Rudists: A fossil story

Jack Shimon (USA) This article is adapted from a presentation given at the Denver Gem Show, September 17, 2016 by me, Jack Shimon. When I was six and a half years old, my Grandpa took me fossil hunting in central Texas. We went to a Carboniferous Limestone quarry that he had visited earlier and was given permission to enter and collect from. This was one of my first fossil hunting trips and I really enjoyed it. The ancient reef we went to (now a quarry) had huge boulders of limestone and tube-like things in it we later to be found to be rudist bivalves. This article is all about these finds and the efforts we went to, to find out what they were. Fig 1. The author at the quarry. (Photo credit: Mike Hursey.) Fig. 2. This Google satellite image shows the reef we collected from. Two of the three lobes have been excavated for limestone. You can also see smaller pinnacle reefs marked with the short arrows. All of the reefs rise above the flat Texas landscape. (Permission from Google.com: ‘Special Use Guidelines’.)Fossils We spent a lot of time at the quarry observing the massive specimens onsite and then collected some smaller pieces to bring home and look at closer. A simple way of thinking about fossils is to consider them either as a cast or a mould. A mould is formed when an object is placed into a soft substrate and then decomposes or is washed away leaving … Read More

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Tully Monster: Is this the world’s most mysterious fossil?

James O’Donoghue (UK) The Tully Monster is a mysterious 307Ma-old marine animal known only from the famous Mazon Creek fossil locality in Illinois. Its body plan is unlike any other animal that has ever lived, and it has been subject to wildly different interpretations as to its identity since its discovery in 1955. Last year, Victoria McCoy of Yale University and colleagues identified it as a lamprey, a primitive type of fish, but this has since been challenged by a team of vertebrate palaeontologists. Fig. 1. Reconstruction of a Tully monster based on the research of McCoy and colleagues. The claw and proboscis are on the right and its eyebar and eyes, gills and tail fin are further back. (Sean McMahon/Yale University.) Fossil collector Francis Tully knew he had made an extraordinary discovery. Inside a rounded nodule was a bizarre, foot-long animal with a long trunk and claw. But he could never have known quite how extraordinary his 307Ma-old fossil would turn out to be. Sixty two years later, scientists are still arguing over the basics as to what sort of creature it really was. What makes it even stranger is that this is no rarity known only from fragmentary remains. After Tully made his find, word got around among collectors and, before long, hundreds more had been found. Tullimonstrum gregarium, or ‘Tully’s common monster’, is now known from well over a thousand fossils, including many complete specimens. “We’ve got four cabinets of Tully monsters here, each of which has … Read More

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Fossil folklore: Fish

Paul D Taylor and Mike Smith (UK) Fish are the most diverse animals with backbones – that is, vertebrates – living today. Bone and teeth of fishes abound in the fossil record, from the armour-plated, primitive fishes of the Devonian, through the cartilaginous sharks with their shiny dagger-like teeth, to the bones of advanced ray-finned teleosts related to modern carp and cod. Along with other marine fossils, fossil fishes were once used as ‘proof’ of the biblical deluge, for example, the fabulous Cretaceous fossil fish deposits of Lebanon. Gayet et al. (2012) recorded that, in the third century, the Bishop of Palestine wrote: “That Noah’s Flood covered the highest mountains is for me the truth, and I say that the witness of my eyes confirms it: for I have seen certain fishes, which were found in my lifetime on the highest peaks in Lebanon. They took stones from there for construction, and discovered many kinds of sea fishes which were held together in the quarry with mud, and as if pickled in brine were preserved until our times, so that the mere sight of them should testify to the truth of Noah’s Flood”. Petrified nails Hugh Miller, in his book Foot-prints of the Creator (Miller, 1849), mentioned that amateur geologists of Caithness and Orkney would refer to one particular fossil in the Old Red Sandstone, presumably relatively common, as ‘petrified nails’ (Fig. 1). Fig. 1. A so-called ‘petrified nail’, about 150mm long, as depicted by Hugh Miller. These fossils represent … Read More

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