Dr Trevor Watts (UK) In the first part of this article, I discussed the Middle Jurassic environment in the region of Whitby, on the northeast coast of England at the time when dinosaurs roamed there. In Part 2 (see The dinosaur footprints of Whitby: Part 2 – problems matching footprints to dinosaurs), I looked at how the footprints were formed and preserved, and at the problems in identifying and classifying them. And in Part 3 (see The dinosaur footprints of Whitby: Part 3 – a brief look at the six footprint groupings), I discussed the six major forms of footprints to be found in the area. In this fourth and final part, I will describe each of the four locations close to Whitby, and hope to give an idea of what footprints are there to be searched for. Fig. 1. Reproduced from the first part of this article – the four sites around Whitby where dinosaur footprints are commonly found. 1. East Cliff Beach Fig. 2. East Cliff Beach, with four minor headlands and five bights. Even on a much-visited beach such as East Cliff in Whitby, dinosaur footprints can be found without a lot of difficulty. This is a variable beach with ever-changing areas of rock platform, masses of sand and boulder fields, punctuated by frequent cliff falls and slumps. Every summer weekend, it is home to hundreds of curious fossil-searching families. It is very easily accessible down a slippery concrete ramp during the lower half of the tide … Read More
Dr Trevor Watts (UK) In my previous articles in the series, I looked at the environments that allowed dinosaurs to flourish in the Whitby area during the Middle Jurassic and to leave their footprints. Then I considered the factors and problems in trying to match the footprints to particular species of dinosaurs. In this part, I will look at the six different forms that dinosaur footprints mostly take in the region. 1. Theropods Fig. 1. A Squabble of Theropods. The toes of theropods tend to be quite slender, they are longer than the heel and the foot is longer than it is wide. Theropods, meaning “beast-footed”, include well-known dinosaurs such as Megalosaurus, Velociraptor, Tyrannosaurus, Allosaurus, Tarbosaurus, Troodont, Deinonychus, Coelophysis and a great host of turkey-sized raptors. Most of these species were not around at this specific time and place (although Megalosaurus may well have been). However, they were principally fast-moving carnivores that hunted or scavenged. They all had sharp, serrated, meat-ripping teeth; and were mainly bipedal – that is, they ran on two strong rear legs, with much shorter and weaker forelimbs. Figs. 2, 3, 4 and 5. Examples of small and large theropods, and their feet. Their footprints are said to be “tridactyl” – a word somewhat pretentiously created in the early nineteenth century from the ancient Greek for three fingers. It loaned scientific credence and academic gravitas to this new field of study. Most of the early footprints found in the UK and along the Connecticut Valley in … Read More
Dr Trevor Watts (UK) In the first part of this article (The dinosaur footprints of Whitby: Part 1), I considered the immediate surroundings of Whitby as a seemingly unlikely place to find many dinosaur footprints; and I looked at the environments that existed here in mid-Jurassic times; and finally discussed how the footprints came to be shaped as I find them. In this part, I look at the problems that are encountered in trying to match the footprints to particular dinosaur species, and at the idea of ‘ichno-species’. I also suggest a simple compromise in classifying the footprints. Matching a footprint to a particular species of dinosaur isn’t easy, for several reasons. 1. Relatively few dinosaur species have been identified as living at this time or in this region In many parts of the world, the relevant rocks have been eroded away, or are deeply buried under later beds, or no beds were laid down, or the environment was marine. On a worldwide scale, there are remarkably few places where footprints coincide with skeletal remains that might be matched with them. The Middle Jurassic is a time about which very little is known with regard to the variety, numbers and development of dinosaurs, anywhere in the world. In fact, it is the least understood part of the Jurassic. Fig. 1. Replica foot and footprint photographed at both Dinosaur Valley State Park, Texas and Springfield Science Museum, Connecticut. In this particular area, it is extremely rare to find any skeletal remains … Read More
Dr Trevor Watts (UK) Introduction I recall reading a sentence in a book some time ago that went something like, ‘Occasionally a dinosaur footprint may be found along the coast.’ In fact, dinosaur footprints are superabundant along the Yorkshire Coast. On a day’s visit to any of 15 or 20 beaches, we (my wife, Chris, and I) would consider finding less than a dozen footprints to be a little disappointing, unless they were especially clear, part of a track or an unusual type. More commonly, we would expect to find two dozen or so recognisable prints. Fig. 1. Map of the UK showing the position of Whitby on the coast of Yorkshire. The outline map of the UK is reproduced by courtesy of d-maps at http://d-maps.com/carte.php?num_car=2557&lang=en. This article is intended to give an impression of how common they are, what to look for, what might have made them and where exactly they can easily be found. It is not meant to be a technical, profoundly scientific paper: it’s a discussion. I hope it will provide an idea of what they might look like when you’re out on a beach (that is, the sort of things to be looking for on the rock surfaces, so you can recognise a footprint – they aren’t always clear at first sight). It is largely a case of seeing the ridges and bumps – the curves and angles, and the grooves and depressions on a rock surface – for what they are. This is a … Read More
The Jurassic Coast Trust is certainly producing some good books these days. I have alraedy reviewed one (The Jurassic Coast: An Aerial Journey through time by Peter Sills) and I think these two might even be better. As is well known, in recognition of its wonderful geology, the coast between Orcombe Rocks in southeast Devon and Old Harry Rocks in south Dorset was granted World Heritage status in December 2001.
Khursheed Dinshaw (India) In the first part of this article (see Siwalik Fossil Park, Himachal Pradesh State, India: Part 2), I introduced Siwalik Fossil Park, its geology and some of the animals and plants whose fossilised remains have been found there. In this second and last part, I cover some more of the mega fauna that once lived here. In fact, the Siwalik Fossil Park, in the state of Himachal Pradesh, India is a significant step towards the preservation of prehistoric animal sites, conserving and repairing the current natural environment and utilising them for scientific and educational purposes. In fact, the park is a rich geological heritage. The environment and climate was highly favourable for the development of elephants in the Siwalik region between 20 and 1.5mya (Figs. 1 and 2). Approximately 22 fossil species have been found, but all became extinct one million years ago with the beginning of the Ice Age. Fig. 1. The section displaying elephant fossils. Fig. 2. The proximal end of an elephant’s femur, which became extinct 1myrs ago at the beginning of the ice age. Nowadays, only one species is found in India (the Indian elephant, Elephas maximus indicus). The fossil skulls, jaws, teeth and bones of extinct species are displayed at the museum along with a life-size fibre glass model of the extinct giant species, Stegodon ganesa (Figs. 3 and 4). Fig. 3. The cranium of Stegodon insignis, which existed during the Plio-Pleistocene period. Of the species that existed during the Plio-Pleistocene period, … Read More
Deborah Painter (USA) Cornwallis’ Cave, a feature along the bluffs overlooking the York River in historic Yorktown, Virginia in the USA, is not a real cave and may not even have sheltered British General Charles Cornwallis during the final weeks of the American War of Independence. The National Park Service, which oversees the feature, has little historical evidence that Cornwallis ever used it as a meeting place or as shelter. He probably used a bunker located elsewhere along the river. It is one of the United States’ best-known man-made ‘caves’ and, though composed of Pliocene epoch coquina – a type of sandstone composed mainly of fossil shells – it is unrelated to actual karst features in the area. This feature is a cultural resource that contains holes carved in the stone cave walls for wooden beams to enable storage of supplies during the later American Civil War and is part of the Colonial National Historical Park encompassing many hectares. The cultural history Cornwallis’ Cave is approximately 12.19m in length. It has been sealed off partially by the National Park Service and one can only enter approximately a meter into the cave and view its interior through a wrought iron gate. Were it not for the historic value of the feature and its proximity to the site of testing of mid-nineteenth century hot air balloon warfare, the ‘cave’ might have been levelled long ago. Thankfully, it has not. It is rich in fictional lore, including its reputation for ghosts. A regular … Read More
Jack Wilkin (UK) Palaeoclimatology is the study of past climates and environments using climate proxies, that is, the preserved physical characteristics of past, rather than using direct measurements of variables, such as temperature, levels of CO2 and so on. Many different types of proxies are used including, but not limited to, ice cores (Petit et al., 1999), lake and ocean sediments (Cehn et al., 1999), and fossil data. Many fossil groups have specific environmental and ecological tolerances and so can be used to determine palaeotemperatures and palaeoclimates (Jones, 2006). It is the data collected using dendroclimatology and other plant macrofossils that will be examined in this article. Dendroclimatology Dendroclimatology is the use of tree rings to determine long-term climatic trends. This is in contrast to dendrochronology, which is dating using tree ring data. Dendroclimatology is used extensity to study the climate during the Holocene (Fig. 1) but has also been applied to the Late Cretaceous of Alaska and even the Permian of Antarctica (Taylor et al., 2009). The thickness of the tree rings helps scientists work out how much the trees had grown within a given year. Then, by comparing the rate of growth to members of the same, or closely related, genera or species, they can determine the palaeoenvironment. Fig. 1. Variations in tree ring width translated into summer temperature anomalies for the last 7,000 years, based on samples from Siberia. Source: Institute of Plant and Animal Ecology https://upload.wikimedia.org/wikipedia/commons/5/53/Yamal50.gif. Dendroclimatology can also be used to gather isotopic data. As … Read More
This is an odd little book. Produced by the Craven & Pendle Geological Society and edited by Paul Kabrna, it sets out to cover the geology of Craven Lowlands through a series of chapters written by different contributors.
Diana Clements (UK) The Geologists’ Association (GA) was formed in 1858 and, from its inception, was an inclusive organisation set up to embrace both professional and amateur geologists, unlike the Geological Society, some 50 years older, which was only intended for professionals. Women were accepted from the beginning – similar organisations of the time were habitually men only. It was intended as a meeting-place for like-minded people and fieldtrips were always an important part of the Associations’ activities. As early as 1895, Local Groups around the country were set up to extend activities nationwide; now we have 17 Local Groups with a further 72 other geologically-related societies that are affiliated with the GA. The aims that we adhere to now were developed gradually and foremost among them is to make geology available to a wider public. The Proceedings of the Geologists’ Association first appeared in 1859, only a year after its formation, and included written papers presented first to members at the Friday lectures and the write-ups from the early fieldtrips. These are often important historical documents of geology in a bygone age, no longer visible, particularly in urban environments. Fig. 1(a) A fieldtrip to Gilbert’s Pit, Charlton in 1913, when the quarry was operating. Fig. 1(b) The same face in 2016, with steps erected to view the remaining exposure of geological interest. As well as the images in the write-ups, the GA possesses a large archive of photographs and associated ephemera documenting the activities of the Association since the … Read More
If you can see past the somewhat robust title (a reference to James Hutton’s discomfort riding around Scotland on horseback during his geological investigations), this is an interesting read, combining both geological science and humour in just about the right measures.
A History of Plants in 50 Fossils would seem to be the follow up to the well-received A History of Life in 100 Fossils. However, this time, this glossy hardback tells the story of plants on earth using significant fossils that are, for the most part, kept at the Natural History Museum in London.
The Geologists’ Association has produced yet another great guide, this time on the geology of Wales. However, this is a slightly different beast from most of their other publications.
Steven Wade Veatch (USA) The huge petrified redwood stumps near Florissant stretch the limits of my understanding. I’m left with only wonder, like a poem I can’t explain. Under the dominion of a clear blue sky, the afternoon light ricochets off the stone, displaying the myriad beige and brown hues of the fossil stumps. Their stony surfaces contrast with tufts of grass that surround them. The nearby orange-red bark of ponderosa pine and the scent of the forest adds another layer of magic, while silent mats of pine green moss cluster in the shadows. Pale lichens cover some of the stone tree rings. The warm summer air buzzes with insects. Fig. 1. View of the Florissant Fossil Beds National Monument’s iconic “Big Stump”. (Photo by S W Veatch.) For me, the stone trees are a portal where the past joins with the present, and time seems to have stopped. I imagine how it all began 34 million years ago when a cluster of nearby volcanoes, once dormant, erupted. It started with a blast of ash and fiery molten rock shooting out from awakened vents. The air became heavy and dark, as plumes of grey ash hazed eastward towards what would become Florissant. Rainfall mixed with loose sediments on volcanic slopes, forming mud – the colour of morning coffee – that rushed down the slopes of the volcanoes at speeds of up to 145km an hour. Ash rained out of the sky and mixed with the spreading mud. The mud popped … Read More
Frank Wesselingh (The Netherlands) In the southern Delta area of the Netherlands, several beaches exist where the collector can collect a wide variety of Tertiary and Quaternary fossils. One of the well-known beaches is that of Cadzand that has been particularly rich in fossil shark teeth (but also fossil shells). The richest of the Dutch localities, a beach called De Kaloot, was under threat because of a proposed container terminal that would obliterate most, if not all, of the beach. Fig. 2. A view down the bank at De Kaloot. Fig. 3. A walk along the beach at De Kaloot. De Kaloot is located on the North bank of the Westerschelde estuary. Tidal currents are very powerful, eroding the seabed in front of the beach down to 60m in depth. As a result, ﬁve different fossiliferous formations in the subsurface are revealed. The fossils from these deposits ﬁnd their way to the beach, especially after heavy SW storms. The fossil ﬁnds are diverse but comprise mainly fossil shells of Pliocene and Quaternary age. We estimate that over 500 species have been collected from De Kaloot. In addition, from these shells, shark teeth, vertebrate remains, bryozoans and other fossil groups have been collected. On some days, about 75% of the shell banks consist of fossil shells. This locality is unrivalled in its species richness, and it is said that it is under threat. In 1999, the Province of Zeeland, where De Kaloot is located, announced plans to build a container terminal. The … Read More
Jens Lehmann (Germany) Plagiostoma – a record of about 200 million years Are there any boring fossils out there in the ground? I do not think so and to demonstrate this, an “ordinary” fossil find is focussed on here. We are talking about “just” a mussel, but one that belongs to an extinct group and even this alone makes it exciting. Plagiostoma is a member of the file clam family. This genus is only known from the fossil record and appeared probably in the Permian and certainly by the Mid-Triassic period, about 240 million years ago. This genus became extinct at the Cretaceous-Palaeogene boundary – according to the most recent timescale dated 66 million years ago. At least two dozen of species have been described so far. The shells of Plagiostoma are moderately inflated and can reach the size of a hand, with an oblique oval outline. It is a common fossil, for example, in the Muschelkalk (Middle Triassic) in the Germanic Basin and quite a few continental countries. It is also well known from the Blue Lias of Southern England and stratigraphic equivalents, and can be frequently found at Monmouth Beach in Lyme Regis, a world-famous spot for fossil hunting. The giant Plagiostoma The species frequently encountered at Lyme Regis is Plagiostoma gigantea and the name already suggests that it is a giant amongst the representatives of the genus. The specimens figured here (Fig. 1) are of moderate size, with a total length of each about 8cm, but there … Read More
Jon Trevelyan (UK) This is the much anticipated 4th edition of the GA’s Yorkshire Coast guide and it was well worth the wait. From personal experience, I was aware that the previous editions were extremely good for any geologist – professional, academic or amateur – who is attracted by the wonderful scenery and fascinating geology of this part of the UK coastline. However, this new edition is altogether an even better product. The full colour photographs, diagrams and maps make for an entertaining and informative read, and a new chapter using seismic profiles provides additional information not in previous editions. Like all GA guides, this introduces the geology of the Yorkshire Coast in an accessible and readable style, including coverage of its structure, stratigraphy, palaeogeography and environments, and its industrial history. It then provides 17 excursions covering areas from Staithes in the north to South Holderness in the south. This takes in all the obvious areas that any fossil collector in the area will know – like Staithes to Port Mulgrave, Saltwick Bay to Whitby, Speeton and Flamborough Head – but also includes some new locations, such as Betton Farm Quarries, which is a SSSI. I was lucky enough to visit this fascinating site with the authors, who showed us why this excellently exposed localised, coral reef from the Upper Jurassic was worth including in the guide. (There is also an excellent charity-run tearoom and restaurant to visit after looking at the rocks.) Pete Rawson spent his academic career in … Read More
Violeta de Anca Prado and Stephen McLoughlin (Sweden) When people think of fossils, they usually picture slabs of rock bristling with bones, or the shells of ammonites or trilobites. Most do not even consider that delicate organisms, such as fungi or bacteria, can even fossilize – they seem too fragile to be preserved as they lack a hard skeleton. In many cases this is true. Microscopic organisms that lack hard parts have fewer chances of being fossilised but, despite the odds, delicate fungi have a fossil record that is more extensive than generally thought. The fossil record of fungi goes all the way back to the Proterozoic. Identifying the oldest fossil fungus is difficult because many reports of early fungi have later been reinterpreted as filaments of green algae or cyanobacteria. Nevertheless, increasing reports of fungi from the late Proterozoic are consistent with DNA comparisons (the so-called “molecular clock” method) that suggests fungi, plants and animals diverged about 1,600 million years ago. What is more certain, is that fungi were actively diversifying in terrestrial habitats as soon as plants gained a foothold on land. Fungi are fossilised in diverse styles. Usually, the best examples are preserved inside permineralized (petrified) wood or peats. The process of permineralization involves the organic tissues becoming entombed within mineral matter (usually calcium carbonate or silica), which is precipitated from solution in groundwaters. More rarely, we encounter fungi preserved as impressions, which are like a “fingerprint” of the organism – the original fungus has decayed but … Read More
The long awaited PalAss guide to Wealden fossil flora and fauna has finally arrived and what a magnificent tome it is. At 769 pages and 35 chapters, it is by far the most ambitious and complete of their guides, covering various vertebrate groups, together with invertebrates, plants and stratigraphical descriptions of what can be found on the coast and in the quarries of southern England and the Isle of Wight.
Deborah Painter (USA) Seated on the jet heading south to Florida, I thought of my upcoming field work in the central portion of the state. I also hoped to see some monkeys during my brief stay. I knew they were ‘invasives’ but I still wanted to see them. I had read that, many decades ago, rhesus monkeys were brought in for atmosphere in the Silver Springs area by an entrepreneur named “Colonel” Tooey, who was running a glass bottom tour boat operation named “The Jungle Cruise”. By now, the animals have established a breeding population. I also knew that the Withlacoochee, a river yielding vertebrate fossils from several Cenozoic epochs, was not far from where I would be. Therefore, I had my collecting permit from the state of Florida just in case I had a few hours to spare to look around the riverbanks. Upon arrival at the Orlando International Airport, I became instantly aware that most of the travelling public was going to, or coming back from, Walt Disney World and the Epcot Center. I was headed to a mostly wooded area in western Sumter County to do an ecological survey and wetland delineation on Federal lands, and was glad to leave the crazed traffic of the airport behind me, as my rental car sped toward the setting sun of a late September day in 2019. It did not take long for me to enter the agricultural lands where Brussels sprouts, cassava, pears and ornamental house plants were cultivated, … Read More
Stephen K Donovan (The Netherlands). Although it has a rock record that only extends back to the Early Cretaceous, the geology of Jamaica is sufficiently diverse to satisfy most appetites (Donovan & Jackson, 2012a, b). It lies within the North Caribbean Plate Boundary Zone and displays a range of geological structures, commonly faults, both ancient and modern. There are about 25 Cretaceous inliers, from small to large, each including a sequence of volcanic and/or sedimentary rocks that are rarely metamorphosed. The half-graben Wagwater Belt in the east, flanking the western margin of the Blue Mountain inlier, is a Paleogene succession of terrestrial red beds, shallow to deep water siliciclastics and volcanics. These older rocks are draped by thick sequences of Eocene and younger rocks, which are mainly sedimentary (Robinson, 1994). Of the sedimentary rocks, limestones from the Cretaceous to the Quaternary are particularly widespread (Fig. 1), covering about two-thirds of the island’s surface. Although only subaerially exposed for about the last ten million years, these limestones have been strongly karstified under conditions of tropical high temperatures and seasonal extreme precipitation (Donovan, 2002). This has produced widespread, and magnificent, karst topography. Fig. 1. Simplified geological map of Jamaica, showing the principal stratigraphical units (after Donovan, 1993, fig. 1). Key: B=Blue Mountain inlier; C=Central inlier. Stratigraphy of principal Cenozoic units: granodiorite=Upper Cretaceous to Paleocene; Wagwater Formation, Newcastle Volcanics=Paleocene; Richmond Formation=Paleocene to Lower Eocene; Yellow Limestone Group=Lower to Middle Eocene; White Limestone Group=Middle Eocene to Upper Miocene; Coastal Group=Upper Miocene to Quaternary; alluvium=Quaternary. … Read More
Rory Mortimore (UK) Flint in the Late Cretaceous Chalk: links across the European platform In a recent issue of this journal Paul Taylor wrote “We are very fortunate in Britain to host one of the most remarkable deposits in the entire geological record, the Chalk” (Deposits Issue 55, 2018, p.35, see Bryozoans in the English Chalk). Perhaps equally remarkable are the bands of flint associated with the pure white chalks (Figs. 1 to 3). Flints have attracted human attention since pre-historic times with some flint bands providing the preferred source rock for manufacturing stone-age tools (for example, the Late Turonian Floorstone Flint at Grimes Graves near Brandon in Norfolk, England (Figs. 4 to 6a and b; Mortimore and Wood, 1986), or the geologically much younger Early Campanian flints in the Harrow Hill Flint Mines in Sussex, England Fig. 7). Subsequently, Brandon flints were used as the vital spark for guns (that is, gun-flints, Skertchley, 1879; Shepherd, 1972) and these have been found as far afield as eastern North America (used in weapons of the American revolution) to the Fijian Islands in the Pacific (from Royal Navy guns). In the modern era flint remains a material of concern in engineering causing damage to core-drilling operations, tunnelling machines (Fig. 8) and cable trenching machines onshore and offshore northwest Europe. Flint also impacts the ease with which piles can be driven into chalk. To fully appreciate flint as a material and to assess the impact of flints on engineering operations has required establishing … Read More
Steven Wade Veatch (USA) Curious pupal cases made by prehistoric weevils, together with worm burrows, are found as trace fossils in rock exposures of the Upper Bridgewater Formation along the western coastline of the Eyre Peninsula in South Australia (Flint, 1992; Flint and Rankin, 1991; Rankin and Flint, 1992). According to Parker and Flint (2005), the Upper Bridgewater Formation is a middle to late Pleistocene aeolian calcarenite (a wind-blown, consolidated gritty calcareous sandstone). These trace fossils are found inland from the coast for a distance of about 40km. Microscopic analysis of these ancient pupal cases shows they are made of gritty sand and gravel that were cemented by calcite over thousands of years. Fig. 1. Fossil pupal cases from the Bridgewater Formation resemble small elongated eggs. The cases have a hole where the fossil organism exited. These trace fossils are characterized by their strong cementation and a hollow interior. Scale in mm. (Specimen from the S W Veatch collection. Photo by S W Veatch.) These cases are thought to have contained the pupae Leptopius duponti, a medium-size, soil-inhabiting weevil or snout beetle of the family Curculionidae. The Curculionidae are one of the largest families of organisms, with at least 44,000 described species (Grimaldi and Engel, 2005). Adults of most species of this family have a characteristic elongate snout or nostrum. At the end of this well-developed snout is a small pair of mandibles for biting and chewing food. Taxonomic Classification:KingdomAnimaliaPhylumArthropodaClassInsectaOrderColeopteraSuborderPolyphagaSuperfamilyCurculionoideaFamilyCurculionidaeSubfamilyLeptopiinaeGenusLeptopiusSpeciesdupontiThe adult female Leptopius duponti not only relishes the foliage of … Read More
Neale Monks (UK) In first part of this two part series (Rummages through the core collection of British cephalopods (Part 1)), we looked at some of those British ammonites and belemnites that you’re likely to have in your collection. As we saw, even the most familiar species can have mysteries surrounding them, particularly with regard to things like diet and swimming abilities. But, if you’re a fan of ammonites and their relatives, there’s a good chance you’ve picked up some specimens from other parts of the world as well. Indeed, one of the most remarkable things about ammonites in particular is how widespread some species are, which has made them among the most important groups for biostratigraphy. Put simply, biostratigraphy is the art of using fossils common to two or more geological formations to demonstrate the fact that they were deposited at the same time. Ammonites Being distinctive in shape and often very common, ammonites were among the first fossils to be used for biostratigraphy and identifying ammonite species from different deposits was pretty much all people did with them. Understanding them as living creatures was a minority pursuit until relatively recently and, to be fair, ammonites have proven to be quite difficult fossils to explain. Unlike, say, dinosaur or fish bones, ammonite shells tell us relatively little about what the muscles and others soft parts looked like. In some ways, ammonite shells are like sharks’ teeth — abundant and very varied, but only very narrowly informative. It is generally … Read More
Dr Neale Monks (UK) The Gault Clay is an Albian (Lower Cretaceous) deposit of blue-grey clay exposed primarily in Southeast England. At the classic exposure at Copt Point, Folkestone, the Gault Clay is sandwiched between the Lower Greensand underneath and the Upper Greensand on top. Fig. 1. Folkestone is the most productive location for collecting Gault Clay fossils in the UK. It is a stiff clay that preserves fossils extremely well. In particular, aragonite is sometimes preserved on fossils such as bivalves and ammonites, resulting in much more attractive and detailed fossils than those found in limestone or chalk. As well as providing excellent preservation, the Gault Clay is highly fossiliferous at many localities. Unsurprisingly, these two factors have ensured that the Gault Clay has always been extremely popular with fossil collectors. In terms of what was going on during the Albian, the Gault Clay represents a phase of sea level rise, something known as a “marine transgression”. Compared with the preceding Lower Greensand, this clay was deposited in a deeper, less energetic environment in what is sometimes known as the “Gault Sea”. This was a shallow, warm sea with a muddy bottom. Corals were notably absent, but animals that were adapted to muddy conditions, such as clams and pelican’s foot snails, were common. The sediment particles were finer and less disturbed by water currents and benthic animals (that is, animals living on the sea bottom), resulting in the high-quality fossils so characteristic of this deposit. At this time, the … Read More
Neale Monks (UK) Alongside trilobites, ammonites are by far the most popular invertebrate fossils. Whether you’re an enthusiastic fieldworker or more of an armchair geologist, chances are that your collection includes a fair number of ammonites of one sort or another. These may well have names and localities, but details on the ecology of ammonites is often lacking, and relatively few popular books on geology say much about how ammonites lived beyond the fact they were marine invertebrates related to modern squids and octopuses. As it happens, British geologists are well served when it comes to ammonites, with extensive exposures of Jurassic and Cretaceous strata accessible across the country, from the Kent coast to the Isle of Skye. Coastal exposures are the ideal, of course, but old quarries and other inland sites can be fruitful too, and the UKGE website is there to help anyone wanting to build up their own ammonite collection (see https://www.ukge.com/). Belemnites are often found alongside ammonites, and being cephalopods as well, resembled ammonites in many ways. The biggest difference was that they were more squid-shaped animals, with the buoyant shell inside the animal instead of outside. They were probably quite good swimmers, but whether they foraged close to the seafloor like cuttlefish, or high up the water column like squid, remains unclear. It may well be that different belemnites did different things, and the variation we see in belemnite fossils reflects this. But what, if anything, is the quintessential British ammonite? And if such a … Read More
Neale Monks (UK) Modern brachiopods are rather obscure animals and even their (supposed) common name, ‘lamp shells’, means little to the average amateur naturalist. However, geologists will be much more familiar with them, because brachiopods are among the commonest fossils in sediments of Palaeozoic age, almost right the way through from the Middle Cambrian to the Late Permian. They were sometimes abundant in the Mesozoic as well, particularly during the Jurassic, and may be quite common in some Cainozoic sediments too. But, on the whole, their post-Permian history was one of decline to a role in marine ecosystems far below that of, say, bivalve molluscs or crustaceans. Having said that, brachiopods have always fascinated me because they were survivors. Unlike so many of the superstar fossil groups, like trilobites and ammonites, brachiopods declined but they did not die out. They are not particularly diverse today, but the 350 or so modern species is not a bad tally, and they can be found in all the world’s oceans, from Scottish sea-lochs to the coast of California, from Hong Kong harbour to the rocky shores of Patagonia. They may be bit-part players in contemporary marine ecosystems, but, in their own way, they seem to be very good at what they do, more than holding their own in seas and oceans dramatically different to the Cambrian ones, where they first evolved. While studying for my degree at Aberdeen, I was lucky enough to do a small research project on a modern brachiopod species, … Read More
Robyn Molan (Australia) Fig. 1. The location of the excavations. In an article in the Australian Age of Dinosaurs Journal (Issue 6, 2008) I dubbed the period between 1984 and 1994 ‘a decade of dedication’, thanks to the persistence of an American-Australian team headed by palaeontologists Tom Rich and his wife, Pat Vickers-Rich. (Tom wrote an article for Issue 16 of Deposits, entitled Tunnelling for dinosaurs in the High Arctic.) This was the decade that brought to the world the fascinating polar dinosaurs of south-eastern Australia and the eventual naming of three new dinosaur species – with a few other surprises along the way. Two hundred and twenty kilometres west of Melbourne, on the Otway Coast of Victoria, Australia, is a remote and little-known inlet. Set in a stretch of steep, rugged shoreline, this isolated cove is pounded by the Southern Ocean and blasted by Antarctic winds. Nearby, the world-renowned rocky sentinels, ‘The Twelve Apostles’ (see the cover of Issue 20 of Deposits), stand testament to the power of wave and wind, as they beckon tourists who travel the Great Ocean Road. Fig. 2. The rugged beauty of Dinosaur Cove. (Photo Ros Poole.) The excavation at Dinosaur Cove, as the inlet later became known, was the first major dinosaur dig conducted in Victoria. For several weeks each summer, the Rich family, and a crew of hardy volunteers, battled untold obstacles to wrestle fossils from the base of the cliff. It was gruelling, dirty and dangerous work, but subsequent scientific research … Read More
Dr Thomas H Rich (Australia) Fig. 1. Location of the Liscomb Bonebed. (© Thomas Rich.) I have no idea what made me look up at that moment. But, when I did, I saw a flash of light reminiscent of the sun glinting off the wings of a flock of birds abruptly and simultaneously changing direction. However, the light was not from a flock of birds. Rather, it was from thousands of individual, fist-sized lumps of rock, together with lumps of half-frozen mud on the steep slope above me. They were glistening due to a film of meltwater covering them and they were simultaneously starting to roll because the tonnes of rock on which they lay had suddenly started to collapse and plummet down towards me on a journey that would end in the frigid waters just below my feet. At that moment, I was digging into permafrost at the base of the steep slope forming the left bank of the Colville River that flows across the North Slope of Alaska and terminates in the Arctic Ocean about 40km further downstream. (The North Slope is the tundra covered coastal plain in northernmost Alaska bordered on the north by the Arctic Ocean and 250km to the south by the east-west Brooks Range.) Like my companions, my efforts were directed towards recovering ‘polar dinosaurs’, at a locality named the Liscomb Bonebed in honour of the geologist who found it in 1961. Fortunately, the tonnes of mud and claystone that cascaded down the bank … Read More
Michał Zatoń, Adrian Szewczuk and Mirosława Kuziomko-Szewczuk (Poland) Skeletons of live and dead marine animals very often serve as a secondary hard substrate for various organisms that either encrust it (encrusters) or bore into it (borers). The terminology for encrusters and borers varies. However, following Paul Taylor and Mark Wilson’s latest and widely accepted terminology for organisms inhabiting hard substrate, those associated with skeletal substrates should be referred to as episkeletobionts and endoskeletobionts, respectively. Another, more convenient term is ‘sclerobionts’, as it refers to any organisms (encrusters or borers) inhabiting any hard substrate (biogenic or lithic, including skeletons of both live and dead organisms). Sclerobionts are diverse in marine ecosystems today, being represented by such various groups as sponges, corals, bivalves, polychaetes, bryozoans and brachiopods. They were also diverse in the past, being represented by different taxa during different epochs. And like today, they inhabited various kind of hard substrate, such as stones, shells and reefs, creating specific benthic communities that changed and evolved over time. Sclerobiotic assemblages are also very useful in ecological studies. As encrusters firmly adhere or cement to, and borers drill into, the substrates they colonise, they are always found as fossils where they had actually colonised. And as they play a crucial role in ecosystems, being both constructive (for example, as a component of reef frame-builders – the so called ‘binders’) and destructive (for example, as reef bio-eroders), there is a growing scientific interest in their ecology, which focuses on both Recent and past environments. … Read More