Wooster’s Pseudofossils of the Week: Artifacts in thin-sections of Ordovician limestones from southeastern Minnesota

October 21st, 2016

1bubfirstIt is always exciting to a geologist when thin-sections of curious rocks are completed and ready for view. A thin-section is a wafer of rock (30 microns thick) glues to a glass slide and examined by transmitted light through a petrographic microscope. They provide fantastic views of the mineralogy, paleontology, and structure of a rock in exquisite detail. Thin-sections are also full of mysteries since we have essentially two-dimensional slices through three-dimensional materials.

Thin-sections from the Decorah Formation samples collecting by Team Minnesota this past summer were finally available this week for study. I took the first look at slides of limestones containing ferruginous (iron-rich) ooids we gathered as part of Etienne Fang’s (’17) Independent Study. The first structures I saw were the crazy dark outlines above. What sort of fossils are these, I wondered. Could they be sponges? Odd bryozoans? Borings through the rock fabric? I was ready to post them here as mystery fossils to solicit your opinions. Now, though, they instead make a cautionary tale.

2bub730There are many of these features in a single slide from the Decorah Formation exposed at the Golden Hill outcrop near Rochester, Minnesota. Some are astonishingly complex. It then began to occur to me that these structures were too convoluted and unpredictable to actually be fossils. It also bothered me that to focus on them required to put the rest of the field out of focus. That only made sense if these oddities were in the epoxy, not the rock itself.

3buboverlapEtienne showed me how to demonstrate that these funny loops were not in the rock with this view: You can just make out the greenish lines overlapping the cut surface of this ferruginous ooid. Turns out I was excited about air bubbles in the cementing epoxy. They have nothing to do with the rock. I nearly posted my own pseudofossils.

4trio7321I held out hope, though, that these odd white objects in another thin-section of ooid-rich limestone. They appear to be ghostly outlines of ooids with a finely-textured object inside. They look like seeds with embryos within. Several are scattered through the thin-section. Another mystery fossil!

5duo7321A closer view. Strange how each internal object seems connected to an ooid on the outside, making them asymmetrical in their placements.

6single7321Strange also how once again the details of the internal object can only be seen with the rest of the slide out of focus. Yes, another artifact in the epoxy. This time we may be looking at holes left by ferruginous ooids plucked from the rock through the grinding process, pulling a patch of epoxy with them. Somehow this happened when the now-missing ooid was wedged against another. Nothing to see here, folks.

7ooid7301fAt least I can take the opportunity to show how cool Etienne’s ferruginous ooids are. Note that this one has a greenish layer midway through the cortex. It looks like the mineral chamosite to me. Spectacular detail in the lamellae, but only visible if the image is over-exposed.

8bifoliate7301hThere are plenty of real fossils in these thin-sections, of course. My favorites are these bifoliate bryozoans (lower right half) with their zooecia filled with ferruginous material. Note that the ooid above has had some of its lamellae dissolved away, probably because of some mineral diversity. Also note in the upper right another one of those crazy air bubbles.

The lesson I learn over and over: think, but then think again.




Wooster’s Fossil of the Week: Spiriferinid brachiopod from the Lower Carboniferous of Ohio

October 14th, 2016

syringothyris-texta-hall-1857-anterior-585Sometimes I choose a Fossil of the Week from our Invertebrate Paleontology teaching collection because students have responded to it in some way. This week’s fossil brachiopod has confused my students a bit because it is an internal mold (unusual for brachiopods in our experience) and a member of the Order Spiriferinida rather than the Order Spiriferida. (Catch that? The difference is in two letters.) It is Syringothyris texta (Hall 1857) from a local exposure of the Logan Formation (Lower Carboniferous). Above is a view of the anterior showing the medial fold and sulcus (like an anticline). This, by the way, is the largest brachiopod in our collection.

syringothyris-texta-hall-1857-posterior-585Syringothyris Winchell, 1863, is a genus within the order Spiriferinida, as noted before. This order was erected in 1994, pulling it from the more familiar Order Spiriferida. In this preservation, the spiriferinids are distinguished by a high cardinal area in the posterior (shown above). Not much higher than the spiriferids, truth be told.

syringothyris-texta-hall-1857-dorsal-585This is a view of the dorsal valve side of this internal mold. Note the absence of ribs (plicae) on the fold in the middle.

a_winchellThe geologist and paleontologist Alexander Winchell (1824-1891) named and described the genus Syringothyris. We met Winchell before in this blog as he described many common fossil taxa in the Midwest. He was born in upstate New York, a seventh-generation New Englander. In 1847 he was graduated from Wesleyan University in Connecticut. He had a varied and peripatetic career, spending most of his time as a teacher of science. He first taught in New Jersey, New York and Alabama, staying a short time in each place. He founded the Mesopotamia Female Seminary in Eutaw, Alabama, and became president (briefly) of Masonic University in Selma. In 1854, Winchell was appointed professor of physics and civil engineering at the University of Michigan, a position that soon became geology and paleontology. Five years later he became the state geologist of Michigan, a job characterized by an apparently difficult relationship with his superiors. In 1872 he left Michigan to be chancellor of Syracuse University, lasting only two years. Next he was a professor of geology and zoology at Vanderbilt University, a position he was forced to resign from in 1878 due to his unbiblical views of evolution. Winchell then returned to the University of Michigan, again as a professor of geology and paleontology. There is where he died.

Winchell’s views on evolution were complicated by his religiosity, and his religious life was made difficult by evolution. He developed a kind of transcendental Darwinism in which selection was reduced to inflexible laws from the Creator, a view we would today call Intelligent Design. He then confused it all by writing a popular book called Preadamites, published in 1880. The darker races, he said, lived in Europe and Asia before Adam. Adam and the subsequent “Noachites” were derived from Negroes, according to Winchell, advancing steadily in intellectual development and whiteness while the black race and other Preadamites were left behind. This work is profoundly racist and pseudoscientific, despite the Darwinian gloss he attempted to paint over it.

a-screen-shot-2016-10-10-at-8-49-42-pmb-screen-shot-2016-10-10-at-8-57-04-pmFrontispiece of Winchell (1880).


Bork, K.B. and Malcuit, R.J. 1979. Paleoenvironments of the Cuyahoga and Logan Formations (Mississippian) of central Ohio. Geological Society of America Bulletin 90: 89–113.

Vörös, A., Kocsis, Á.T. and Pálfy, J. 2016. Demise of the last two spire-bearing brachiopod orders (Spiriferinida and Athyridida) at the Toarcian (Early Jurassic) extinction event. Palaeogeography, Palaeoclimatology, Palaeoecology 457: 233-241.

Winchell, A. 1863. Descriptions of FOSSILS from the Yellow Sandstones lying beneath the “Burlington Limestone,” at Burlington, Iowa. Academy of Natural Sciences of Philadelphia, Proceedings, Ser. 2, vol. 7: 2-25.

Winchell, A. 1880. Preadamites; or a demonstration of the existence of men before Adam. Chicago, S.C. Griggs and Company; 500 p.

Wooster’s Fossils of the Week: Upper Ordovician strophomenid brachiopods from Iowa

October 7th, 2016

leptaena-585Since we are covering brachiopods in my paleontology course this week, I’ve chosen a very recognizable genus from the Upper Ordovician of Iowa for our Fossil of the Week. This wrinkly strophomenid brachiopod is of the genus Leptaena Dalman, 1828. It is one of the most common brachiopods in the Lower Paleozoic, ranging from the Ordovician into the Carboniferous. The two specimens above are showing their dorsal valve exteriors.

leptaena-dorsal-585The same specimens are here turned over, showing the ventral valve exterior on the left and the dorsal valve interior on the right.

I always learn something when writing these brief fossil posts. These specimens are labeled in our collections as Leptaena rhomboidalis (Wahlenberg, 1818), the most common species name I’ve seen for this genus. Hoel (2005, p. 266), however, says: “In fact, L. rhomboidalis is known only from Gotland, [Sweden,] where it was confined to moderate energy reef environments during the early Wenlockian [Silurian].” So this species is only Silurian, and only found on a Swedish island. I’ll just leave it in open nomenclature, then, as Leptaena sp. The taxonomic details of the many species in the genus are beyond my skills and experience.
gwahlenbergThe erroneous species name, though, does introduce us to a fascinating Swedish naturalist named Göran Wahlenberg (1780-1851). This man is best known as a botanist, but he also had many geological and paleontological interests. He entered Uppsala University in 1792, earning a doctorate in medicine in 1806, and then joining the faculty to teach botany and medicine (with much more emphasis on the first). He occupied the university chair previously held by the demigod taxonomist Carl Linnaeus. He was elected at a young age to the Royal Swedish Academy in 1808. Wahlenberg’s primary work was with plant biogeography, especially in Sweden, but he made many scientific forays throughout Scandinavia and into Central Europe. He named Anomites rhomboidalis in 1818, which was later added to the genus Leptaena.

Wahlenberg studied glaciers in Scandinavia, making many observations about glacial striations and moraines we would recognize today. His main overarching theory of Earth history was that massive vulcanism in the “pre-Adamite” past caused great climate changes, eventually producing a global flood, the evidence for which included glacial erratics strewn throughout northern Europe. He was one of the first naturalists to posit connections between atmospheric composition and global temperatures.

What the scientific biographies of Göran Wahlenberg don’t often mention is that he is credited as the first person to bring the pseudoscience of homeopathy to Sweden. He studied the medicinal ideas of the founder of homeopathy, Samuel Hahnemann, and declared they had merit. He was an enthusiastic advocate, making him one of the “pioneers of homeopathy”. In his defense, at that time homeopathy was no doubt safer than mainline medicine!


Hoel, O.A. 2005. Silurian Leptaeninae (Brachiopoda) from Gotland, Sweden. Paläontologische Zeitschrift 79: 263-284.

Kelly, F.B. 1967. Silurian leptaenids (Brachiopoda). Palaeontology 10: 590-602.

Wahlenberg, G., 1818. Geologisk avhandling om svenska jordens bildning. Uppsala.

Last Day of GSA 2016: An empty room awaits

September 28th, 2016

podium-view-092816DENVER, COLORADO — The last day of the Geological Society of America meeting has finally arrived. Early this morning the above room will begin to gather a few of the remaining participants for a series of talks, including my own. As always I am very much looking forward to it being over, which will happen precisely at 10:15 a.m. I will then rush out of the room, the Convention Center and my hotel to start the journey home.

slide01-092816I’ll share my first and last PowerPoint slides. This is an exciting project Paul Taylor and I have started. Today we may learn if it has legs or will be immediately crippled by a few cogent observations.

slide36-092816This isn’t the last of the Wooster Geology presentations. There is one more poster this afternoon that will be reported in the next post. As for me, my meeting is nearly over. Safe travels to everyone!

Wooster’s Fossils of the Week: Ordovician cryptostome bryozoans from southern Ohio

September 23rd, 2016

waynesville-cryptostomesA short entry this week because the annual meetings of the Geological Society of America and Paleontological Society begin this weekend in Denver. (Wooster is sending 17 students this year. Seventeen! A record for us.)

The above image is a detail from a slab of limestone collected from the Waynesville Formation (Upper Ordovician, Katian) on a class field trip earlier this month to Caesar Creek, Warren County, Ohio.  The stick-like fossils are mostly cryptostome bryozoans generally aligned by the last of some ancient water current. Cryptostomes are small and fussy  bryozoans, and thus hard to work with. There hasn’t been a significant overview of Ohio Ordovician cryptostomes for quite awhile, so I suspect there is much new to learn about them.

The following posts will be from Denver!

Wooster’s Fossils of the Week: New Early Silurian crinoids from Estonia

September 16th, 2016

1 Hilliste crinoidsIt has been a good year for new fossil taxa on this blog. I’m pleased to present a fauna of Early Silurian crinoids from the Hilliste Formation (Rhuddanian) exposed on Hiiumaa Island, western Estonia. They are described in a paper that has just appeared in the Journal of Paleontology (early view) written by that master of Silurian crinoids, Bill Ausich of Ohio State University, and me, his apprentice.

Here’s the simplified caption for the above composite image: Rhuddanian crinoids from western Estonia: (1) Bedding surface comprised primarily of crinoid columnals and pluricolumnals; (2) Radial circlet of an unrecognizable calceocrinid; (3) Basal circlet of an unrecognizable calceocrinid; (4) Holdfast A: Virgate radices anchored in coarse skeletal debris; (5) Holdfast D: Simple discoidal holdfast cemented to a bryozoan; (6, 7, 8) Hiiumaacrinus vinni n. gen. and n. sp.: 6, D-ray lateral view of calyx, 7, E-ray lateral view of calyx, 8, basal view of calyx; (9) Holdfast B: Dendritic holdfast in coarse skeletal debris; (10) Eomyelodactylus sp. columnal; (11) Holdfast C: Simple discoidal holdfast cemented to a tabulate coral; (12) Two examples of Holdfast E: Stoloniferous holdfasts cemented to a tabulate coral; (13) Protaxocrinus estoniensis n. sp. lateral view of partial crown, top of radial plate indicated by line.

Here is the abstract: “Rhuddanian crinoid faunas are poorly known globally, making this new fauna from the Hilliste Formation of western Estonian especially significant. The Hilliste fauna is the oldest Silurian fauna known from the Baltica paleocontinent, thus this is the first example of the crinoid recovery fauna after the Late Ordovician mass extinction. Hiiumaacrinus vinni n. gen. n. sp., Protaxocrinus estoniensis n. sp., Eomyelodactylus sp., calceocrinids, and five holdfast types are reported here. Although the fauna has relatively few taxa, it is among the most diverse Rhuddanian faunas known. Similar to other Rhuddanian crinoid faunas elsewhere, the Hilliste crinoid fauna contains crinoids belonging the Dimerocrinitidae, Taxocrinidae, Calceocrinidae, and Myelodactylidae; most elements of the new fauna are quite small, perhaps indicative of the Lilliput Effect.”
3 Hilliste diagramNo crinoid paper is complete without camera lucida drawings (scale bar for all figures is one mm): (1) Hiiumaacrinus vinni n. gen. and n. sp.; (2) Radial circlet of an unrecognizable calceocrinid; (3) Basal circlet of an unrecognizable calceocrinid; (4) Protaxocrinus estoniensis n. sp.
4 Olev062511There are two new species and one new genus here. Hiiumaacrinus vinni is named first after the lovely Estonian island where the species is found, and then after our good friend and colleague Olev Vinn (above) at the University of Tartu. Olev first introduced me to the Ordovician and Silurian of Estonia, and then was an excellent field companion for Bill and me on our Estonian field trips.
2 Hiiumaa mapA reminder where Hiiumaa Island is, and for that matter, the nation of Estonia.

5 HillisteQuarry071312Here is Hilliste Quarry on Hiiumaa Island. Still one of my favorite places to work. Very, very quiet.

6 HillisteAusich071112Here is Bill Ausich in the quarry during our 2012 expedition. The pose is known among paleontologists as “the Walcott“.

7 Holdfasts071112Here is one of the specimens collected by Bill in July of 2012. You may recognize this field scene as figure 12 in the top image of this post. These are two examples of crinoid holdfasts on a tabulate coral.

Please welcome Hiiumaacrinus vinni and Protaxocrinus estoniensis to the paleontological world!


Ausich, W.I. and Wilson, M.A. 2016. Llandovery (Early Silurian) crinoids from Hiiumaa Island, Estonia. Journal of Paleontology (early view).

Ausich, W.I., Wilson, M.A. and Vinn, O. 2012. Crinoids from the Silurian of Western Estonia (Phylum Echinodermata). Acta Palaeontologica Polonica 57: 613‒631.

Ausich, W.I., Wilson, M.A. and Vinn, O. 2015. Wenlock and Pridoli (Silurian) crinoids from Saaremaa, western Estonia (Phylum Echinodermata). Journal of Paleontology 89: 72‒81.

2016 Wooster Paleontologists Field Trip

September 11th, 2016

paleo-class-2016-smallIt was a beautiful day for fieldwork. Every fall I take Wooster’s Invertebrate Paleontology class into the field to collect specimens for study and analysis during the rest of the semester. It’s fun because these students have only completed two weeks of the course and almost everything is new. One steady change over the years has been in the number of paleo students. Gone are the days when we could all pile into a 15-passenger van and spend three days in Kentucky. Now we have to take a bus, and tight student schedules limit us to one day. These constraints mean that going to Caesar Creek Lake in Warren County, Ohio, is the best choice. We’ve been here now several times. here we examine Ordovician fossils in limestones and shales of the Waynesville, Liberty and Whitewater Formations (all of which equal the Bull Fork Formation).

collecting-091116The weather was ideal, but the night before saw heavy rains. Bit of a mud fest today.

brach-slab-091116The fossils, of course, are world-class in the Cincinnati area. Here’s a wonderful slab of strophomenid brachiopods with Josh Charlton’s hand for scale. At least the rains washed the rocks clean!

lab-sink-091116Next stop for the students: washing their specimens in the lab sink at Wooster. Anyone who has worked in the Cincinnatian knows that the clay can be particularly tenacious. Students learn paleo from the very basics!


Wooster’s Fossils of the Week: Tiny athyridide brachiopods from the Lower Carboniferous of the West Midlands of England

September 9th, 2016

1 Hustedia radialis 585These little brachiopods were also in the recent gift package from Clive Champion, our English brachiopod expert and friend. They tested my photographic skills, being too large for our photomicroscope and at the limit of resolution for my camera with its extension tubes. They are the athyridide Hustedia radialis (Phillips, 1836) from the Chadian-Arundian Limestone (Viséan, Lower Carboniferous) exposed near Wetton, Staffordshire, England. Brachiopods of this size are often referred to as “micromorph“, with some debate as to whether they are dwarfed adults or juveniles. With this fauna the consensus is the former.

Athyridide brachiopods are “spire-bearing”, meaning they have complexly-spiraled lophophore supports (brachidia) inside their shells. The lophophore is a tentacular device that creates a water current and traps organic bits from it for nutrition. These tiny critters thus had surprisingly elaborate feeding systems. The first paleontologist to grind through these minuscule shells to sort out the twists and turns of their microscopic brachidia is a hero of science.
2 John Phillips (1800-1874)Hustedia radialis was named in 1836 by one of the most important English geologists of the 19th Century, John Phillips (1800-1874). He originally called it Terebratula radialis, a common genus name applied at the time to biconvex brachiopods with pedicle openings (the hole for the attaching stalk visible at the pointy end of the shell).
3 Geology of YorkshireHe named it in the second volume of his Geology of Yorkshire series.
4 Brachs PhillipsSee if you can find the two figures of Terebratula radialis in Plate XII of the book. (Hint: small, triangular and ribbed!)

John Phillips was born in Wiltshire in 1800. His mother was a sister of the famous William “Strata” Smith, another founding father of modern geology. Phillips father and mother died when he was only seven years old, so William Smith took over raising him, despite his genteel poverty. Phillips traveled with Smith throughout England in the course of making Smith’s famous 1815 map. Phillips had a spotty formal education, but was clearly a quick study. By 1824 he was organizing museum fossil collections in Yorkshire, and in 1826 he became keeper of the Yorkshire natural history museum. Phillips then advanced very quickly, helping organize the new British Association for the Advancement of Science, becoming a professor of geology at King’s College London, and then at the age of 34 he was elected a Fellow of the Royal Society. All the while he kept up a prodigious rate of publication. The honors and positions continued for Phillips, with him eventually becoming a Reader of Geology at Oxford University. A remarkable career with such an unpromising start.
5 Phillips 1841 160Phillips published the first geological time scale in 1841, inventing the term “Mesozoic” in the process. The above clip is from Phillips (1841, p. 160).
6 Phillips 1860 time scaleHere is his 1860 version of the geological time scale (Phillips, 1860, p. 51).

After an April 1874 dinner at All Souls College in Oxford, John Phillips fell down a flight of stone steps, dying the next day. No doubt but for this fall he would have continued producing geological work into the next decade.


Brunton, C.H.C. 1984. Silicified brachiopods from the Viséan of County Fermanagh, Ireland (III). Rhynchonellids, spiriferids and terebratulids. Bulletin of the British Museum (Natural History), Geology 38: 27–130.

Brunton, C.H.C. and Champion, C. 1974. A Lower Carboniferous brachiopod fauna from the Manifold Valley, Staffordshire. Palaeontology 17: 811–840.

Mottequin, B., Sevastopulo, G. and Simon, E. 2015. Micromorph brachiopods from the late Asbian (Mississippian, Viséan) from northwest Ireland (Gleniff, County Sligo). Bulletin of Geosciences 90: 307-330.

Phillips, J. 1836. Illustrations of the geology of Yorkshire, Part 2. The mountain limestone district. 253 pp. John Murray, London.

Phillips, J. 1841. Figures and Descriptions of the Palaeozoic Fossils of Cornwall, Devon and West Somerset. 231 pp. Longman, Brown, Green and Longmans, London.

Phillips, J. 1860. Life on the earth: its origin and succession. 224 pp. Macmillan and Company, London.

7 Gould bookplateFun feature of that last reference: Google Books scanned a personal copy of Stephen Jay Gould, a famous American paleontologist and evolutionary theorist.

8 Darwin quoteOn one of the front pages is this penciled note: ‘Unreadable, dull’ – Charles Darwin to [unknown] 15/1/61. [UPDATE: See comment from Katherine Marenco below.]

Wooster’s Fossils of the Week: Mystery fossil solution — an oyster from the Middle Jurassic of southern England

August 30th, 2016

Mystery fossils 081916 585Last week I gave my students in Wooster’s Invertebrate Paleontology course a fossil to identify (shown above), using any techniques they want. This was their first task in the course, so it was difficult for most of them. I hope it was a good introduction to practical paleontology and the mysteries of taxonomy. One student, Josh Charlton, nailed it all the way to the species. Several other students got close.

These are Middle Jurassic oysters properly identified as Praeexogyra hebridica (Forbes, 1851). I collected them many years ago from the Frome Clay (Bathonian) at Langton Herring along the coast of Dorset, southern England. They are extremely common fossils there, crunching underfoot as they erode out into the surf. These oysters lived in estuaries, where there was a mix of fresh and marine waters. In 1976, John Hudson and our friend Tim Palmer sorted out the systematics and  evolution of this oyster species, moving it from Ostrea and Liostrea to the genus Praeexogyra.
Forbes diagramThis oyster species was originally described in 1851 as Ostrea hebridica by Edward Forbes (1815-1854) from Jurassic sediments on the Scottish Isle of Skye in the Inner Hebrides (hence the name). As was typical of many nineteenth century fossil descriptions, the illustrations (above) and diagnoses are not particularly helpful. Forbes (1851) wrote, “Being very familiar with the oysters of the Wealden and Purbeck I cannot admit this identification, nor can I refer the Loch Staffin shell to any known fossil, although, as usual in this variable genus, it is difficult to express in words its marked distinctions.” We wouldn’t get away with such a conclusion for a new species today, but to be fair, oysters are notoriously difficult to describe. Forbes knew that this species “inhabited brackish water” in the Jurassic.

Forbes bust to useEdward Forbes FRS, FGS (above) was born on the Isle of Man in 1815, the year of Waterloo. He was, as they said then, a sickly child unable to attend a regular school for long. He traveled to London when he was 16, though, to study art. That didn’t work out, so he became a medical student at the University of Edinburgh. Forbes was intrigued more with natural history than medicine (a common story!), so he dropped his medical plans and set out to become a naturalist skilled in paleontology, mineralogy, zoology, anatomy and botany. His younger brother David became a well-known mineralogist. Edward Forbes caught on quickly. In 1838 he published a summary of the mollusks found on the Isle of Man. He was 23 years old. Forbes traveled widely, accumulating more observations, experiences and colleagues. He had many publications and advocated numerous hypotheses about the distribution of life forms. Some had lasting value (like the distribution of flora before and after glaciation intervals) and others were a bit naive (such as his idea that there is no marine life below 300 fathoms). He was a president of the Geological Society of London (1853), and in 1854 became the Professor of Natural History at Edinburgh, his driving ambition. Unfortunately his health problems caught up with him and he died that year at age 39.

Edward Forbes played a critical role in the history of science by being a mentor of Thomas Henry Huxley. Forbes advised Huxley as a young man and helped him publish his earliest works. Forbes introduced Huxley to his circle of colleagues, which eventually led to the latter’s election to the Royal Society while only 26 years old. Huxley wrote a touching obituary for his young friend Edward Forbes.


Anderson, F.W. and Cox, L.R. 1948. The “Loch Staffin Beds” of Skye; with notes on the molluscan fauna of the Great Estuarine Series. Proceedings of the Royal Physical Society of Edinburgh 23: 103-122.

Anderson, T.R. and Rice, T. 2006. Deserts on the sea floor: Edward Forbes and his azoic hypothesis for a lifeless deep ocean. Endeavour 30: 131-137.

Forbes, E. 1851. On the Estuary Beds and the Oxford Clay at Loch Staffin, in Skye. Quarterly Journal of the Geological Society 7(1-2): 104-113; plate 5, figs. 4a-4c.

Hudson, J.D. and Palmer, T.J. 1976. A euryhaline oyster from the Middle Jurassic and the origin of the true oysters. Palaeontology 19: 79-93.

Wooster’s Fossils of the Week: A puzzle for my paleo students!

August 26th, 2016

Mystery fossils 081916 585Every year I start my Invertebrate Paleontology course by giving every student an “unknown” fossil to identify. (Here is last year’s version.) This is not always easy since each student gets the same species from the same horizon and with the same preservation. As classes get larger (I have 27 students this semester) I have to dig deeper into my collections. I found some good ones today that have enough variation to challenge them.

These students are just beginning the journey, of course, so they usually know little about fossils. This exercise gets them into the online fossil literature immediately, and provokes early questions about the information used in taxonomy and the dilemmas of systematics based on morphology alone. Their task:

  1. Identify the fossil by scientific name as narrowly as possible. Phylum is a start, then Class, Order and so on down to the grand prize of correctly determining the species.
  2. Estimate the age of the fossil. Finding the period during which it lived is good; the actual stage it was found in, better.
  3. Make an educated guess at where this fossil was found. Chances are if you are right about the name and age, and then consider the places my students and I do fieldwork, you’ll come up with at least a region.

Next week I will post here the identity and collecting location of these fossils, along with the name of the student who came the closest to the right answers. You, Dear Reader, can make a guess in the comments!

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