bars riot over this dearth, prompting half-serious suggestions of breeding chickens with more than the pathetic pair that their lineage has provided. Anything this popular inevitably spawns feuds over priority: Who gets to claim bragging rights for such a powerful, lasting and lucrative phenomenon? Fig. 1. Were the origins of Buffalo Wings in a science pub or a brew pub? This certainly happened with Buffalo wings. I’ll spare you the gory details, but although hard to prove definitively, most have settled on the idea that the Anchor Bar in Buffalo, NY began this tangy trend in 1964. However, as it turns out, it can be demonstrated that the origin of buffalo wings actually happened elsewhere, and in 1962. Or, … Read More
Dr Paul D Taylor (UK) Fossil collectors often overlook, or worse discard, bryozoans. There are several reasons: some bryozoans are small and not easily spotted in the field, others are mistaken for non-descript sponges or algae, while bryozoans cemented to the surfaces of other fossils can be cursed for detracting from the value of the main fossil. But bryozoans are fascinating fossils in their own right and ought not to be ignored. Bryozoans are a morphologically varied phylum of colonial invertebrates. The myriad of colony-forms they exhibit reflect adaptations that evolved to allow them to prosper as immobile colonial animals living on the seabed and feeding on passing plankton (Taylor, 2020). The majority of the more than 6,000 bryozoan species living today possess resistant skeletons of calcium carbonate, and the calcareous skeletons of fossil bryozoans are abundant globally in rocks ranging back to the Early Ordovician, some 480 million years. Fossil bryozoans in Britain occur in marine sedimentary rocks from every post-Cambrian geological period except the Triassic. Ordovician bryozoans can be found in the Welsh Borderlands and in southern Scotland, Silurian bryozoans in the West Midlands and Shropshire, Devonian bryozoans in Devon, Carboniferous bryozoans in the Pennines and other places where the Carboniferous Limestone outcrops, and Permian bryozoans in the Magnesian Limestone of northeast England. Previous contributions to Deposits have described bryozoans from the Chalk of Late Cretaceous age (Taylor, 2018) and the Pliocene Coralline Crag of Suffolk (Taylor and Milne, 2009). Here, I focus on British Jurassic bryozoans. Jurassic … Read More
Mary Anning was clearly one of the most significant characters of eighteenth century science and possibly of all time, particularly in the realm of palaeontology. I am not sure that she is quite as unknown (certainly in the UK) as the American author this excellent little biography claims, but she certainly should be better known.
Dr Robert Sturm Over the last few decades, local amateur collectors, as well as professional palaeontologists, have collected a large number of fossils from quarries and sandpits on the northern margin of the Central European Alps. With the help of these marine and terrestrial fossils, it has been possible to reconstruct a picture of the animal life in the early Tertiary (about 50Ma). Interestingly, many animals that lived in these ancient tropical habitats can still be found in the oceans and on the coasts today. Main geological characteristics of the area Fig 1. Upper image: geological map of the Northern Alpine Margin and the alpine foreland near Salzburg in Austria. Lower image: north-south profile through the northern alpine lithology and the alpine foreland clearly indicating that single geological units are superimposed from south to north as a result of the movement of the African plate northwards. As you can see from the map in Fig. 1, the geology of the northern Alpine margin can be subdivided into three main, east-west striking units: The Flysch Zone (green) is situated directly north of the limestone Alps, the exposed part of which reaches a width of up to 20km. The grey marls and sandstones belonging to this unit were deposited in a deep, oceanic basin during the Cretaceous (144 to 65Ma) and measure more than 3,500m in thickness. In the south, the Flysch Zone was successively superimposed on by the Northern Limestone Alps.The Helvetic zone (violet) borders on the Flysch Zone in the … Read More
Dr Robert Sturm As a result of their great diversity in shape and long-lasting occurrence in earth history (from the Devonian to the Cretaceous), ammonites are equally fascinating objects for the professional and amateur palaeontologist. By definition, ammonites exclusively comprise a group of extinct marine cephalopods that, according to the present store of knowledge, include about 1,500 genera and between 30,000 and 40,000 species. The shell size of adult animals ranged from a few centimetres to two metres in the case of Parapuzosia seppenradensis (Lehmann, 1981; Monks and Palmer, 2002). The introduction of ammonites into zoological systematics was carried out by Carl Alfred von Zittel in 1884, who defined the sub-class ‘Ammonoidea’. This unconventional term dates back to the first century AD, when the elder Pliny interpreted these fossils as horns of the ancient Egyptian god Amun. Since the petrified shells represent the most important relics of ammonites, information on their biology and anatomy is characterised by a number of uncertainties. For example, it is assumed that these cephalopods only possessed a small number of tentacles (eight to ten) and also an ink pouch, or bursa, for protection against natural enemies. Most species lived in a water depth of between 50m and 250m, where they mainly fed on crustaceans, foraminifers, and ostracods. Ammonites were also characterised by sexual dimorphism – the smaller individuals were males and the larger ones were females. Palaeontological determination of single species is chiefly based on the shape, size, sculpture and torsion of the shell, as … Read More
Dean R Lomax (UK) Introduction Ichthyosaurs are extinct marine reptiles that superficially resemble dolphins and sharks, but are neither. They are most definitely not ‘swimming dinosaurs’. In fact, they were fully aquatic marine tetrapods that lived in the seas, while their more famous counterparts – the dinosaurs – roamed the land. They achieved a worldwide distribution and remains have been discovered from the late Early Triassic to the early Late Cretaceous, and hundreds of species have been described (McGowan and Motani, 2003). The coastal town of Lyme Regis, situated on the Dorset coast, is often seen as the birthplace of ichthyosaurs. Many ichthyosaurs were collected from here during the early nineteenth century and were first brought to the attention of the scientific world by a fantastic young woman called Mary Anning (see below). The focus of this article is based on the most famous ichthyosaur genus, Ichthyosaurus, which lends its name to the group. The first species, I. communis, was described in 1821; the second, I. breviceps, was described in 1881; and the third, I. conybeari, was described in 1888. Since then, lots of ‘Ichthyosaurus’ have been described and all have since been found to represent distinct ichthyosaur genera and species, until now. No-body-saurus In 2008, I began researching the collections of my hometown museum, Doncaster Museum & Art Gallery. One specimen, the key ichthyosaur of this study, was shown to me as “an exceptional cast” (this was as part of an exhibition I created at the museum; see my … Read More
Dean R Lomax (UK) A ‘big’ discovery In 2002, a wonderful discovery of a 9.7m-long trackway (ichnofossil) with the tracemaker (a horseshoe crab) preserved was made in a quarry near the village of Wintershof, north of the town of Eichstätt in Bavaria, Southern Germany (Fig. 1). Specifically, the specimen was collected from the Solnhofen Lithographic Limestones, Eichstätt Formation (Solnhofen Group), Hybonotum Zone, Riedense Subzone from the Late Jurassic (Tithonian). Fossils from Eichstätt are often confusingly thought to be from the area of ‘Solnhofen’, with the Solnhofen area being a world renowned Lagerstätte. Many exceptionally well-preserved fossil specimens have been collected from that area, including the famous fossils of Archaeopteryx. Fig. 1. Locality map of the fossil bearing localities within the Solnhofen area. Note the areas of Eichstätt and Wintershof, the locality of the trackway (WDC CSG-233). (Reproduced from Lomax and Racay, 2012.) However, many people are unaware that there are numerous localities that surround the area of Solnhofen, which yield many of the fossils from this famous geological unit. It has been suggested that several of the fossils found within the rocks originally laid down in the Solnhofen lagoons (which were part of an archipelago) are the result of mass storm events, during which organisms from the nearby Tethys Ocean were thrust into these anoxic lagoons during heavy storms. In many cases this was the beginning of the end. The horseshoe crab that produced this trackway was identified as Mesolimulus walchi. The taxon is fairly well recorded within the limestones … Read More
Dr Robert Sturm (Austria) Unlike the British Isles, which contain large swathes of Palaeozoic rocks, Central Europe only features sporadic rock types belonging to this early geological era. Among the most salient geological terrains entirely or partially from the Palaeozoic are the Bohemian Massif, the Central Plateau in France, the Ardennes in Belgium and the Black Forrest in Germany. Within the alpine mountain belt, the frequency of Palaeozoic rock formations is even less, with such rock deposits being limited to the Greywacke Zone in the Central Alps, the Palaeozoic lithologies exposed around the city of Graz, the Gurktal nappe and the Carnic region/Karawanken in the Southern Alps. In this article, I will discuss some important Palaeozoic index fossils from the Carnic region that have been found by Austrian palaeontologists over the last few decades. Geology of the Carnian region in the Southern Alps – a brief overview When visiting the Carnic region in the early nineteenth century, the famous natural scientist, Leopold von Buch, expressed his fascination of the virgin landscape he came across with the statement that it was “a fully unknown area [that] has to be discovered and comprehensively described”. Since then, the Carnic region has acquired a high reputation among geologists and palaeontologists in Europe and, indeed, all over the world, because it represents an outstanding ‘picture-book’ containing 500myrs of earth history. In this area, there is a considerable amount of evidence of specific sections of this long period of geological time and especially for those prehistoric … Read More
Scotland has been the source of many important fossil discoveries, from the first ever soft body parts of the conodont animal, to Devonian fishes and early tetrapods. Yet, there has been little published for the popular market on Scottish palaeontology.
David M Martill (UK) After several gruelling years of working in the sticky wet Jurassic clay pits of the Peterborough district for their gigantic marine reptiles and even more massive fishes, it was a refreshing change to fly south and investigate the sun-baked Caatinga of South America. The Chapada do Araripe, on the borders of the Brazilian states of Ceará, Pernambuco and Piaui, had always fascinated me (Fig. 1). Fig. 1a (left). A map showing the location of the Chapada do Araripe in the northeast of Brazil. Fig. 1b (above). Detail of the Chapada do Araripe. This is one of the most important sites in the world for Cretaceous Gondwanan fossil fauna and flora. I had seen specimens of the fabulous fossil fishes (I hope you like the alliteration) in limestone concretions (Fig. 2) that kept turning up in European fossil shops, but what had really caught my eye was a short letter to the scientific journal Nature that described fossil ostracods from those very same concretion horizons. Fig. 2. A typical concretion from the Santana Formation, with a not so typical fish. This is one of the rare fossil rays. I am not an aficionado of ostracods: who is? They mostly look like small baked beans, and it is so tedious trying to mount them on stubs so that you can see them under the electron microscope. No, it was the remarkable quality of their preservation that caught my eye. The specimens in question were described by Ray Bate, … Read More
This is a lovely little book and something of a departure for Dr Dean Lomax, who, these days is more often seen up to his elbows in ichthyosaur remains. However, this fun little book is rather different. Dean (and ably helped by the artwork of Mike Love) has created a full-colour popup book covering the ancestors of many of our favourite pets.
This is a lovely book – a glorious mixture of a beautiful coffee-table book and an academic treatise of the highest quality. But why microfossils? What is it about them that can create such strong feelings?
Jens Lehmann (Germany) Thick-shelled oysters of the species Pycnodonte (Phygraea) vesiculare (Lamarck, 1806) are among the most common fossils of the late Cretaceous period of Europe. They are also known as “thick-shelled mussels” in the popular wisdom and the reason for this name is obvious when you have a look at a typical example (Fig. 1). Fig. 1. A large specimen of Pycnodonte (Phygraea) vesiculare, as typically occurring in the latest Cretaceous of Europe. From the Campanian of Haldem near Lemförde in Germany. This is an historically important specimen, because it belongs to the reference material of Arnold (1968) from this famous locality, which has produced many type specimens of fossils. GSUB L559. They can be seen in many museums, but, even more often, they are encountered during walks along the beaches under the chalk cliffs of England or around the Baltic Sea in continental Europe. A famous locality is the island of Rügen in Germany, where tourists can easily spot them (Fig. 2). Fig. 2. Collecting Pycnodonte from Late Cretaceous (early Maastrichtian) chalks is popular among tourists on the Isle of Rügen (Promoisel pit near Saßnitz) in northeastern Germany. (Photo by Martin Krogmann, 2014.) Therefore, it is not surprising that this extinct oyster species was selected as “Fossil of the Year” 2017 by the German Palaeontological Society (Paläontologische Gesellschaft) due to its ease of recognition (Kutscher 2017). Further reasons for the vote include its scientific and scientific-historical significance. This is the second time the society voted for a fossil … Read More
Jens Lehmann (Germany) The recent find of a big slab of Early Cretaceous lumachelle limestone of the Wealden facies containing a bone (Figs. 1 and 2) made for a time-consuming and technically ambitious preparation process. (Lumachelle limestone is a compact limestone or marble containing fragments of shells, encrinites and other fossils, which are sometimes iridescent, and display a variety of brilliant colours.) The specimen looked disappointing at first sight, but the end result made the hard work worthwhile, as I discuss below. Indeed, the following is intended as an example of the technical aspects of palaeontology, which are too often forgotten or ignored. The specimen was discovered in a loose, but very heavy slab on the beach. Therefore, efforts were made to reduce the size of the rock in the field to make it easier to carry, but, unfortunately, it broke into two pieces (Figs. 1 and 2). Fig. 1. A bone in a limestone from the Early Cretaceous (Barremian, Wealden facies), broken while preparing the slab in the field. Fig. 2. Reverse side of the limestone slab, with masses of freshwater bivalves making up most of the boulder. The original surface of the bone was completely worn – with no details preserved (Fig. 3A) and therefore a transfer preparation had to be planned. On the other side, the cross section (Fig. 3B) gave me a pretty good idea of the shape of the bone before preparation and the exact thickness of the rock that would have to be removed … Read More
Jens Lehmann (Germany) Since 2008, the largest palaeontological association in Germany – the Paläontologische Gesellschaft – has awarded the crown for ‘Fossil of the Year’ for fossils that are of special scientific interest or that are commonplace in that they are on display in many institutions. A ‘Fossil of the year’ can also be easy to collect species, encountered by many amateur enthusiasts. Among others, the largest ammonite in the world in the museum of Münster and the spectacular dinosaur skeleton of Brachiosaurus from East Africa in Berlin have won the title. This is the fifth time the award has been given, but is actually the first time the crown has been given to a fossil species and not to an individual fossil find. This year’s title went to Arthropleura armata, a remarkable arthropod species resembling recent millipedes and centipedes (Fig. 1). However, details of the phylogenetic relationships of the order Arthropleurida to millipedes are still debated (for example, Krauss, 2003a, b). And the arthropleurids reached significantly larger dimensions, with a total length of more than two metres (Fig. 1) and, therefore, are the largest arthropods ever to have lived on land. The first occurrence of the genus Arthropleura dates back into the period of the massive coal swamps of the late Carboniferous and they became extinct at the end of the early Permian – during the first phase of the supercontinent Pangaea. Arthropleura lived 280 to 340mya, but related arthropleurids (order Eoarthropleurida) continued to exist into the Silurian. Fig. … Read More
Jens Lehmann (Germany) Plate tectonics drove the continent-continent collision of Euramerica and Gondwana, roughly 280 to 380mya. This mountain-building phase of the late Palaeozoic era is referred to as the Variscan Orogeny and eventually formed the supercontinent Pangaea. This was largely complete by the end of the Carboniferous and many of today’s secondary mountains in Europe are ascribed to the Variscan phase. In the UK, this event formed a couple of spectacular places for geotourism at the boundary between Devon and Cornwall. When visiting southwest England, you should not miss these spots – they are surely among the most impressive places in the world showing the effects of tectonics. A tiny settlement but tremendous in geology A tiny settlement on Cornwall’s coast gives the name for surely the most famous spot for folded sedimentary rocks in the UK – Millook Haven. A narrow, winding road leads down the hillside, with a gradient of 30° (Fig. 1). Fig. 1. At the top of the winding road down to Millook Haven. But, after surviving the journey downhill, you are rewarded by a cliff with spectacularly folded Carboniferous sediments (Fig. 2). Fig. 2. A group of geology students visiting the spectacular Millook Haven cliffs. On a global scale, coal swamps are typical of the late Carboniferous period. However, in Cornwall and Devon, no economically viable coal was deposited. In southwest England, alternating sand- and claystones, which had been transported by submarine currents with material mainly in suspension, were formed in an environment far … Read More
John P Green (UK) The Ampthill Clay Formation of the UK, of Late Jurassic (Oxfordian) age, represents a series of highly fossiliferous marine mudstones that form part of the Ancholme Clay Group in North Lincolnshire (Gaunt et al, 1992); but are almost unexposed in the county other than at an excellent exposure of the Ringsteadia pseudocordata zone at South Ferriby Quarry (SE 992204). Therefore, this shortage of natural exposures means that any information, which can be obtained from other exposures in this county, is of the utmost significance. Minor stream exposures at Kingerby Beck, North Owersby in North Lincolnshire (TF 0519 9340) have revealed a rich and well-preserved fossil fauna. These minor exposures have been placed by Gaunt et al (1992) within the Amoeboceras glosense zone, therefore lying at a differing stratigraphical horizon to the South Ferriby Quarry. Also, in contrast to the latter locality, the fossils exhibit a much higher degree of preservation and are therefore easier to collect. Fig. 1. Kingerby Beck, North Owersby. Minor exposures of the Jurassic Ampthill Clay. Unfortunately, biostratigraphical bed-by-bed collecting is largely impractical at Kingerby Beck, due mainly to the very minor nature of the exposures; indeed, the majority of fossils have been collected from patches of clay exposed on the stream bed. The Ampthill Clay Formation, where exposed, is present as undifferentiated pale grey mudstones, with scattered calcareous concretions. It is these that are the major source of the prolific and well-preserved fossil faunas, particularly ammonites. Some of these concretions are very … Read More
John P Green (UK) The large, disused quarry at North Ormsby [O.S. grid ref. TF2893], north of Louth in Lincolnshire, displays an important sequence of beds of the Burnham Chalk Formation (Upper Cretaceous, Upper Turonian stage) and, at present, constitutes the best exposure of the beds in the county. Similar beds exposed at Ulceby Vale Pit [TA104133] in North Lincolnshire have described in terms of both stratigraphy and palaeontology, by Wood (1992) and, more recently, by Hildreth (1999, and in press). Fig. 1. North Ormsby disused quarry; an important sequence of beds of the Burnham Chalk Formation. The North Ormsby section was measured and described in stratigraphical terms by Wood and Smith (1978), although little information on the macrofauna was published. Hill (1902) was the first to identify the S. plana biozone of the Burnham Chalk Formation in this area, and Rowe (1929) provided an admirable macrofaunal list in his account. Therefore, my aim is to build on the work of previous authors, and place the recorded macrofossils in a stratigraphical context. In addition, Wood and Smith (1978) established important flint and marl marker horizons for the chalk of Lincolnshire and Yorkshire, and these shall be referred to in this account. Fig. 2. Closeup of the Burnham Chalk Formation. The Burnham Chalk, as exposed at this locality, consists in general terms of thick bedded chalk, interbedded with marl seams and marl layers, and beds of predominantly tabular and semi-tabular flint bands. About halfway up the sequence, above the level of … Read More
I don’t normally review BGS memoirs – they are excellent publications, but largely written for the professional or the seriously committed amateur geologist. (I have to admit to owning several, which cover my favourite fossil collecting areas of the UK.) However, this is one ‘Special Memoir’ that I am quite willing to make an exception for.
John P Green (UK) The Early Cretaceous succession in Lincolnshire consists of a series of shallow water marine sandstones, ironstones, clays and limestones, not unlike those deposited elsewhere in the UK during early Jurassic times. In the north of the county, at Nettleton Hill, near the village of Nettleton, minor exposures of the Claxby Ironstone Formation are present. Fig. 1. Nettleton Hill, showing former site of workings for Spilsby Sandstone and the overlying Claxby Ironstone, now restored. This deposit, approximately 5.7m thick, rests unconformably on the eroded Late Jurassic Spilsby Sandstone Formation of Volgian age. The age of the ironstone ranges from the Lower Valanginian to the Lower Hauterivian stage, and is of particular interest due to the ammonite and belemnite faunas it contains. My studies over a number of years have brought to light a series of cephalopod faunas that are also prevalent in Speeton, East Yorkshire, as well as northern and southern Europe. Prominent contributors to the study of the cephalopod faunas of this formation include Lamplugh (1918), Swinnerton (1935), Casey (1973), Wright (1975) and Kemper et al (1981). The ironstone is divided into two members: the Lower and Upper Claxby Ironstone Formations. Both these formations are characterised by a brown to purple clay matrix, rich in prominent iron ooliths, and which is highly fossiliferous. Excellent exposures were formerly present in opencast and deep mines around Nettleton (TF 1140 9868, TF 1164 9870). However, these sections are now unfortunately filled in. The current exposures at Nettleton Hill, while … Read More
