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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.

Wooster’s Pseudofossil of the Week: It’s not what it looks like

September 30th, 2016

Pseudocoprolite 585Impressive, isn’t it? You can practically smell it steaming on your screen. Hard to believe this object is Miocene in age, about 6 million years old.
Pseudocoprolite top view 585Here’s another similar specimen in a top view, if we can say that.
Pseudocoprolite side view 585And here’s a side view. Notice the rich color, long, parallel striations, and “pinched” ends. If these aren’t fossil feces, officially known as coprolites, they’re excellent imitations. They’ve been prime attractions in our first paleontology lab.

These evocative objects are primarily made of siderite, making them dark and heavy. Our specimens above come from the Wilkes Formation (upper Miocene) in southwestern Washington state. They are enormously abundant and thus common in rock shops and museums around the world. In that is your first clue: how can feces with such exquisite detail be preserved so perfectly in such enormous numbers in so few places? My answer, along with many other geologists, is that these are pseudocoprolites made by inorganic means. Their extrusive nature and appropriate color gives us the illusion of poop.

I’m highlighting these objects this week because a paper appeared last month in the journal Lethaia making a case that they actually are biological in origin. Broughton (2016), in a long bit of prose and analysis, concludes that the Wilkes Formation objects are a mix of giant earthworm “mineralized intestinal remains (Type 2)” and coprolites “from unknown vertebrates” (Type 1). I don’t buy Broughton’s interpretations, but found them fascinating enough to make his paper part of a reading exercise in my paleontology class this month. The most relevant references are below so you can do your own reading and decide what these curious extrusions (or intestinal casts) are.

Let’s start with this excellent 2014 article by Brian Switek for National Geographic: “Was Six-Million-Year-Old Turd Auctioned for $10,000 a Faux Poo?” Yes, one of these curiosities actually sold for $10,370 at an auction … and it is over 100 centimeters long! (Check out the images in this NPR article on the auction. That would be an epic poop for anyone.) This auctioned specimen is an example of what Broughton (2016) calls Type 2; he believes they are essentially mineralized guts of really large burrowing earthworms. He makes his case by interpreting the striations as muscle fiber impressions, and the shapes as resulting from peristaltic motions inside the worms. (Seilacher et al., 2001, had similar ideas.) The smaller “faecal-like specimens”, like we have at Wooster, are his “Type 1”. As far as I can tell, only length separates Type 1 from Type 2 in Broughton’s classification and, as might be expected, “Some fragmentary Type 2 specimens may be misidentified as Type 1.” It is odd that Types 1 and 2 are identical in every feature but size, yet are given very different origin stories.

Critical observations to keep in mind as you explore this mystery: (1) These siderite objects have no inclusions of organic material — not a seed, woody bit, or bone fragment; (2) There are no associated vertebrate skeletal remains or other traces, and no evidence for earthworms either; (3) They are incredibly abundant in limited horizons, and unknown elsewhere; (4) They range in size from a centimeter or less to over 100 centimeters long; (5) You’d think you’d find a few squashed, now and then, or burrowed by insects, but they are in spectacular three-dimensional preservation.

I support the earlier interpretations of these excrement-appearing rocks as deformations of soft, plastic sediments by inorganic processes, as thoroughly developed by Spencer (1993), Mustoe (2001) and Yancey et al. (2013). They may have been extruded through rotting hollow logs by compaction, liquified by seismic activity, or squirted through cracks by natural gas emissions (which would be ironic!). That these pseudocoprolites were squeezed through something seems obvious; it is unlikely they came to us by way of animals.


Broughton, P.L. 2016. Enigmatic origin of massive Late Cretaceous‐to‐Neogene coprolite‐like deposits in North America: a novel palaeobiological alternative to inorganic morphogenesis. Lethaia (early view)

Mustoe, G.E. 2001. Enigmatic origin of ferruginous “coprolites”: Evidence from the Miocene Wilkes Formation, southwestern Washington. Geological Society of America Bulletin 113: 673-681.

Seilacher, A., Marshall, A., Skinner, C. and Tsuihiji, T. 2001. A fresh look at sideritic ‘coprolites’. Paleobiology 27: 7–13.

Spencer, P.K. 1993. The ‘coprolites’ that aren’t: the straight poop on specimens from the Miocene of southwestern Washington State. Ichnos 2: 231–236.

Yancey, T.E., Mustoe, G.E., Leopold, E.B. and Heizler, M.T. 2013. Mudflow disturbances in latest Miocene forests in Lewis County, Washington. Palaios 28: 343–358.

Last Wooster Geologist Presentation at #GSA2016

September 28th, 2016

Denver, CO – The honor of the last presentation at #GSA2016 goes to Amineh AlBashaireh (’18), who has a poster on her summer work at Black Mountain in San Diego, CA.

Amineh AlBashaireh ('18) has been conducting research on the occurrence and mobilization of arsenic.

Amineh AlBashaireh (’18) has been conducting research on the occurrence and mobilization of arsenic.

Congratulations, Wooster Geologists, on another successful GSA meeting!


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!

Day Three of Wooster Geology at GSA 2016: Structure, lakes and John Muir

September 27th, 2016

jimerson-092716DENVER, COLORADO — Cole Jimerson started us off in the poster session today at the annual meeting of the Geological Society of America.

jimerson-grilledHe faced a tough grilling at the start from none other than our own Dr. Pollock. Notice that a beer bottle has now appeared on the table!

siegel-092716Helen Siegel and her poster on structural geology in Utah (co-authored with Dr. Shelley Judge). This was a rare moment that Helen didn’t have company.

wayrynen-092716Andrew Wayrynen rounded out Team Wooster this afternoon with his poster on John Muir and Glacier Bay. Andrew is a double major in Geology and English.

Another beautiful and productive day in Denver, although we are all starting to drag a bit!

Wooster Geology Alumni at GSA 2016

September 26th, 2016

gsa-wooster-2016-585DENVER, COLORADO — Many of the Wooster Geology alumni at GSA, along with current students and professors Pollock and Wilson, gathered this evening for conversations. It was great fun with many stories and lots of good advice for our students.

dr-sophie-lehman-092616We celebrated Sophie Lehman’s (’08) brand new PhD. Congratulations, Dr. Lehman! We remember your first GSA presentation.

steph-and-amineh-092616Here is Wooster alumna Steph Jarvis talking to current student Amineh AlBashaireh. Many connections made tonight.

More later on the day of talks and posters.

Another day of Wooster Geology at GSA 2016: Volcanoes and Fossils

September 26th, 2016

jester-092616DENVER, COLORADO — On this second day of the Geological Society of America meeting we had several Wooster presenters. Above Cassidy Jester (’17) describes her developing Senior Independent Study work on Jurassic “snuff-boxes“.

wallace-and-kumpf-092616Dr. Pollock’s students Chloe Wallace and Ben Kumpf talked about their work on the geochemistry of a volcanic system in Iceland.wilson-092616

And there was me! This is my poster (With Caroline Buttler of the National Museum of Wales) on an Ordovician cave fauna.

taylor-092616Honorary Wooster Geologist Paul Taylor of the Natural History Museum in London also presented in our session. His project is the interpretation of a magnificent set of Carboniferous bryozoans.

poster-session-092616Finally, here is what a typical GSA poster session looks like. You can imagine the accompanying loud buzz of several thousand voices.

Association for Women Geoscientists Breakfast at #GSA2016

September 26th, 2016

Denver, CO – The Association for Women Geoscientists (AWG) held their annual breakfast at #GSA2016, where they recognized those people who make exceptional contributions to their mission. AWG seeks to encourage the participation of women in the geosciences, exchange information (technical, educational, professional), and enhance professional growth and advancement. After this morning’s inspirational stories, who wouldn’t want to become a member? One notable part of the program was the recognition of women geoscientists from the Mongolian Chapter of AWG.

Representatives from the Mongolian Chapter of AWG were recognized for their efforts to support women geoscientists. They began as an informal club in 2012 and were officially recognized as an international chapter of AWG in 2014.

Representatives from the Mongolian Chapter of AWG were recognized for their efforts to support women geoscientists. They began as an informal club in 2012 and were officially recognized as an international chapter of AWG in 2014.


This year’s Outstanding Educator Award winner was Barbara Dutrow, a renowned mineralogist.

Barbara Dutrow accepts the Outstanding Educator Award. One of her nominators was a former student who was profoundly affected by her undergraduate research experience with Barbara.

Barbara Dutrow accepts the Outstanding Educator Award. One of her nominators was a former student who was profoundly affected by her undergraduate research experience with Barbara.


 Me and my research students, Rachel Heineman ('17, Oberlin) and Amineh AlBashaireh ('18), at the AWG breakfast. My students had the opportunity to network with lots of influential mentors, including a CUR Councilor, GSA Fellow, potential graduate advisors, and the Outstanding Educator Award Winner.

Me and my research students, Rachel Heineman (’17, Oberlin) and Amineh AlBashaireh (’18), at the AWG breakfast. My students had the opportunity to network with lots of influential mentors, including a CUR Councilor, GSA Fellow, potential graduate advisors, and the Outstanding Educator Award Winner.


Wooster geologists begin their 2016 Geological Society of America meeting adventure

September 25th, 2016

bell-092516DENVER, COLORADO — Seventeen Wooster students have now arrived in Denver for the annual meeting of the Geological Society of America. Eleven of them are giving presentations of some sort. We are very proud of each. Dr. Meagen Pollock and I may not be able to get to each poster, so we’re going to post what we can when we can. Today was big for Wooster’s Dendrochronology (Tree-Ring) Lab under the direction of Dr. Greg Wiles. All the work today was from various Alaska expeditions.

Early this morning I found Brandon Bell (’18, above) with his poster. Brandon is a double-major in history and geology. His project here on the Bering Expedition is quite fitting.

deck-585-092516Clara Deck (’17) here presents her dendroclimatic project.

deck-at-work-585-092516Clara at work doing the poster thing.

gunderson-092516Jeff Gunderson (’17) is also representing Wooster’s dendrochronology lab with his fine poster.

hilton-585-092516Annette Hilton (’17) is presenting for the dendrochronology lab.

mcgrath-585-092516As is Sarah McGrath (’17).

I’m very impressed with our students and their cheerful, confident and creative presentations. It is a daunting task giving a poster at a national meeting, and they are doing it exceptionally well.

More student presentations later! We’re having a good and productive time in Denver.


Wooster Geology Alumnae in the Bearded Lady Project

September 24th, 2016

bearded-lady-signWooster has produced many paleontologists over the last century. I’m not sure exactly why we’ve had such an abundance of people who chose to devote their lives to the study ancient life, but I am most grateful to the tradition. Women have been prominent among the Wooster paleontology cadre. There is currently a developing project celebrating the accomplishments of women working in paleontology and “challenging the face of science”. It is called The Bearded Lady Project. Two of our alumnae are featured in a photographic exhibit about the project at the Geological Society of America meeting in Denver this week.

kelley-blpThis is Tricia Kelley, recently retired as a distinguished professor of geology at the University of North Carolina, Wilmington. She is also a past president of the Paleontological Society. I would not have recognized her in this bearded state without a caption on the photo! (Sorry I can’t avoid reflections in the glass.)

clites-blpErica Clites was one of my students. She is presently a Museum Scientist at the University of California Museum of Paleontology in Berkeley. I do recognize her!

We have other accomplished women paleontologists from Wooster — and other geologists. Tricia and Erica represent them well. We are very proud!

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