geology north america

Los Angeles’ fractured and filled landscape: a field trip to the sites

Deborah Painter (US) The Los Angeles Times reported on 5 April 2021 that a magnitude 3.3 earthquake struck around 4:15a.m., followed by a magnitude 4.4 quake 29 minutes later. Several aftershocks followed. Seismologist Lucy Jones of the Lucy Jones Center reported that two quakes were 19.31km deep, with an epicentre around Inglewood, in the Los Angeles Basin. She reported that the movement was thrust, probably not on any mapped fault. Californians scarcely even notice an earthquake of magnitude 3.3 at that depth below the surface. That magnitude on the Richter scale is in the order of a large truck driving rather close by, but probably not intense enough to awaken them from sleep at that hour of the morning while being intense enough to warrant a news item. If one believes television programmes and movies, “The Big One” is going to happen sometime in the near future and part of California is going to slide into the Pacific Ocean and vanish beneath the waves, much like an overloaded barge. The trope of the sinking Golden State gained popularity sometime in the 1960s and should have been thoroughly discredited by now. The film industry helped get this into the general public’s mind and the general public keeps it alive. However, it would be impossible for two reasons: Firstly, tectonics is not going to cause the land to subside as though it were a huge chunk of the crust precariously teetering over the edge of the continent. California is firmly attached to … Read More

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Plate tectonics (Part 4): More on the rock cycle

Helen Gould (UK) In Plate tectonics (Part 3): The rock cycle, I presented an overview of the relationship between the rock cycle and plate tectonics, and then went on to look more closely at igneous rocks. This time, I want to discuss sedimentary and metamorphic rocks, and review the occurrence of the rock cycle in the Solar System. Sedimentary rocks Sedimentary rocks, by contrast with igneous and metamorphic rocks, have no crystalline structure, being made up of little lumps of non-crystalline material derived from weathering other rocks. However, where they have been built up in horizontal layers, they may contain large-scale structures such as bedding. What are bedding planes? When sedimentary rocks deposited underwater (for example, limestones), they may be periodically exposed to the atmosphere due to tectonic uplift or a fall in sea level, perhaps because water is locked up on land as ice. The fact that it may take a thousand years to deposit a centimetre’s-worth of limestone places bedding planes into a context of millions of years. Fig. 1. Garnet micashist. Fig. 2. Garnet. Limestones are deposited in shallow seas, forming from the rain of billions of shells of sea animals onto the seafloor. Deposition stops if the area is exposed to the air and restarts when the sea covers it again, so a gap (bedding plane) forms. Many sedimentary rocks are laid down underwater and may contain bedding planes. In addition, the grain size, the fossils that are present and other lithological features all may vary … Read More

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Plate tectonics (Part 3): The rock cycle

Helen Gould (UK) What is the rock cycle? Usually, the first thing that budding geologists learn about rocks is that there are three kinds: igneous, sedimentary and metamorphic. These three major kinds are divided up into many different types of rock. For example, marble, slate and metaquartzite are all metamorphic rocks; basalt, granite, obsidian and andesite are all igneous rocks; and limestone, sandstone, clay and siltstone are all sedimentary rocks. What is a rock made of? Rocks are made of minerals. Therefore, particular combinations of minerals help us to identify rocks. Minerals are chemical compounds, consisting of chemical elements, which in turn are made of atomic particles. Who first thought of the rock cycle? James Hutton was the first geologist to propose a cycle of rock creation and change. In 1785, he gave a talk to the Scottish Geological Society in Edinburgh. In it, he suggested that rocks undergo processes that change them from one type of rock into another. He later developed the idea in his book, ‘Theory of the Earth with Proof and Illustrations’. He thought there was a relationship between the three basic rock types: igneous, sedimentary and metamorphic. We now know this is correct. Fig. 1. Agglomerate, Fig. 2. Andesite. However, it was not until this idea was set in a plate tectonics context that it really made sense to geologists. At about the same time, another Scotsman, James Hall, invented experimental geology. He demonstrated the crystallisation of basalt under slow-cooling conditions, and produced marble by … Read More

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What’s in a fossil name?

Dr Paul D Taylor (UK) There’s a small Cambrian trilobite (Fig. 1) that is collected in copious quantities from a site in the Wheeler Amphitheatre of Utah. Sold just as it is or mounted in jewellery, this trilobite lacks a common name and goes by its scientific name. In its fullest form, this is Elrathia kingii (Meek, 1870). But what exactly do the different parts of the name mean? How did Elrathia kingii – and other species of fossils – receive their names in the first place? And what are holotypes, lectotypes, neotypes and topotypes? In answering these and related questions, this article focuses on the procedures used by taxonomists when describing and naming living and fossil organisms. Fig. 1. The Cambrian trilobite species from Utah, now called Elrathia kingii (Meek, 1870), was originally named Conocoryphe kingii by Meek in 1870. Fifty-four years later, it was made the type species of the new genus, Elrathia by Walcott. Meek’s name is written in brackets because of this change in genus. Along with living organisms, the formal names of fossils employ the binomial system introduced by the Swedish naturalist, Carl Linnaeus in 1735. A genus name is followed by a species name, the latter sometimes referred to as the trivial name. Both are by convention always printed in italics, the genus name with a capital first letter and the species name with a lower case first letter. Unfortunately, newspapers all too often incorrectly print generic names with a lower case first letter. … Read More

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Plate tectonics (Part 2): A closer look

Helen Gould (UK) As we saw last time (Plate tectonics (Part 1): What are they?), the Earth is a pretty dynamic place, with tectonic plates moving about on the surface, driven by convection cells in the upper mantle. But producing a workable theory, which combined most of the observations of geological evidence, took years. It was known that the centres of continents were extremely old, and that some areas around the continental “cratons” didn’t seem to belong because they contained completely different types of rocks. Combining continental drift with seafloor spreading and mantle convection currents produced the idea of plate tectonics, and provided an explanation for the odd rocks on areas fringing some cratons. These “microplates” had come from other areas of the Earth, where different geological processes had produced different rock types. The role of density in recycling: oceanic and continental crust The physical features of the ocean basins and continental mountain ranges are known as the “crustal dichotomy” (splitting of the crust into two equal parts), and because these types of feature are essentially dissimilar, they have their own rock types. Basalt is the commonest rock both in the Solar System and on Earth, where it forms the ocean floor, along with various sedimentary rocks deposited underwater which make up another 5% of the total oceanic crust. Continents typically consist of coarse-grained rocks related to granites, which solidify below ground. Comparing similar-sized pieces of basalt and granite in the hand will establish obvious physical differences between them. Basalt’s … Read More

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Plate tectonics (Part 1): What are they?

Helen Gould (UK) What does “plate tectonics” really mean? The Earth’s surface bears about 20 plates, which are able, over millions of years, to move about on layers beneath the crust. Some of the surfaces of these plates consist of continental crust, some of oceanic crust, some both (Fig. 1). Fig. 1. Map of the tectonic plates of the Earth. Who came up with the idea? The idea didn’t develop overnight as a result of one person’s efforts. In 1915, Alfred Wegener suggested “continental drift”, in which the continents moved around on the Earth’s surface. Arthur Holmes later suggested continents could be moved by convection currents in the mantle, fuelled by the heat of radioactive decay. Harry Hess was an American geologist who came up with the idea of seafloor spreading. In the 1960s, J Tuzo Wilson developed the convection current idea further, proposed “hot spots” and “plates” and, in 1963, Fred Vine and Drummond Matthews proved the existence of seafloor spreading using “magnetic striping”. What proof is there that plate tectonics really exists? The fit of continents against each other, particularly Africa and South America, shows that they were once joined (Fig. 2). This branch of geology – palaeogeography – has led to the detection of several ancient supercontinents and oceans. Their existence is supported by matching similar geological features, such as ancient crystalline rocks and glaciated areas, in adjacent regions of South America and Africa, and North America and Europe. Two massive continents, which existed in the past, … Read More

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Smilodon family tree

Mike Thorn (UK) In his book, “Architects of Eternity: The New Science of Fossils”, Richard Corfield coins the term “reluctant palaeontologists”. He has in mind those chemists, biochemists and biologists who use the techniques and skills from their own disciplines to shed new light on our ideas about evolution. Ross Barnett, of the Department of Zoology at Oxford, might well be considered to be in this category. A biochemist by training, he has recently co-authored a paper on the DNA of three extinct cats which has helped to lay to rest some of the arguments about the feline family tree. Fig. 1. Smilodon skeleton. Ross came to Oxford in October 2002, to work on a PhD, after completing his biochemistry degree at Edinburgh. His supervisor, Professor Alan Cooper, was interested in cat genetics and had managed to raise funds to carry out research into the relationships of several extinct cats. In particular, there were questions about where the sabre-toothed cats, such as Smilodon and Homotherium, fitted in. Fig. 2. Ross Barnett in his office. As Ross explained: There has been a lot of study done on these animals. For example, there is a huge collection of thousands of individuals of Smilodon from Rancho Le Brea in Los Angeles, so they’ve been really well characterised from their morphology. What the palaeontologists had concluded from this was that there was a split at the base of the cat family tree between the group that goes on to form the sabre- tooths – … Read More

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BOOK REVIEWS england fossils geology palaeontology

Book review: Mortimer Forest Geology Trail, edited by Andrew Jenkinson and illustrated by Gillian Jenkinson and John Norton

This small, yet informative, booklet takes you on a four-mile walk to 13 sites and through 15 million years of Earth history. The Mortimer Forest Trail is a geology trail in Shropshire that is famous for its outstanding fossils and varied geology. The trail mostly examines Silurian formations such as the Wenlock and Ludlow series.

climate fossils palaeontology

Do mammoths warn of a climate crisis?

James O’Donoghue (UK) Did the destruction of forests by mammoths make the Pleistocene Ice Age even colder? It’s an extraordinary prospect. Yet, a leading fossil mammal expert thinks they did just that. Over many tens of thousands of years, mammoths and straight-tusked elephants ate their way through vast tracts of the world’s forests. Trees exert a buffering effect on global climate – take them out and face the prospect of hotter and colder extremes. Mammoths may have turned cool Ice Age periods into freezing ones. Straight-tusked elephants may have made temperatures rise during interglacials. Both types of elephant had all but vanished by 10,000 years ago, never to return. Since then, forest cover has increased sharply while the climate has been unusually mild and stable. Could the two be linked? Humans chopping down forests are now exerting at least as profound an effect on the world’s ecosystems as the mammoths had on theirs. By comparing the destruction wrought then and now, an alarming prospect emerges. Are we in the very process of making our own climate as volatile as that of the extinct elephants? Cores drilled from undisturbed glacial ice in Greenland and Antarctica have provided a wealth of information about almost constant shifts in the Earth’s climate over the past few hundred thousand years. Climatologists will tell you that we live in an interglacial period, in a world that is still going through an ice age that started 1.8Ma with the onset of the Quaternary period. (When I refer … Read More

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Fossil bones from the North Sea: An easy to way to collect fossil remains from the Ice Age?

Dick Mol (The Netherlands) Introduction In 1874, the first known mammoth remains were brought ashore, trawled off the coast of the province of Zeeland, The Netherlands. Fishermen, fishing for flatfish, caught these fossils as bycatch in their nets. (A bycatch is a fish or other marine species that is unintentionally caught while catching certain target species and target sizes of fish, crabs and so on) A museum associate in Middelburg described these bones in an extensive research report. This resulted in a sound basis for ongoing study of the lost life found on the bottom of the North Sea between the Netherlands and the British Isles, about two million to 10,000 years ago. For years the fishermen brought their bycatches ashore. Usually, these were large bones and teeth, both of mammoths and whales. In fact, the North Sea bottom used to be a vast plain during the Ice Age with mammoths walking around in large herds and this area must have been a paradise for large mammals. Apart from the mammoth remains, other species like wild horses, giant deer, deer, lions, bears, wolves, rhinos and others have also been found. Fig. 1. An upper molar of a woolly rhino, Coelodonta antiquitatis (BLUMENBACH). Thousands and thousands of woolly rhino remains have been fished from the southern bight of the North Sea between Britain and the Netherlands. Thousands and thousands of these remains ended up in Naturalis, the National Natural History Museum in Leiden. Today, this museum holds one of the largest … Read More

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Early Eocene London Clay deposits at High Ongar, Essex (Part 2)

Bob Williams (UK) In the previous part of this article (see Early Eocene London Clay deposits at High Ongar, Essex (Part 2)), I located the beds exposed at High Ongar in Essex (TQ 556809) within the general, stratigraphic framework of the London Clay. I also argued that examining the habitats in which families of crustacea live today provides clues about the sort of habitats that may have existed when the London Clay in the pits at Aveley in Essex and Ongar (TL 562024) was deposited. In this part, I will continue this comparison using modern lobsters, shrimps and other animals to provide clues about the habitats that may have existed at Ongar and at various other London Clay sites when their fossil relatives were alive. I will also show how one can locate a site like Ongar within the stratigraphic column. Fig. 1. Estimated position of the clay exposures at High Ongar Essex and nearby Aveley, showing the London Clay sedimentary deposits. At this point, it is worth bearing in mind the conditions in which the London Clay deposits are believed to have been laid down. London Clay is not one, uniform deposit. There are a number of sedimentary horizons within the deposit, each horizon reflecting the environment in which it was formed. Broadly, the London Clay is thought to have been laid down in a marine environment influenced by a tropical or subtropical climate. Water depth is thought to have averaged about 200m, but would obviously have varied locally. … Read More

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Book review: The New Forest – Geology and Fossils, by James Barnet

Those of you who have read a few of my book reviews will know that I love geo-guides to small geographical areas, rather than just the big geological scientific issues. In fact, there are lots of good UK guides like this one, to areas such as Dorset and Yorkshire, and many areas of Scotland and Wales, for example. And this is another excellent example of that genre.

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Early Eocene London Clay deposits at High Ongar, Essex (Part 1)

Bob Williams (UK) I first encountered the geological deposit known as the “London Clay” when I accompanied a friend to an exposure of the stuff. He told me that it was good for collecting fossils. It was and I was taken aback by the quality and quantity of fossil material. However, I knew nothing at all about the geological details of the sediment. However, like all keen amateurs, I wanted to know more about the deposit. To the uninitiated, the name “London Clay” suggests a single, uniform deposit. However, in truth, it does not fit that description. The name is given to a sedimentary deposit that contains at least five different and distinctive horizons (referred to as Divisions A to E). They were laid down in early Eocene times (50 to 54Ma) in conditions that were particular to slightly different environments or habitats (I use the terms interchangeably in this article). In a non-scientific way, the London Clay environments can be compared to the environments found in an ocean such as the Indian Ocean. Fig. 1. Estimated position of the clay exposures at High Ongar Essex and nearby Aveley, showing the London Clay sedimentary deposits. In broad terms, it is possible to describe the Indian Ocean as having warm, marine waters, being subject to tropical or sub-tropical climates and containing particular life forms. However, a variety of individual habitats can also be found in the Indian Ocean. There are shallow waters, deep waters, coastal waters, reef systems, trench systems, rocky … Read More

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Mammoths and the Mammoth Ivory Trade

Dick Mol and Bernard Buigues (The Netherlands) The ivory industry is flourishing using mammoth tusks and, illegally, the tusks of modern elephants. The growing hunt for mammoth tusks hampers palaeontological research and, as the two ivories are hard to distinguish, enforcement of endangered species legislation is impeded. Changes in legislation may not be practicable. However, education of the mammoth hunters may result in a win-win situation. This has now begun and the resulting co-operation has already lead to, and may lead to, more important discoveries and the securing of the remains for scientific exploration. Introduction The use of mammoth ivory for the construction of tools and artefacts is already known from Palaeolithic time. Our ancestors have used it for weapons and ornaments. The quality of the ivory of woolly mammoths, Mammuthus primigenius, found in the permafrost of Siberia as well as in North America (Alaska, USA and Yukon, Canada), is of outstanding quality and easily processed by the ivory industry. The quantity of traded ivory is substantial and the first overview of those traded amounts has been archived by Tolmachoff (1929). After this inventory, the trade has continued at an accelerated pace, especially during the last decade. Apart from the commercial value for the ivory industry, individual collectors and natural history museums often want to possess complete tusks. These intense collecting activities destroy enormous amounts of palaeontological data and obstruct the investigation of Pleistocene mammals and their habitats. It was our objective to start a discussion on how to counteract … Read More

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In search of dinosaur eggs in Mongolia

Steven Ballantyne (UK) The Scientific Exploration Society is a well-established, UK-based charity that undertakes scientific research and community aid work in remote parts of the world. As an expedition leader for the Society, it proved to be an exciting challenge for me to lead a  month-long expedition in 2006 across the infamous Gobi Desert in Mongolia in search of dinosaur fossils. Professor Altangerel Perle, the renowned palaeontologist from The National University of Ulaanbataar, headed the scientific team. (Professor Perle has no less than six dinosaurs named after him.) The team totalled 20 in number and included Mongolian palaeontology students, botanists and zoologists, and also team members from the UK, Australia, Tasmania and Greece, all with a deep-seated interest in science. Fig. 5. The redoubtable Professor Perle. As an introduction to then non-palaeontologist members of the team, we spent our first day surveying and working at the Flaming Cliffs. This is an historic site, made famous in the 1920s by the great explorer and palaeontologist, Roy Chapman Andrews. Here, we found tiny fossil fragments of the dinosaur Protoceratops andrewsi. This was achieved by gently and methodically brushing the surface sand – a job we would become expert at over the forthcoming weeks. Jinst was the location of the first of our two significant finds. This was a very well-preserved turtle shell, a stark reminder to all that this seasonally hot and dusty land was once an ocean. The fossil included the complete upper and lower body shell and, excitingly, the small … Read More

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england geology historical / biographies minerals mining urban, art, anthropology

Fabulous Fluorite: Derbyshire Blue John

Richard M Haw (UK) Blue John is a unique variety of blue-purple banded fluorite. Hydrocarbons or oils have been deposited on some of the crystal surfaces while the mineral was forming. These oil layers are partly responsible for giving the stone an alternate blue and white banding, best seen when the stone is cut in section. It is not known to occur anywhere else in the world and is confined to an area of about 1km³ of the Carboniferous “reef” limestones at Castleton in Derbyshire. Fig. 1. Old picture taken sometime in the 1870s, showing miners digging in the Old Dining Room, now part of the show caves. I have been involved with the public caverns here for a while and I am sure many of you have visited them. However, there are many people who have never even heard of Blue John, so the following article gives a general overview without intending to be too technical. The area Castleton is a small village located in Derbyshire’s “Peak District” between the cities of Manchester and Sheffield. The village is dominated by the ruins of Peveril Castle that was built by the Normans to oversee lead mining in the area. The scenery around Castleton forms a dramatic backdrop and the rolling limestone hills end abruptly atthe vertical face of Mam Tor. Beyond and to the north are the gritstone moors known as the “Dark Peak” that eventually lead up to the two-thousand-foot-high plateau of Kinder Scout. Castleton and the surrounding area … Read More

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Seeing dramatic folded strata from the car: Sideling Hill, Maryland, USA

Deborah Painter (USA) In many states of the United States and in many locales in the United Kingdom, there are historic markers at the site of an important historic home or event. However, I wonder if every accessible rock formation had its own historic marker, would more people take the time to learn about it? The entire history of the planet is seen in rock formations. Just west of the town of Hancock, in the state of Maryland, USA at Mile Marker 74 on Interstate 68 (coordinates 39° 43’ 11.54” N, 78° 16’ 58.29” W) is the Sideling Hill road cut, a textbook example of tight folds in a mountain (Fig. 1). Until relatively recently, the visitors centre located adjacent to the cut was a perfectly complete historic marker. It gave travellers not only a place to stop to buy refreshments and relax at a picnic table surrounded by shade trees. It also provided an opportunity to read about the history of a spectacular cut in a mountain resulting from a need for safer transportation through a difficult and rugged stretch of road. Fig. 1. View west along Interstate 68 and US Route 40 (National Freeway) from the Victor Cushwa Memorial Bridge as it passes through the Sideling Hill Road Cut in Forest Park, Washington County, Maryland. (Credits: Famartin, Wikimedia Commons.) The centre still helps motorists see a geological formation safely from a walkway and an enclosed bridge. Sideling Hill’s transportation story goes back to the earlier days of road … Read More

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Urban geology: The battery on the Sloterweg

Stephen K Donovan (The Netherlands) The city of Amsterdam in the Netherlands is surrounded by a great defensive earthwork on its landward side, the Stelling van Amsterdam (= Defence Line of Amsterdam), along which are a series of forts and batteries (Figs. 1A-E and 2). This major structure was built between 1880 and 1914. The principle feature of this defensive system is a raised earthen embankment or dyke, still imposing today although breached or flattened in many places to make way for modern developments, most commonly roads. The embankment is often flanked by two canals, one on either side. Fig. 1. (A, B) The Battery on the Sloterweg, Hoofddorp, Noord Holland, the Netherlands.(A) General view of the Battery, looking approximately northwest.(B) Nameplate.(C-E) Three views of the restored embankment between the Battery on the Sloterweg and Hoofddorp station.(C) The view southeast on the northeast side of the embankment from the R-Net bus stop (routes 300 and 310) at Hoofddorp station, looking towards the Battery. The cycle path crosses the bridge and continues away from the photographer. Note the blue tractor scraping the embankment.(D) The view southeast on the southwest side of the embankment from the R-Net bus stop at Hoofddorp station, looking towards the Battery (at the end of the path in the distance). Again, note the tractor scraping the surface.(E) The view northwest from the Battery, looking towards Hoofddorp station, showing the ‘exposure’ in the foreground, which was particularly productive of builders’ rubble, including lithic fragments.(F) Details of the granite … Read More

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Geology museums of Britain: The National Stone Centre, Derbyshire

Jon Trevelyan Britain has a long and proud history of geological museums (and museums that have significant geological collections) dating back at least to early Victorian times. One need only think of William Smith’s revolutionary and magnificent, 1829 Rotunda in Scarborough to understand this (Fig. 1). Fig. 1. The Rotunda, Scarborough. Here, Smith’s fossils were (and are once again, after significant renovation to the building) arranged up a spiral staircase in the order they occur in the rock column – an extremely modern way of doing things. And, of course there is Richard Owen’s Victorian masterpiece, the Natural History Museum in London with, among many other things, its dinosaurs and exhibits of other fossils (Fig. 2). Fig. 2. The Natural History Museum, London. However, the venerable NHM raises an important question. To create a display for the public, to what extent should museums use push-button technology and pretty pictures, rather than displays of the actual subject matter? In recent years, it seems that museums increasingly want to cater merely for children (and certainly not adults), who (apparently) can only be engaged by technology rather than, for example, a well-labelled and beautifully prepared fossil ammonite. The belief seems to be that they simply cannot look at exhibits in the way that Victorians did – with specimens set out in cabinets – but rather, need to be engaged by electronics and graphics that are one remove from the subject matter itself. I suspect that it was this belief that lead the NHM … Read More

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BOOK REVIEWS england fossils geology northern ireland palaeontology scotland united kingdom urban, art, anthropology wales

Book review: Trilobites, Dinosaurs and Mammoths: An introduction to the prehistory of the British Isles, by James McKay (for the Palaeontological Association)

This is an interesting little booklet and very much a new departure for the Palaeontological Association. You will be aware that I have reviewed several of its many excellent fossil guides in this magazine. However, this recently published tome is somewhat different.

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Urban geology: An inselberg in Rotterdam

Stephen K Donovan (The Netherlands) The Low Netherlands, much of which is below sea level, is a broad area of the country that (very approximately) parallels the coast and is kept ‘dry’ by major works of civil engineering (IDG, 1985, pp. 6-7). Geologically, it is a flat expanse of Holocene deposits; most of the author’s experience is in the coastal plain (de Gans, 2007), where I both live and work. There is no significantly older geological deposit or feature anywhere in this region – no coastal cliffs, mountains or quarries to tempt the attention of the wandering Earth scientist. So, it is commonly the ex situ that demands the geologist’s attention rather than the in situ. For example, I have commented previously on such diverse topics as the use of imported limestone to make a false natural bridge (Donovan, 2014), various aspects of building stones (for example, Donovan, 2015, 2019) and gabions mimicking sedimentary bedding, at least from a distance (Donovan, 2018). Of these examples, the natural bridge is the most exotic; although such a bridge might be expected in karstified limestone landscapes almost anywhere, my own experiences of them are limited to the Antilles (Miller and Donovan, 1999; Donovan et al., 2014). In this article, I describe a further man-made structure mimicking an even more exotic geomorphological phenomenon, most closely associated in the minds of Earth scientists with Africa. It is a structure that I have, until now, only known from textbooks – I refer to a mock inselberg … Read More

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Barton Beds of Hampshire

Ray Chapman (UK) The cliff exposure of the Barton Beds between Highcliffe in Dorset and Barton on Sea in Hampshire are the type section of the Bartonian age and are highly fossiliferous. They are Middle Eocene in age and were deposited between 41.3 and 37Ma. They extend to Southampton in the east, Wareham in the west and Fordingbridge in the north with some other minor exposures in Southeast England. Fig. 1. The Barton Beds viewed from Highcliffe. The beds are marine clays, silts and sands deposited in a generally shallow sea that stretched to the southeast of the present shoreline and across the Hampshire-Dieppe Basin. Terrestrial input was from the west and northwest. The environment was sub-tropical partly because the average global climate was higher than today and partly because Britain was about 100 further south of its current position. The beds are alleged to contain some 600 species of molluscs, marine vertebrates, reptiles and other taxa. Christchurch Bay, between Milford on Sea and Bournemouth, has developed over the last 10,000 years. Previously, the ‘proto-River Solent’ ran eastwards from the rivers Frome, Piddle, Stour, Avon and other small rivers. It ran behind what is now the Isle of Wight along what is now the Solent and joined the large ‘Channel River’ flowing westwards from the Rhine, Rhone and Seine. At the end of the last glacial period, the chalk ridge to the south, which joined what is now the Needles on the Isle of Wight and Handfast Point on Studland, … Read More

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BOOK REVIEWS dinosaurs geology historical / biographies palaeontology

Book review: Rebels, Scholars, Explorers – Women in Vertebrate Paleontology, by Annalisa Berta and Susan Turner

This is certainly a somewhat different sort of book from those I usually review. As it makes clear, women have always played key roles in the field of vertebrate palaeontology, going back centuries. However, other than perhaps the most best known historical female vertebrate palaeontologists comparatively little is known about these women scientists and their true contributions have probably been obscured. In this context, the book aims to reveal this hidden history, thereby celebrating the diversity and importance of women VPs.

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Urban geology: Brush up your neoichnology

Stephen K Donovan (The Netherlands) It was a dry Saturday in February (2014), but it was blowing a gale such that some gusts stopped me dead in my tracks. My son, Pelham, and I were out for a walk in the Haarlemmermeersebos, which roughly translates as ‘the wood of the lake of Haarlem’. The area where we live, which includes the nearby Amsterdam Schiphol International Airport, is the bed of a lake that was drained over 160 years ago. So it is a flat, featureless, polder landscape (Ministry of Foreign Affairs, 1985, pp. 10-11), apart from what man has put into it; and is criss-crossed by canals and, less commonly, dotted by lakes. The canals in the Haarlemmermeersebos landscape that are intended for water transport are few; rather, most are part of the water management system in a landscape that is below sea level. In such a landscape, the weekend geologist must look hard for ‘exposures’. Building and decorative stones are always of interest (Donovan, 2014). Beachcombing on the nearby North Sea coast can be rewarding, particularly after storms when Quaternary peat clasts are washed up on the shore (Donovan, 2013). But, in truth, there is more potential for the geomorphologist than the geologist or palaeontologist. The point of our excursion in a gale was to model palaeontological collecting and to hone our observational skills in the open air. I had discovered a path paved with many hundreds of recent sea shells and rare flint pebbles in the Haarlemmermeersebos (Fig. … Read More

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england geology historical / biographies palaeontology

Mary Anning and the Jurassic Dragons

Ray Goodwin (UK) It was a hot and sultry summer afternoon in August 1800. A happy crowd was gathered in the small town of Lyme to watch an exhibition of horse jumping in the nearby Rack Field. No one could have guessed that, before the day was out, tragedy would strike from the skies and three women would lie dead beneath a clump of elm trees. With a little 15-month-old baby in her arms, Elizabeth Haskings and two young friends hurried for shelter as, late in the afternoon, the sky darkened and torrential rain began to pour down from the heavens. Minutes later, a brilliant flash of lightning hit the trees and a terrible thunderclap reverberated around the nearby cliffs. As the rain stopped, a horrified crowd walked towards the trees and, amid the charred remains, they saw the outlines of three huddled bodies lying on the ground. The three women were terribly burnt and had been killed instantly. Sheltered by the body of Elizabeth, the baby lay unconscious but, after bathing in water, soon recovered consciousness. Legend has it that she was transformed from being a quiet, ordinary baby into a child of exceptional liveliness and intelligence. Whether this was strictly true or not, we may never know.  However, it is a fact that the child, whose name was Mary Anning, was destined to become one of the greatest palaeontologists of the early nineteenth century. Mary Anning was born on 21 May 1799 in the small Dorset town of Lyme. … Read More

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Seeds from the London Clay

Joe Shimmon (UK) With good luck and perseverance, some beautiful fossils can be collected from the London Clay, which outcrops in the south east of England. The phosphatic remains of crustacea, fish and other, rarer vertebrates are well known, and information and images of them are easily accessed, particularly on the Internet site: Sheppey Fossils. (See also Fred Clouter’s article, Sheppeyfossils.com: The genesis of a website, for a review of this website.) However, the formation’s hugely diverse floral assemblage is often overlooked, with little easily accessible information to be found on the web. Therefore, in this short article, I aim to introduce the most interesting of the London Clay’s plant fossils – its fossil seeds. Fig. 1. Various seed shapes. The London Clay Formation is a marine geological formation of Ypresian (Lower Eocene Epoch, about 56 to 49Ma) age. It consists of stiff, bluish-coloured clay, which becomes brown when weathered. And it provides one of the most varied fruit and seed floras in the world, which also happens to be the only diverse flora fossil assemblage from the Lower Eocene in Europe. There are 500 or so recognised species, which would have inhabited mangrove and tropical habitats much like Indonesia or East Africa today – bordering a warm, shallow ocean. Commonly found are specimens belonging to magnolia, vines, dogwoods, palms, laurel and bay, with a third of the fossil species present belonging to genera that are still found living today. Fig. 2. A selection of seeds. London Clay seed fossils … Read More

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Alluvial gold: A geological model (Part 2)

Philip Dunkerly (UK) In A geological model for the alluvial gold environment (Part 1), the first part of this article, I discussed how alluvial gold is found and suggested a geological model for alluvial gold deposits. (Readers are recommended to have another look at that part to remind them of the model.) In this second part, I now turn to the nature of the gold itself. Fig. 1. Gold bullion bars of 400 troy oz. Fig. 2. Sites from around the world. Gulch gold Gulch gold is the coarsest that exists in any part of a river system. If nuggets (pieces of gold weighing more than 0.1g) are present, they will mostly be found in gulches (narrow ravines), provided suitable traps are present, such as irregular bedrock. In gulch alluvium, the vast majority of the gold will be found on, or in crevices within, the bedrock. Gulch gold is often coarse and angular and may contain silicate debris, especially quartz. As examples, gold from Victoria Gulch on the Klondike was described as “sharply angular”. In the Ballarat gullies, some enormous nuggets were found and Canadian Gully yielded nuggets of 50.4, 34.7 and 31.4kg. At Bendigo, White Horse Gully, a 17.8kg nugget (including some quartz) was found. (Interestingly, of a list of 92 Victorian nuggets, 34 came from localities specifically named “gullies”.) Finally, in the Sierra Nevada of California, most of the gold is from gulches or minor streams close to croppings. Fig. 3. Old hydraulicking operation of terrace gravels, note … Read More

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