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Book review: The Lewisian: Britain’s oldest rocks, by Graham Park

Recently, I have finished the Great Silurian Controversy, a magnificent book about the nineteenth century arguments over the age of the lower Palaeozoic greywackes/sediments of Devon, and the creation of the concept of the Devonian. And reading The Lewisian: Britain’s oldest rocks by Graham Park, perhaps it occurs to me that this should perhaps be called, The Great Lewisian Controversy. It shares the same historical and scientific intentions, and the same grand sweep of scientific history from the early twentieth century, namely, the exploration over decades of the geology of the Lewisian of northwest Scotland.

Shetland – an archipelago on the edge

Allen Fraser (UK) Shetland is a spectacular group of islands with a varied geology, a wonderful landscape and a special flora and fauna, peopled by a culture distinct within the British Isles. Shetland remains one of Britain’s natural treasures.” (J. Laughton Johnston) Fig. 1. St Ninian’s Isle. The islands Shetland sits on the edge of the European continental shelf and is sinking. Since the end of the last glaciation about 10,000 years ago, relative sea level has risen by about 120m and has fashioned an archipelago of over 100 islands. The island group extends over a distance of 110km from Muckle Flugga (Fig. 2) in the north to Fair Isle in the south, and a convoluted coastline, over 2,700km in length, means that no point on land here is more than 5km from the sea. Fig. 2. Muckle Flugga, a small rocky island north of Unst in the Shetland Islands. The landmasses of the larger islands are generally in the form of roughly north-south ridges of hills forming the ‘spine’ of Shetland. The hills, mainly composed of acidic granite, schists and gneisses, are treeless and are generally covered by peat or blanket bog. The valley floors between the hills of the central Mainland (the largest island) are composed of crystalline limestone and are generally more fertile. Together with sandy coastal areas, they form the best agricultural land. Fig. 3. The fertile valley of Tingwall. Fig. 4. The port of Scalloway, the largest settlement on the west coast of the Mainland, … Read More

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Conulariids: fossilised jellyfish

Maria C Sendino and Paul D Taylor (UK) Fossils such as ammonites, trilobites, crinoids and shark’s teeth understandably attract the most attention from fossil enthusiasts. However, other groups can provide equally fascinating insights into the history of life and ought not to be neglected. Among these ‘Cinderella fossils’ are conulariids. Found in late Precambrian (Ediacaran) to Triassic marine deposits, conulariids survived for more than 350ma, disappearing about 200 million years ago, at a time when the continents were clustered together into a huge landmass called Pangaea. However, they are most common in Middle Ordovician to Permian rocks. Almost 400 species of conulariids have been described from around the world, and in some places they are abundant enough to lend their name to particular geological units, for example the Conularia-Sandstone in the Upper Ordovician of Jordan. Fig. 1. A species of Conularia from the Lower Carboniferous of Indiana showing the aperture closed by lappets. Affinities What are conulariids? Initially, they were thought to be molluscs because of their pyramidal-cone shape that is vaguely reminiscent of a straight nautiloid. Others believed them to be worm tubes. For a long time they were classified as ‘Problematica’, which is a formal way of admitting total ignorance about their affinities. They have also been placed in a phylum of their own, the Conulariida. This uncertainty results from the lack of preserved soft parts. However, strong evidence has emerged in recent years showing that conulariids belong to the same class – Scyphozoa – as jellyfish and … Read More

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The British Carboniferous Limestone

Neale Monks (UK) The rocks we know in Britain and Ireland as the Carboniferous Limestone were laid down between 363 and 325 million years ago, during a period when global sea levels were particularly high, a condition that geologists refer to as a transgression. The climate was tropical, and the warm, shallow seas that covered much of the British Isles teemed with life. Consequently, the Carboniferous Limestone is often highly fossiliferous, and good exposures can yield vast numbers of crinoids, brachiopods, corals, bryozoans and other types of marine fossil. Despite being known as the Carboniferous Limestone, one thing notably absent from this formation is coal. Coal is made from the fossilised remains of trees, and the forests and freshwater swamps where those trees grew could only develop once sea level had dropped. Coal-bearing sediments weren’t laid down until the second half of the Carboniferous Period, when sea level was relatively low. International stratigraphyThe International Commission on Stratigraphy refers to the interval of time between 359 and 299 million years ago as the Carboniferous Period, but, historically American geologists recognised two periods instead: the Pennsylvanian and the Mississippian. These were roughly equivalent to what geologists elsewhere considered the Lower and Upper Carboniferous, so the ICS has standardised the Pennsylvanian and Mississippian as the two epochs within the Carboniferous. However, it isn’t quite as simple as sea level dropping in the middle of the Carboniferous and all the subsequent sediments of the period being terrestrial in nature. What tended to happen was … Read More

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Gigantic rhizodonts in Scotland’s lochs: The one that got away

James O’Donoghue (UK) Fig. 1. If gigantic rhizodonts still lurked in Scotland’s lochs, anglers might find they are biting off more than they can chew. (Illustration by Megan Whatley.) Every angler dreams of reeling in a prize catch – a 40lb pike perhaps, or a whopper of a salmon. Record-breaking fish fire the imagination as few other creatures can, and the lochs of Scotland have inspired many a fishy tale. However, even the tallest of these stories pale into insignificance when compared with the primeval occupants of the lochs. Had you cast a line there 340 million year ago, you could have ended up as bait yourself. For Scotland’s ancient lakes and rivers held a behemoth of a fish known as Rhizodus hibberti (Fig. 2), which notched up a truly staggering snout-to-tail length of seven metres. It was the ultimate ‘one that got away’, a predator that was half as big again as a great white shark. To this day, it remains the largest freshwater fish ever to have lived. Rhizodonts, the group of fishes to which R. hibberti belonged, may have been the last truly gigantic predators to live in fresh water, suggests palaeontologist Jon Jeffery, an expert on one of the most widely distributed species, Strepsodus. They also have the distinction of being the most primitive ‘tetrapodomorphs’ known. That is, they belong to the group of fishes from which tetrapods descended. Tetrapods are vertebrates that colonised land and includes all amphibians, reptiles, birds and mammals. Fig. 2. Jaw … Read More

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Geology museums of Britain: The Hunterian, Glasgow

Jon Trevelyan (UK) This is the second of my articles on the geology museums of Glasgow (see also Geology museums of Britain: Kelvingrove Art Gallery and Museum, Glasgow). The Hunterian contains for some Scotland’s finest collections, covering subjects such as Roman artefacts from the Antonine Wall (fascinating, given that its big, southern, brother – Hadrian’s Wall – gets all the attention), and scientific instruments used by eminent Scottish scientists, James Watt, Joseph Lister and Lord Kelvin. In fact, the Hunterian’s whole collection is ‘Recognised’ as nationally significant in Scotland. It is also home to one of the most distinguished public art collections in Scotland. However, as always, it was the geology and palaeontology that I went to visit (Fig. 1). Fig. 1. The hall of the museum, with the geology and palaeontology exhibits set out below. The Hunterian’s founding collection came through the bequest of the eponymous Dr William Hunter (1718-1783). The museum itself opened in 1807, and a catalogue was published in 1813 (Fig. 2) by Captain John Laskey, who took visitors through the museum room by room and case by case, describing the items on display. Fig. 2. The catalogue of the original museum contents, by Captain John Laskey, with a lovely shark’s tooth from the original collection. And, apparently, the fossil collections are among the largest in the UK and were built up over the last 200 years from departmental research and teaching collections. Fig. 3. Ripple marks covered in trace fossils. Fig. 4. Copious fossils on … Read More

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Geology museums of Britain: Kelvingrove Art Gallery and Museum, Glasgow

Jon Trevelyan (UK) When I went up to Glasgow to attend my son’s graduation, I deliberately made some time to visit Kelvingrove Art Gallery and Museum to explore its 22 galleries. These cover everything from art to animals, Ancient Egypt to Charles Rennie Mackintosh and much, much more besides. However, the reason why I am including Kelvingrove in my series covering the geology museums of Britain, and the real reason for my visit, is its gorgeous collection of fossils, in particular, significant ones found from Scotland and, indeed, in and around Glasgow. Located in the beautiful Kelvingrove Park (Fig. 1), the art gallery and museum opened in 1901 and is clearly a firm favourite with local people and visitors. It has stunning architecture (Fig. 2) and a family friendly atmosphere; and has relatively recently been redesigned – without losing its Victorian traditions and ideals – so that it is upgraded for the twenty-first century. Fig. 1. The museum is located in Kelvingrove Park, which necessitates a lovely walk through the grounds of this Victorian, public park. Fig. 2. The magnificent frontage of Kelvingrove Art Gallery and Museum. In fact, Kelvingrove started life as typical Victorian museum (Fig. 3), founded by (as the guide puts it): … the wealthy classes to assert their cultural worth and improve the people of the city”. Fig. 3. The roof of the Victorian entrance hall. However, as I say, there have been improvements, which were achieved by asking Glasgow residents what they approved of the … Read More

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Fenestella and other bryozoans in the Carboniferous rocks of the British Isles

Paul D Taylor (UK) Ask a geologist to name a fossil bryozoan found in the rocks of the British Isles and the most likely answer will be Fenestella. The net-like fossils of Fenestella are especially abundant in the Carboniferous Limestone (Figs 1 and 2), although the genus, as used in its broadest sense, is also present in the Silurian, Devonian and Permian deposits of Britain. Fig. 1. Colony of Fenestella (s.l.) nodulosa from the Lower Carboniferous of Calcot Quarry, Halkyn Mountain, Flintshire. Branches forming the characteristic meshwork fan outwards from the colony origin. Fig. 2. Large colony of Fenestella (s.l.) flabellata from the Carboniferous Limestone of Fife in Scotland. Fracturing of the meshwork is evident. While Fenestella dominates almost all bryozoan assemblages found in the British Carboniferous, a variety of other bryozoans are commonly found. Some Carboniferous bryozoans inhabited reefs or mounds, others were components of non-reef marine communities where they lived together with brachiopods, crinoids and corals at a time when the British Isles was situated close to the equator. All Carboniferous bryozoans constructed immobile colonies consisting of numerous individual zooids, with crowns of tentacles used to capture tiny planktonic algae floating in the water around. Our knowledge of the diversity of Carboniferous bryozoans in the British Isles has increased enormously during the last 50 years through the studies of David E Owen, Ron Tavener-Smith, Adrian J Bancroft and Patrick N Wyse Jackson. Yet, and in common with bryozoans from other geological periods, Carboniferous bryozoans are too often perceived … Read More

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The Elgin Marvels

By Neil Clark (UK) Not to be confused with the Elgin Marbles, the Elgin Marvels actually come from the Elgin area of Scotland. They are well known fossil reptiles and their footprints, of Permo-triassic age, that were collected from old sandstone quarries mostly over a century ago. They are partly what inspired me to take up palaeontology although, at that time, I had never actually been to Elgin, nor ever seen the fossils. It was through the lectures of Professor Euan Clarkson of Edinburgh University in the 1980s that I first became aware of these animals. However, it was not until much later that I came face to face with the Elgin Marvels themselves. Sketch map of the geology around Elgin. In the summer of 1996, while recovering from a broken leg as a result of dinosaur hunting on the Isle of Skye (see my article in Issue 12 of Deposits), I was asked to give a talk on my exploits at an Open University Summer School in Edinburgh. Most of the talk was concerned with the study of dinosaur footprints, their interpretation and identification. After the lecture, I joined the students in their usual nocturnal social discussion groups. It was at this time that I was approached by one of the students who claimed to have seen some ancient footprints in the bedded sandstones near Elgin. The student, Carol Hopkins, invited me to Elgin to have a look at the footprints she had found. I could not pass up … Read More

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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.

Book review: Fossils of the Kimmeridge Clay Formation (Palaeontological Association Field Guide to Fossils No 16), edited by David M Martill and Steve Etches (pictures editor, Robert F Loveridge)

I always wait expectantly for the publication of a new Palaeontological Association guide to fossils and, when they turn up, I am never disappointed. This is undoubtedly another triumph. This guide attempts to bring the diversity of its flora and fauna together in a single work, for the first time.

Book review: Measures for Measure: Geology and the Industrial Revolution, by Mike Leeder

I sat down to read this over Christmas and what a good read it turned out to be. The appropriate word is ‘eclectic’ – because Measures for Measure is written for all us with an interest in the industrial history of Great Britain, and its impact on the landscape, economy, social history and culture. It’s a great read as it dots about linking places and ideas together, with the link always being the geology.

Book review: Strata: William Smith’s Geological Maps, with contributions by Oxford University Museum of Natural History, with a foreword by Robert Macfarlane

This book is truly sumptuous, and yet is also a comprehensive discussion of William Smith’s maps (including the revolutionary ‘A Delineation of the Strata of England and Wales, with part of Scotland’) and career. It is beautifully produced, printed on quality paper and the full colour illustrations are outstanding.

On the origins of buffalo wings and chicken fingers by means of unnatural connexion, or the preservation of flavoured races in the struggle for clarity

Carl Mehling (USA) Things aren’t always what they seem. The fluidity of information and the frailties of human memory allow for a lot of corruption. Innocent assumptions are made. Sloppy mistakes take place. Unforeseeable accidents occur. And deliberate subterfuge is always there as an option when these others fail. Throw … Read More

Book review: Hutton’s Arse: 3 billion years of extraordinary geology in Scotland’s Northern Highlands (2nd edition), by Malcolm Rider and Peter Harrison

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.

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. … Read More