Gravel sheets in the suburbs of Washington, DC

Deborah Painter (USA) If you live in western Prince George’s County, Maryland in the USA, in the towns of Oxon Hill and Suitland and you want to dig to place a water line, plant a garden or excavate to construct a foundation for any building, chances are you will encounter sandy soil with hundreds of cobbles and boulders. Some boulders encountered could be in the form of large flattened slabs. You might be wondering why these are present, since these towns are in a coastal plain, far south and east of the rocky outcrops of the Piedmont area of Virginia and Maryland. For someone like me, who was born and raised in the Coastal Plain area of Virginia, these ubiquitous cobbles and boulders seemed out of character for the region. I discovered these odd boulders and cobbles when I joined a colleague from an office in a northern state to assist him in ecological studies for two small sites not too far from the United States Capital of Washington, in the District of Columbia (DC). Our goal was to help our client know if there were any threatened or endangered species, wetlands, hazardous materials or other site constraints, as this would assist the client to decide whether to purchase the properties. Our first Prince George’s County site for an ecological study was one of a few hectares in size in Suitland, a suburb of Washington, DC and approximately 8km southeast of the border of the capital city near the shore … Read More

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La Gomera: A short geological guide

Ken Madrell (UK) The island of La Gomera has an area of 370km2, it is 25km in diameter, has a maximum altitude of 1,487m (Alto Garajonay) and is situated approximately 40km west of Tenerife. Unlike the other Canary Islands, La Gomera has experienced a long and continuing eruptive break and is in a ‘postshield erosional stage’. Carracedo and Troll (2016) describe this as the stage when active volcanism has ceased, and erosive and denudational landforms are predominant (p. 39). The submarine base of the island shows that it rests on a shallower ocean bed than the surrounding islands. The emerged land mass is semi-circular in shape, with a radial drainage pattern from its centre near Alto de Garajonay. The dating of the island has proved problematic, as some of the earlier measurements placing its age between 15 Ma and 19 Ma have since proved to be inaccurate. More reliable estimates now put its age at between 10 and 11 Ma. Fig. 1. Roque Argando viewed from Lomo de la Mulata. La Gomera’s general stratigraphy comprises of three main rock sequences: A Miocene basaltic shield, including a basal plutonic complex (that is igneous rock formed by solidification at considerable depth beneath the earth’s surface).A nested felsic (that is, igneous rocks that are relatively rich in elements that form feldspar and quartz) stratovolcano (which is built up of alternating layers of lava and ash).The youngest Pliocene volcanism.Fig. 2. Sketch map of La Gomera, showing the main towns and geology of the island. … Read More

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Boxstones: In search of Miocene Suffolk

Tim Holt-Wilson (UK) The date is 24 May 2014 and I am browsing across East Lane Beach at Bawdsey in southeast Suffolk. A brown lump of sandstone with a white fossil shell impression catches my eye. A boxstone. This is the first one I have ever found with a fossil in it. Looking closely, I see that the sea has abraded the shell’s outlines, although the margins have survived better than the rest, so it should be possible to identify the specimen (Fig. 1). Fig. 1. Boxstone, found 24 May 2014. Boxstones are fragments of a vanished world. They are all that remains of a lost geological stratum in Suffolk called the ‘Trimley Sands’ (Balson, 1990), although deposits of similar age are still present across the sea in Belgium and other parts of Europe. Boxstones are lumps or concretions of brown sandstone, which may contain shell fossils and – if you are extremely lucky – bones and teeth. They are beach-rolled and rounded, and typically measure between 5 and 15cm in diameter. The sand is mostly quartzose, with a rich assemblage of secondary minerals, and is cemented with carbonate-fluorapatite (a phosphate mineral) and calcite (Mathers and Smith, 2002). Boxstones can be found scattered sparsely across the shingle beaches at Bawdsey and Felixstowe Ferry (Fig. 2), and in situ as a common component of the basement beds (nodule beds) at the base of the Coralline Crag and Red Crag formations of southeast Suffolk (Fig. 3). They are eroding out of the … Read More

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New museum in northern Greece: The Siatista Historical Paleontological Collection, the first record of a stegodon in Europe and the making of the straight-tusked elephant

Dick Mol (The Netherlands), Evangelia Tsoukala (Greece), Evangelos Vlachos (Greece), Anna Batsi (Greece), Hans Wildschut (The Netherlands), Dimitra Labretsa (Greece) and Wilrie van Logchem (The Netherlands) The Historical Palaeontological Collection of Siatista (HPCS), housed in a school building in Siatista, Kozani, Macedonia in Greece, was studied by the authors during the summer of 2009. The collection was assembled by local people from 1902 onwards, under the initiative of Nikolaos Diamantopoulos. Anastasios Danas, a high school teacher at the Trampantzeion Gymnasium in Siatista, was the main collector and he founded the Siatista’s palaeontological collection in 1906. The recovered records of the collection are minimal and it is not always clear from which locality the fossils were collected. However, the archived documents indicate that all the fossils were collected in the larger region of Siatista. Fig. 1. Replica of the Pleistocene straight-tusked elephant, Elephas antiquus, the eyecatcher of the Siatista Museum In 1972, Prof Ioannis Melentis, famous for his studies and publications on the fossil proboscideans of Greece, realised the importance of the collection and, in 1980, he became involved in the study and management of the collection, which was officially donated to the community of Siatista in 1994. The first exhibition was held in the Trampantzeion in 1982. In 2011, the collection was put on display in this beautiful building in Siatista, which was built in 1888. In a short time, it became one of the attractions of Siatista, telling the story of the large pachyderms that once roamed the northern … Read More

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West Coast Fossil Park, Western Cape, South Africa

Margaret A Dale (UK) While planning a touring holiday, which encompassed part of the west coast of South Africa, I spotted the words “fossil park” on the map, about 150km north of Cape Town, some distance from a village called Langebaanweg. Intrigued to find out more, I searched the Internet to determine if it was accessible to the public and, if so, its opening times. I found nothing. Not to be deterred, my husband and I decided that, once we were in the country, the usual tourist literature would give us the required information. Unfortunately, once again, there was nothing. So, determined not to be defeated, we drove to the area in the hope we could find it and visit it. Fortunately, we managed both. The fossils in the park date back to the late Miocene and early Pliocene eras (Fig. 1). These are important periods in human evolution, since it is believed that the last common ancestor of humans and our closest living relatives – chimpanzees – lived during this period. Mio-Pliocene hominid fossils are extremely rare and have only ever been found in East Africa and not among the deposits found at the West Coast Fossil Park to date. Fig. 1. One of the many partly excavated fossil beds. With more than 200 different kinds of animals being identified, the park possibly represents: The greatest diversity of 5 to 5.2myr-old animal fossils found anywhere in the world; andThe richest fossil bird site older than 2myrs in the world.The … Read More

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Coping with coprolites

Carl Mehling (USA) Generally, we have no use for it, or at least we convince ourselves we don’t, conveniently ignoring the fact that faeces of one kind or another (even our own) have fertilised our food for millennia. Organic waste products are an integral part of the living system and don’t tend to sit around for long. And it’s a good thing too, because, without the recycling of waste in Nature, we’d certainly be swamped by the stuff. Fig. 1. Ammonnite chamber steinkern composed of tiny invertebrate coprolites (Carl Mehling). Fig. 2. A probable Cretaceous crocodililian coprolites Fig. 3. The real thing? (Carl Mehling). Alas, this is a problem for students of coprolites – those droppings from Deep Time – as it reduces the probability of good coprolite fossils. However, everything in Nature has a story to tell, and there’s usually someone eager to listen, whomever or whatever that storyteller might be. I am one of those palaeontologists drawn to make order out of ordure and, thanks to the whims of the fossil record, enough of these now-inoffensive offerings have fortunately survived to the present. Fig. 4. A Triassic coprolite filled with fish bones (Carl Mehling). My first coprolite emerged from the Late Cretaceous marine sediments of Big Brook, New Jersey. It was a coprolite of spiral morphology – surprisingly common, once one’s search image is tuned – which my mentors credited to a shark. All ‘experts’, both amateur and academic, reflexively parroted this identification. Later, I learned that other … Read More

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