Concretions in sandstones of the Inner Hebrides, Scotland

Mark Wilkinson (UK) Concretions are a common feature in many sedimentary rocks, yet they seem sometimes to be misunderstood. So, how do concretions form? As well-studied examples, let’s look at the ones found in some of the sandstones of the Scottish Inner Hebrides, notably the islands of Eigg and Skye. The concretions are found in several formations, but perhaps the largest and most spectacular are in the Valtos Sandstone Formation of the Great Estuarine Group. This was originally named the Concretionary Sandstone Series after the prominent metre-scale concretions. It is Bathonian in age (Middle Jurassic) and is interpreted as having been deposited in a coastal environment. The Great Estuarine Group is becoming famous for its abundant dinosaur footprints and much rarer skeletal material. The concretions themselves vary from spherical to elongate volumes of rock and are typically from around 50cm to one metre or more in diameter. They are also often coalesced into groups (Fig. 1). Inside the concretions, the spaces between the sand grains are filled completely with a calcite cement. The concretions are resistant to weathering compared to the host sandstone, which is fairly soft, so stick out from the cliff in a sometimes rather alarming manner as you walk below them. I’ve been visiting the concretions sporadically for around 30 years and some of the ones that I photographed in the cliffs in the 1980s are now lying loose on the beach. None of them have fallen while I’ve been there, touch wood. Fig 1. Concretions on … Read More

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Saltwick Bay, North Yorkshire

Emily Swaby (UK) Saltwick Bay is located along the Yorkshire Coast, between Whitby and Robin Hood’s Bay, and can be accessed from the Cleveland Way, which passes the spectacular Whitby Abbey. The geology of the area is predominantly Jurassic in age, with the site often being described as a ‘fossil treasure trove’. The bay yields a wide variety of specimens, including common ammonites and belemnites to rarer finds such as marine reptiles, Whitby Jet and even dinosaur footprints. Even though Saltwick Bay is close to Whitby, it is still a very productive locality and you never leave empty handed. In fact, it is a good location for families and beginners. The walk to Saltwick Bay from Whitby itself is approximately 2.4km and provides many picturesque views of the abbey, the harbour entrance and the remarkable coastline. The steps leading down to the beach are located just past Whitby Holiday Park, but can sometimes be slippery during winter months. It is also recommended that you check tide times for the area before arriving, as high tide can limit the extent of accessibility and could potentially cut you off. Fig. 1. The steps descending down the cliff to the bay. Once you have made your way down the steps, fossils can be found immediately among the scree or in the shingle. However, it is advisable stay away from the base of the cliffs, as rock falls are common, with loose fragments of shale constantly falling down. Fig. 2. The Nab is a … Read More

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Discovering dinosaurs in Britain: The significance of the British dinosaur record

Dean R Lomax (UK) Palaeontology and Britain In its simplest form, palaeontology is the study of prehistoric life, through examination of fossils. Palaeontology is, however, not just dinosaurs. Dinosaurs constitute a miniscule portion of what palaeontology is. After all, a myriad of different, and often down-right bizarre, organisms lived long before the dinosaurs and ended up as fossils under their feet. Regardless, the imagination and wonderment that dinosaurs create are why they are considered a symbol for palaeontology – they are a gateway into this most incredible of sciences. The geology and palaeontology in Britain is incredibly diverse. Rocks of almost every geological period are exposed and have been studied for hundreds of years. This provided a platform for geology and palaeontology to flourish and evolve. Some rather notable individuals include the geologist, William Smith – the ‘Father of Geology’. In 1815, Smith created the very first geological map of England, Wales and part of Scotland, a ground-breaking achievement. Incredible fossil discoveries found along the beach at Lyme Regis, by the greatest fossil hunter ever, Mary Anning, paved the way for the first scientific descriptions of large, extinct reptiles – the ichthyosaurs and plesiosaurs. The Rev William Buckland provided the very first scientific description of a dinosaur – this would change the world. Fig. 1. The author pictured with dinosaur footprints at Hanover Point, Brook, Isle of Wight (2014). Our fascination and intrigue in studying and examining the rocks and fossils within has unlocked an ancient, alien world. If you … Read More

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Fleshing-out a dinosaur-eating snake

Tyler Keillor (USA) In the March 2010 issue of the open-access journal, PLoS Biology, palaeontologist Jeff Wilson and colleagues give an account of a truly unique and amazing fossil discovery. In their article entitled Predation upon Hatchling Dinosaurs by a New Snake from the Late Cretaceous of India, the snake Sanajeh indicus is described, based upon multiple specimens. In particular, one snake fossil was found in a nest of sauropod eggs, looped around a crushed egg, with hatchling sauropod bones next to the broken egg. The very moment of predation seems to have been preserved in rock, as a sudden plug of sand from a flash flood smothered the animals, preserving them for millions of years. Fig. 1. Small-scale maquette to help visualise and plan reconstructing the scene at full scale. The sediment analysis hadn’t been completed at this stage, so vegetation tentatively filled the nest in early mock-ups. Jeff contacted me about creating a reconstruction of this fossilised scene ‘in the flesh’ as a display. I had previously collaborated with him while he and Paul Sereno were studying the bizarre African sauropod, Nigersaurus taqueti, at the University of Chicago’s Fossil Laboratory. For that project, I created a restored skull model of the dinosaur for its unveiling, as well as a life-sized flesh model of the head and neck. These models are an extremely effective, visual means of conveying new discoveries to the public. The value of a model is underscored when a fossil isn’t very photogenic or might otherwise … Read More

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