The delightful Fall 2022 Paleoecology class at Wooster

I was so impressed with the post by Professor Greg Wiles about his Fall 2022 Geomorphology class that I decided to highlight the Fall 2022 Paleoecology class as well. It was a great group of students, and we did an extraordinary amount of scholarly work: 26 quizzes, two tests, one final exam, two essays, a research paper, a research presentation, an extensive field project, and three other lab reports. They flourished and in turn through their research taught me quite a bit about many paleoecology topics. We were assisted throughout by our brilliant, patient, tireless, cheerful Teaching Assistant Brianna Lyman.

Early in the course we had a day-long field trip to southeastern Indiana (locality C/W-148 near Richmond) described in an earlier post. The goal was for each student to make a large collection of fossils from the upper Whitewater Formation (Upper Ordovician) that would be the raw material for a detailed paleoecological report due at the end of the semester. Nick Wiesenberg, our geological technician, was invaluable in the planning and successful completion of this little expedition.

These are the filled sample bags from the field trip, one for each student.

The next step was to wash the specimens for further analysis.

One of the student trays with typical specimens from the trip, including brachiopods, bryozoans, bivalves, gastropods, corals, cephalopods, monoplacophorans, and a few rare trilobites. There were also trace fossils, including numerous borings in the calcitic shells.

This is a completed tray at the end of the semester. Specimens are cleaned, labeled, and identified. Each student made at least two acetate peels, one from a rugose coral and the other from a bryozoan. Each student then wrote a report on the taxonomy, taphonomy, and paleoecology of their collection, supplementing their observations with the discoveries and ideas of their classmates. It was a nice mix of individual research and group discussions.

Another lab exercise detailed the ontogeny of the rugose coral Grewingkia canadensis from the same field site. We clearly have enough specimens for each student to measure the dimensions of numerous corals. They then used a statistical package (Past4) to make various graphs for interpretations.

We also had a foraminiferan “picking” exercise. Each student had a vial of sediment from a drill hole in the Gulf of Mexico (Frio Formation, Oligocene). They then collected foraminiferan tests with a thin wet brush and placed them on slide covered with water-soluble glue.

The process required careful hand-eye coordination to not lose the little critters in the transfer from sediment to tray!

This image shows a sediment vial, a picking brush, and a completed slide. Each number on the slide has a tiny specimen glued by it. The students then identified the foraminiferans and assessed the likely depth that the benthic forms lived.

The final exercise involved identifying shark teeth from the Cretaceous Menuha Formation of southern Israel. We have a large collection of these teeth from the Independent Study thesis of Andrew Retzler (’11). We used Retzler et al. (2013) as our guide for identification of these sharks and their paleoecological context.

I had an excellent time in this course with these creative, hard-working, resilient, happy students.

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Local Geomorphology and What We Learned

This is a post outlining some of the work we did in Wooster’s class in Geomorphology. One of the early labs was Browns Lake Bog and the Soil Catena.

The landforms in the area are spectacular – here is a kame, a photo taken  as we ventured down into the bog.

The group shares a light moment before the 20+ species of mosquitos descended on them in the forest.

The soils from the top of the kame to the base varied more than the group predicted.

We also sampled soils just east of the campus golf course.

Nick and Jerry in the soil pit measuring magnetic susceptibility as Des records the data.

The C-horizon on the left is a sandy, silt gravel – the B-horizon in the middle is blocky loam and the A is a more brown silty material.

The team coring an old growth (300+ year) tree growing on top of the soil site. The landform is a kame terrace that has likely been weathering in place for the last 14,000 years with additional windblown silt being added (or removed) from time to time during the Holocene.

At Zollinger’s Sand and Gravel – posing at the base of the section which is Mississippian bedrock. A big thank you to the Zollinger family for allowing us to work here and for showing us around.

This side of the pit is still being mined, whereas other portions serve as land fill. We learned that lodgement till can be fractured and that it also can be mined and serve as a landfill liner.

On the way back to campus we stopped at the artesian spring near the Wayne County Airport.

Of course not class would be complete without a trip to Spangler. Here the group is standing inf ront of one of the unconformities, which is composed of a lodgement till overlain by fluvial and alluvial sediments.  The interface of these units is where the geochmistry is just right to generate concretions.

The increasingly greater precipitation events are moving larger and large block of bedrock. Here the Wooster Shale is being excavated by 1-2 inch storm events. Our hypothesis is that erosion rates over the last few decades are unprecedented perhaps over much of the Holocene.
Big blocks are moved routinely – they are plucked out by the stream along planes of weakness (fractures). Note how the shales break up readily. A block like those above will be mud again in a matter of months. Swelling clays and strong wetting and drying does the job.

Here is a series of debris flows (gray sediment) – we obtained two radiocarbon ages that show intervals of mass movements about 2.5 ka, these are dates on charcoal that may be from fires used in land management by native Americans at the time.

Stream gaging along Apple Creek. The group gets some hand-on experience with the equipment and puzzles over the various facies of a fining upward fluvial sequence.

Nick and Tyrell take turns in the deep end.

Jack giving the group the rundown on riparian vegetation.

As it turn out the floods here get pretty high, this tree was scarred when a log (or a washing machine) floated by during a high flow.


The class at Fern Valley standing in front of Columbia Gas’ well-head for the natural gas storage field. The group was investigating the possibility that mass movements at the site might impact the infrastructure and pipelines in the area.

The slump block at Fern Valley is clearly seen from above. It is a series of glacial ice-contact stratified drift deposits overlain by a thick (40+ foot) layer of varved lacustrine clays. What you see in the woods is a major 2-3 meter scarp (normal fault) as the block descends into the valley.

The class at Fern Valley. A big thank you Nick Wiesenberg for arranging the logistic for the trips. We would also like to thank bus drivers Mark Livengood and Fred Potter for getting us to and from the sites safely. A special thanks to Fred who will be retiring soon – we appreciate your expertise and knowledge of the Wooster area.

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Paleoecology field trip to the Upper Ordovician of eastern Indiana: Haven’t done this for awhile!

Richmond, Indiana — Today Nick Wiesenberg (our invaluable geological technician), Brianna Lyman (my excellent Teaching Assistant), and I took the 15 students in the Paleoecology course to the fossiliferous Upper Ordovician of eastern Indiana (upper Whitewater Formation). It’s a location (C/W-148) that I’ve taken students to many times, but not since 2019 because of … you guessed it … pandemic. We had a wonderful time collecting bags of specimens for exercises and reports this semester. It was a wonderful day, even if it was seven hours of driving for one hour of fieldwork!

This is a typical view of the fossils available here in abundance. Note the bryoimmurations!

Bags of fossil treasure waiting to be opened in lab. First step will be washing and sorting. This is going to take awhile!

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Who knew that crinoids could be boring? A possible bioeroding crinoid attachment structure from the early Silurian of Estonia (new paper)

Our hard-working and observant Estonian colleagues (Olev Vinn and Ursula Toom) recently made a remarkable discovery among Estonian early Silurian fossils: an attachment structure of a stalked crinoid that apparently bioeroded its way into a calcitic stromatoporoid skeleton.

There’s a lot packed into that opening sentence. (And you’ve noticed that “remarkable” is a relative term depending on your interests!) For orientation, a crinoid is an arm-bearing, filter-feeding marine echinoderm with a very long evolutionary history to the present day. They have skeletons of calcite typically consisting of a flower-like crown with feeding appendages, a stem (or stalk) made of stacked disks, and some sort of holdfast structure. That holdfast can be quite variable, from roots in muddy sediments to thick disks cemented to hard substrates.

Generalized diagram of a crinoid drawn by our coauthor Bill Ausich.

Bioerosion is the biological erosion of a hard substrate by either mechanical means (grinding, rasping, scraping, biting, drilling) or chemical (such as acidic dissolution) producing structures like borings, grooves, drillholes, etc. Until this work, no crinoids living or extinct have been known to bioerode their substrates. Here, though, as you can see in the top image, we appear to have a crinoid that has done just that way back in the Silurian.

The top image is of a thin-section cut through a crinoid holdfast attached to a stromatoporoid, which is a kind of calcareous sponge with a dense, layered skeleton of calcite. The whitish vertical portion is the crinoid stem partially buried in sediment. The yellow arrows show the radices (essentially “roots”) of the crinoid penetrating into the stromatoporoid skeleton, cutting through its topmost layers. It is clear that the crinoid was not simply embedded in the skeleton by stromatoporoid growth — the radices cut through the layers. This crinoid bored into the stromatoporoid (probably chemically) and held on tenaciously. Remarkable. The first indication that a crinoid could do this sort of thing.

Thus far it is only one specimen, so there is the inevitable question mark in the title of this paper. We put it out there as a first report hoping that other such cases may be found. Or, of course, someone could show that our interpretation is not correct.

I love these paleoecological stories! Thank you again to our Estonian friends and colleagues Olev Vinn and Ursula Toom. Bill Ausich and I treasure our friendship and collaboration with them.

For the record, this is the location of the boring crinoid find (from the paper).

And this is the stratigraphy (from the paper).


Vinn, O., Ausich, W.I., Wilson, M.A. and Toom, U. 2022. Did stalked echinoderms bioerode calcareous substrates? A possible boring crinoid attachment structure in a stromatoporoid from the early Silurian (Telychian) of Estonia. Paläontologische Zeitschrift (

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Ten Days in Glacier Bay National Park and Preserve

After spending a day in Juneau gearing up, we flew over to Gustavus, Alaska and then got a ride to Bartlett Cove in Glacier Bay National Park and Preserve. We then rented kayaks and headed into Glacier Bay.

Shortly after being dropped off by the Day Boat at Mount Wright, the team (left to right, Jacob Hassan, Nick Wiesenberg, Jack Whitehouse and Greg Wiles) packed two kayaks and headed for the East Arm (Muir Inlet) of Glacier Bay. The primary objective of this trip is to recover wood that will allow the team to bridge a gap in a 2,000 year long tree-ring record. The age of the wood needs to be about 2000 years old. We know from previous studies where we need to go to optimize our chances of finding that age wood.

Jack and Nick enthusiastic to get paddling north into Muir Inlet (aka the East Arm).

Much of the work was done by examining stream cuts through various glacial and fluvial landforms and working our way up and down outwash fans and streams in the area.

Jacob standing on the bank of a part meandering – part braided stream. He is preparing to crash the brush on the right to make headway.

Jack along the shore of Adams Inlet is optimistic that this section of a fan and delta may contain wood needed for his thesis.

Nick directing the sample collection of a large sitka spruce – likely run over by ice about 1500 years ago during a cold time now known as the LALIA (Late Archaic Little Ice Age). It may be that this cool interval was forced, in part, by major volcanic eruptions and various associate feedbacks in the mid 500s CE.

The group taking a well-deserved rest after a morning of exploring a fan.

One of key deposits that the team investigated were extensive Gilbert type deltas that overlie flooding surfaces from lakes. The lakes (in this case Adams Lake) were formed about 1500 years ago when glaciers in the West Arm advanced damming up the East Arm of Glacier Bay. These lakes preserved forests of that age, and now with ice retreat, isostatic uplift, and erosion the lake are gone and the glaciolacustrine sediment sequences are being eroded away liberating the logs.

This is the same photo – a closeup showing the gray lacustrine clays and silts that are varved (to the right of Jack) and the dipping sands of the foresets overlying the lake clays. Beneath the clays is the flooding horizon that preserved the wood.

Descending a delta from above – here Jacob is walking down the delta foresets into the paleobasin.

The sampling team – yes we have a permit with the National Park Service for chainsaw use. Nick is a chainsaw expert and is able to minimize the saws impact and take high quality samples.

One of the more demanding legs of the trip was thrashing our way up the Casement Glacier outwash plain. We started from its delta in Adams Inlet and headed north with the hopes of setting a camp 8 or so miles from the sea to sample wood at the glacier and on its outwash. Unfortunately, the massive outwash river was pegged along the west side of the valley making travel through the brush difficult. We spent one day sampling washed out logs in the hopes that the complex glacial and fluvial history of the valley might preserve the logs in the age range that we sought. It was slightly miserable with poor weather as well.

Jacob managed to look optimistic as he takes an increment core from a log on the Casement Fan.

Near the delta of Casement River the tidal effects are evident. Here the ebbing tide with a fluvial, unidirectional rippled surface reworks the intertidal mudcracks. Note too, the bubbles evident along the hexagonal boundaries of the mudcracks.

We give a big shout out to Glacier Bay Sea Kayaks for their help with logistics and equipment. These well-maintained boats are necessary for this work as most of the waters we worked in were non-motorized water,  meaning no motor boats.

Here is a shot of the two double kayaks at our Nunatak Fan camp in Muir Inlet. Nick anticipated all the gear and food we would need for the trip and carefully did the planning to ensure that we could fit all we needed in these two boats for the entire 10 days. He also made sure that it would stay dry in the often very wet conditions in this coastal rainforest setting.

The group plans a launch out of one camp on the way to the next. Note the head nets on all the crew. Bugs were an issue and head nets were worn frequently.

A view looking west from he Nunatak camp toward Muir Inlet.

Jack scoped out this barnacle encrusted log – the core was excellent and may be part of the gap-filling ring – width series.

Camped at Muir Point in Muir Inlet. The glacier was here at this fan in 1880 when John Muir has his cabin close to our camp. Only the stone chimney is left to the cabin now and it is well hidden in a nearby forest. Here the group enjoys a nice evening in the intertidal burning driftwood from the beach.

At Muir Point, Nick picked a pile of strawberries that were just right in terms of ripeness and sweetness.

For lunch we had wraps of strawberries, honey peanut butter and nuts. Nick outdid himself with the meal planning.

This is a Bear Highway on top of a storm berm. Each time a bear passes over the berm it steps in the same spots keeping the moss from growing in the footprints.

Nick finding a creative way of crossing the stream in search of the wood.

At the end of the 10 days we were picked up by the day boat and completed our time in Glacier Bay with a trip up the West Arm. The day was brilliant and sunny and we met guides from Alaska Mountain Guides and shared stories of adventures in Alaska.

A sea star revealed itself as we waited at low-tide for the Day Boat.

The group onboard the Day Boat headed back to Gustavus via the West Arm.

Flying back to Juneau a view of the Chilkat Mountains.

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Wooster’s Fossils of the Week: Lingulid brachiopod trace fossils from the Middle Jurassic Carmel Formation of southwestern Utah

This is a short trace fossil story with two disappointments, one much more than the other. It involves trace fossils made by lingulid brachiopods, a marine invertebrate group with a very long geological history. The earliest appeared in the Cambrian, and, as you can see from the top image, they are very much alive today. (Image of Lingula anatina from Wikipedia.)

Lingulid brachiopods have two chitino-phosphatic valves (shown at the left end in the image above) and a long fleshy pedicle (the right end). Unusually for brachiopods, they are infaunal, living with the pedicle vertically down in the sediment. They can flex this pedicle to move their valves up and down in the sediment, maintaining access to seawater which they filter for their food. They have been doing this for hundreds of millions of years with little evolutionary change. Since they are infaunal, they can leave evidence of their burrowing in the sediments, making a particular variety of trace fossil. This is where our story begins.

While doing fieldwork in the Middle Jurassic Carmel Formation this summer with Team Utah 2022 near St. George, Utah, I found numerous small slabs of sandy-oolitic limestone with roughly circular pits a centimeter or so in diameter (above).

This is the steep slope where these particular trace fossils are found. This is our Dammeron Valley location (C/W-773) in “Member D” about a meter above the C/D boundary. It is in the record of a significant transgression Lucie Fiala (’23) is currently studying for her Senior Independent Study project at Wooster. It is also a part of Vicky Wang‘s (’23) Carmel trace fossil Senior IS project.

As shown above back in the Wooster lab, the circular pits have an inverted cone shape, with their diameters decreasing evenly with depth. Most are circular to oval in cross-section.

Critically, some, like the largest shown above, are oval with sharpish ends, which matches what we expect to see with the compressed valves of lingulid brachiopods moving vertically in the top couple centimeters of the sediment on the seafloor. Now, do they also show traces of the long pedicle below them? Of course they do.

This is an eroded cross-section showing the conical pit and a constriction on the bottom end.

And here is the smoking gun for a lingulid trace. I sawed through one of the pits, which exposed the long sediment-filled trace of the pedicle. Several other cuts showed that this a repeated feature. Lingulid traces they are, and the first found in the Carmel Formation. Note that the sediment here consists of sand-sized particles composed mostly of ooids, then quartz sand grains, and finally fragments of crinoids (the little white bits). Helpfully, the sediments also contain fragments of phosphatic brachiopod shells.

What is the official ichnotaxonomic name for a lingulid brachiopod trace fossil? This is where the first, and most significant, disappointment enters the narrative. In 1976, Eugene Szmuc of Kent State University, Richard G. Osgood of The College of Wooster (and at the time my undergraduate academic advisor), and Deborah Meinke, a Wooster alumna, published a paper describing lingulid trace fossils from the Devonian of Ohio. They christened them Lingulichnites. Unknown to these authors, William Hakes at the University of Kansas was also working on lingulid trace fossils, and also in 1976 he published his name for them: Lingulichnus. Two names for the same trace fossil published in the same year. Which name to use? Or in official terms, which name has priority and which is a junior synonym not to be used except for historical purposes? Turns out the Hakes publication appeared one month before the Szmuc et al. paper. Lingulichnus has priority and is the accepted name for these lingulid trace fossils. Such is science, but the added disappointment is that the issue of Lethaia that carried the Szmuc et al. (1976) paper was delayed in publication by a bad batch of printing paper — a delay of more than a month, thus losing priority on the name. Szmuc et al. had to write a short note in 1977 officially consigning Lingulichnites to junior synonym status. The editors apologized in a statement published with that note.

The second, and minor, disappointment is all on me. I got so excited about these lingulid traces in the Carmel Formation that I started a project to describe them as a new ichnospecies of Lingulichnus. My hypothesis was that these had cone-shaped tops because the brachiopod was twisting its pedicle as it fed, carving out a roughly circular to oval pit different from the sharp-ended slits in the typical Lingulichnus. I did measurements, statistics, saw cuts and photographs as I explored these structures. Lots of exciting work. I should, though, have done my literature searching first …

This magnificent figure above is from Zonnenveld et al. (2007). This paper, along with Zonnenveld and Pemberton (2003), provides an extraordinary analysis of lingulid brachiopod trace fossils, including new ichnospecies and accounting for all sorts of behavior, even twisting the pedicle. If I had read these papers earlier I would have saved myself a lot of work, work which would have had no novelty for publication. A minor disappointment, but I did learn a lot about lingulids in the process.

Ultimately the importance of these trace fossils for our Carmel Formation paleoenvironmental analysis is that Lingulichnus is the kind of trace that shows an animal living in sediments that were moving frequently enough that it had to adjust its position to increased or decreased sediment levels. That tells us something about the initial stages of this transgression. No research is ever wasted.


Hakes, W.G., 1976. Trace fossils and depositional environment of four clastic units, Upper Pennsylvanian megacyclothems, northeast Kansas. University of Kansas Paleontological Contributions, Article 63, p. 1-46.

Szmuc, E.J., Osgood, R.G. and Meinke, D.W., 1976. Lingulichnites, a new trace fossil genus for lingulid brachiopod burrows. Lethaia 9: 163-167.

Szmuc, E.J., Osgood, R.G. and Meinke, D.W., 1977. Synonymy of the ichnogenus Lingulichnites Szmuc, Osgood & Meinke, 1976, with Lingulichnus Hakes 1976. Lethaia, 10(2), pp.106-106.

Zonneveld, J.P., Beatty, T.W. and Pemberton, S.G., 2007. Lingulide brachiopods and the trace fossil Lingulichnus from the Triassic of western Canada: implications for faunal recovery after the end-Permian mass extinction. Palaios 22:74-97.

Zonneveld, J.P. and Pemberton, S.G., 2003. Ichnotaxonomy and behavioral implications of lingulide-derived trace fossils from the Lower and Middle Triassic of Western Canada. Ichnos 10: 25-39.

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Alaska Day 5 – Juneau

There are two legs to the project this summer. Lilly and Fred are headed back to the Wooster Tree Ring Lab with samples from Kake and Jacob and Jack have arrived. Jack, Jacob, Nick and I will now travel to Glacier Bay for 10 days of sampling ancient forests. As a warmup, the group hiked to Mendenhall Glacier. The glacier is rapidly retreating but we are still able to find solid ice to take the team photo.

The hike to the glacier is great and the day was perfect.

Mendenhall Glacier from the forefield.

Fred found some ancient stumps and logs likely dating back to about 2.5 ka, the forests continue to be unearthed with the ice recession.

The West Mendenhall Trail has a variety of streams and falls.

Across the glacial lake is Nugget Falls and part of the group poses next to this popular stop.

The group getting organized and enjoying the katabatic breeze.


After all it was the 4th of July.

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Alaska Day 4

A view from the porch of the Forest Service cabin out into the Sound.

Day 4 started in the intertidal zone at low tide. Identification of the various intertebrates included the limpet above.

This large cockle was squirting water through its syphon and was easily captured.

Sea stars are abundant – this one was named Patrick.

This sea anemnome was filtering through the rocks.

This squillamantis was a mystery and most of us had never encountered it before.

Sea cucumbers were abundant and colorful.

Another sea cucumber.

Another sea star with tenticles flaring.

Beach asparagus was a big hit and we plan to pickle a few jars.

Here is a chiton called a gumboot by the folks in Kake.

After the beach we went to get coffee at Tribal Grounds.

Berry picking under the shadow of Alaska’s tallest totem pole – here salmonberries and strawberries were picked for the elders in town.

The afternoon was spent coring living and dead yellow cedar trees – here Lilly is coring a living cedar, many that are over 500 years old.

The Wooster group at the cedar site.

The final photo of the two groups combined at the Lodge was the farewell. More is to come as Lilly and Fred return to the tree-ring lab to work on the red and yellow cedar cores.

A bear passed by the lodge on his way to work.


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Alaska Day 3

Coring the furthest north stand of Western Redcedar (Thuja plicata).

Celebrating another successful core extraction by Siah.

Banana slug on the forest floor.

Mounting the redcedar cores at the Forest Service cabin. Also examining cores taken in previous years.

Long Beach at Macartney Point. An afternoon of tossing the frisbee and trash cleanup.

Salmonberry and blueberry ensemble.






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Alaska Day 1

We arrived in Juneau on Sunday flying from Cleveland to Juneau. The goal of the trip is to work with the AYLS youth group of Kake Alaska (formerly known as TRAYLS) coring trees with both the Wooster group of faculty, staff and students and AYLS learning more about the forests of Southeast, Alaska. Lilly took a great picture of the dock on Auke Lake just down from our lodging at the University of Alaska Southeast campus. We spend two nights in Juneau getting staged for our trip south.

Our first full day was a break-in hike up the Thunder Ridge trail.

It was slow going at first – we took a few cores on the way sampling mountain hemlocks along the way to keep in shape.

Fred and Lilly led the way.

There was an endless up hill.

Tuesday was a travel day – we took a short hour flight from Juneau to Kake to meet up with the AYLS group in Kake (more to come).

Kake from the air – another day of brilliant sunshine on the water.

Irises grace the area around the lower Mendenhall River in Juneau.




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