Wooster Geologist at Niagara Falls

August 10th, 2015

1 American FallsLOCKPORT, NEW YORK (August 10, 2015) — I know, such a cliché image, but you know it had to happen on this trip. This morning Andrej Ernst and I packed up 78 pounds of bryozoan-rich Silurian rocks and mailed them to Kiel, Germany. (Thank you to the kind and patient people at both UPS and the USPS.) We celebrated our success with a trip to Niagara Falls. Above is the view of American Falls from Prospect Point.

I can’t recommend going to Niagara Falls at the height of the season, especially since the parking system seems to be in disarray and run by 14-year-old boys, and the lines are like Disneyland on the Fourth of July. Nevertheless, there is no way I’m going to let the German visitor spend a week in Niagara County and not see the main attraction.

2 Cave of the Winds MWYellow plastic ponchos and sandals are for the regular public, not geologists.

3 Andrej wet 081015Andrej is very pleased to intimately meet the water pouring over the falls. We tried not to remember that it all flows from Lake Erie.

Tomorrow I take Andrej to a Buffalo hotel where he will wait until his flight back home to Germany. I then make the long drive back home to Wooster. A successful end to my 2015 field season. Lots of ideas now for next year!

Please use the tag NY2015 for a link to all the posts on this trip.

For our records, here are the localities visited on this trip —

GPS # Location Latitude, Longitude Notes
112 Caleb’s Quarry N 43.20092, W 78.46021 Bryozoans in Lewiston E
113 Gasport Quarry N 43.19973, W 78.54436 Lewiston E, Burleigh Hill contact
114 Gasport Road N 43.19144, W 78.57550
115 Niagara Rd/Railroad North N 43.17556, W 78.72086 Top of Lewiston B
116 Niagara Rd/Railroad South N 43.17377, W 78.72364 Top of Lewiston E
117 Cherokee Unconformity N 43.18355, W 78.70266
118 Craine Street N 43.17995, W 78.71020 Gasport Formation, glacially-truncated fossils
119 Hickory Corners parking N 43.18435, W 78.75449 Reynales, Hickory Corners Member; Aeronian
120 Niagara Gorge Lewiston B N 43.14851, W 79.04095 Lewiston B; Sarle Reefs
121 Buffalo Creek South N 42.84728, W 78.60229 Wanakah; Rhipidomella beds
122 Buffalo Creek North N 42.84871, W 78.60202 Wanakah; Pleurodictyum beds
123 Bethany Center N 42.93250, W 78.13408 Centerfield Limestone Member, Ludlowville
124 Hickory Corners SR93 site N 43.18464, W 78.75394 Reynales, Hickory Corners Member; Aeronian
Jeddo Creek Tributary N 43.20175, W 78.47350 Carl’s “washings” locality; top of Lewiston B

Final day in the Silurian of New York

August 9th, 2015

1 Caleb new excavationLOCKPORT, NEW YORK (August 9, 2015) — This was the last day in the field for Andrej Ernst and me. We met all our goals (collecting bryozoans from the Rochester Shale, finding sclerobionts anywhere, and learning more about New York fossil localities) and had a great time. Now we have two days left to pack our specimens, ship those going to Germany, and review our notes. We will probably get some time tomorrow to see Niagara Falls!

We worked this morning in Caleb’s Quarry, a place we visited on our first day. Paul Chinnici, one of the fossil enthusiasts working this quarry, was our generous host. We were impressed with how much has changed in just the five days since our last time here. The large excavation above, for example, is new. This is fossil-collecting at a very large scale!

2 Caleb blocksAndrej searched for more bryozoans in the top layers of the shales while I studied these blocks of resistant calcareous siltstones and limestones. They are from a layer about midway down in the quarry. The shales erode to clay around them while they stand in relief.

3 Caleb block plan viewThe blocks have excellent trace fossils, including Chondrites seen in this bedding-plane view on the top of a block. Chondrites was made by small animals mining the sediments for deposited organic material.

4 Caleb block side viewThe trace fossils cut down into the siltstone, seen here in side view. The tunnels are filled with a clay-rich sediment that weathers a lighter color, giving us this contrast.

5 Caleb turbiditeMany of the blocks show a turbidite-like structure, with coarse shelly debris at the base and cross-bedded siltstone above. This may mean that the deep-waters that accumulated the clays to make the gray Rochester Shale were occasionally disturbed by massive turbidity flows of a sediment-water slurry. Were these triggered by storms or seismic events connected to orogenies to the east?

6 Caleb block stone in placeBecause of the recent excavations at Caleb’s Quarry, we were able to see this persistent calcareous siltstone in its stratigraphic context. It is here marked by the hammer. Note the gray shales above and below.

With this last observation, our fieldwork is officially done!

7 Paper pulp factory Lockport CaveDuring the afternoon we again visited the Erie Canal locks in Lockport. This time we took a tour of “Lockport Cave”, which is really a set of tunnels dug in the mid-19th century to channel river water through “races” to power factories. It is quite an ingenious use of hydropower before electricity. Above are the remains of the last of these water-powered factories, a paper pulp mill.

8 Lockport Cave entranceWe entered the main tunnel through a massive pipe that used to bring fast-flowing water to water wheels in the paper factory. The pipe is eight feet in diameter, and the water flowed at about 12 miles per hour.

9 Lockport Cave entrance pipeThis is the only one of my interior photos to succeed. The place was fascinating, even if it was cool, damp and dark. The trip included a short underground boat ride along a narrow water channel.

10 Upside-down railroad bridgeFinally, just because it is cool, here is the Lockport Railroad Bridge over the Erie Canal. It is called “the upside-down bridge” because the trusses are underneath the tracks. The legend is that the railroad company built the bridge this way to limit the height of boats on the canal, thus limiting its competition for cargo transport!

Return to the Silurian of New York

August 8th, 2015

1 Cichorium intybus SR 93 585LOCKPORT, NEW YORK (August 8, 2015) — Andrej and I began some deep collecting of Silurian localities in the Lockport area today in our survey of the bryozoan and sclerobiont faunas. The sites are, shall we say, not the most attractive, so let’s start with this common but gorgeous flower along the roadsides in western New York: Cichorium intybus (chicory). It is an invasive perennial from Europe that now has a global distribution. It has its uses as a coffee substitute, livestock feed, and salad stock. I love the color and serrated leaves.

2 Andrej Hickory CornersAnd here is why we lead with a flower. Andrej Ernst is sorting through samples from the Hickory Corners locality on State Route 93 in Lockport. The fossiliferous limestone here is the Hickory Corners Member of the Reynales Formation (Lower Silurian, Aeronian). The bryozoans are wonderfully diverse, and the top of the unit is a bored carbonate hardground. We happily collected here most of the morning, despite the trash and traffic.

3 Lewiston B beds Niagara RoadWe returned to a site along railroad tracks at Niagara Street in Lockport to collect from the Lewiston Member, part B, of the Rochester Shale. Again, the bryozoans here are fantastic, including my new favorite, a delicate cyclostome named Diploclema.

4 Lewiston E Burleigh Hill Shale LaFarge QuarryOur last site of the day was along the entrance road to a quarry. With all the surrounding rock, the only fossiliferous horizon is exposed in a shallow drainage cut in the road itself. Andrej is pulling a few bryozoans from the top of Lewiston Member, part E, of the Rochester Shale. The thick shales above him are the Burleigh Hill Formation.

5 Erie Canal at LockportWhen our work was done for the day, we became tourists and visited the Erie Canal locks in Lockport. (Hence the name!) This is a view looking east from the bottom of the two-lock sequence. We wanted to see the locks actually transport a boat, but it was a slow Saturday afternoon.

6 Erie Canal Lock LockportA view of the massive doors upstream of one of the modern locks. The engineering feats here date back to the early 1820s.

7 Crinoidal cross-sets Erie CanalGeology is evident here too. This is a block of crinoidal limestone showing cross-stratification. Many of the older buildings in Lockport are made of Silurian stone excavated to create the Erie Canal.

Into the Niagara Gorge

August 6th, 2015

1 Lewiston-Queenston Bridge 080615LOCKPORT, NEW YORK (August 6, 2015) — It holds one of the strongest river currents in the world, the gorge of the Niagara River below Niagara Falls. That tremendous flow has cut a deep canyon through the Silurian rocks of the region, providing a superb opportunity for geologists to see the local stratigraphy and paleontology. Today our team walked into the gorge from Lewiston, New York, to explore the section. Carl Brett was our guide. Above is a view of the gorge at the Lewiston-Queenston Bridge that joins the USA on the right with Canada on the left. The forests are plenty dense, but there are rocks in those steep walls.

2 Gorge trailWe hiked along the Gorge Trail on the USA side upriver from Lewiston. The trail is actually an old road built for transport of construction materials used for the hydroelectric dams upriver.

3 Gorge block 080615We learned most of the geological context by examining fallen blocks along the trail. This was an interesting way to see the stratigraphy because the different formations dropped blocks randomly along the path.

4 AE080615I tried to get a surreptitious picture of my German colleague Andrej Ernst.

5 Grimsby crossbedsThe Grimsby Formation (Lower Silurian, Llandoverian) is a sandstone that has numerous sedimentary structures, including nice cross-sets.

6 Kinneyia Grimsby Niagara GorgeAndrej found this nice specimen of an enigmatic feature called Kinneyia. It may be a function of gas build-up underneath microbial mats on the ancient seafloor. I’ve always called it “elephant skin”.

7 Niagara Gorge section 080615A view of the gorge wall above us.

8 Rochester collecting Niagara GorgeWhen the trail reached the Rochester Shale, we spent some time searching it for fossils. The most common finds were cystoids (especially Caryocrinites) and the odd coronoid Stephanocrinus.

9 Andrej Carl 080615Andrej Ernst and Carl Brett on the Rochester Shale outcrop in the Niagara Gorge. Andrej noted many neglected bryozoans in the fossil fauna exposed here.

10 Sir Adam Beck Hydroelectric Generating StationsOur final stop was opposite the Sir Adam Beck Hydroelectric Generating Stations built on the Canadian side of the gorge. It is an awesome feat of engineering, and a prodigious amount of concrete.

We had an excellent time in the Niagara Gorge. I was at last able to see some of the nuances of Silurian stratigraphy that Carl Brett was explaining. As you can see, the weather was ideal.

We said goodbye to Carl at the end of the day as he departed for fieldwork in nearby southern Ontario.


Wooster Geologist in New York

August 5th, 2015

1 Calebs Quarry 080515LOCKPORT, NEW YORK (August 5, 2015) — What looks like an ordinary commercial quarry above is actually quite unusual. It is an excavation done entirely by amateur paleontologists (“citizen scientists”) to collect and preserve fossils from the Rochester Shale (Upper Silurian, Wenlockian). The story of Caleb’s Quarry is well told in the linked American Museum of Natural History article. It is near Lockport, New York, and one of the most famous fossil sites in the region. I’m lucky to be here.

This late summer expedition to New York is to help my German friend Andrej Ernst (University of Hamburg/University of Kiel) collect bryozoans from the Rochester Shale. This bryofauna is inadequately described for phylogenetic and biogeographic analyses, so Andrej has a grant to do the deed from outcrop sampling to preparation, analysis and publication. While assisting Andrej, I am also scouting out new localities for future geology Senior Independent Study projects at Wooster. We will be in Niagara and Erie Counties for a week doing this work.

2 CarlCalebsAbsolutely critical to the project is the field advice and direction of Carl Brett (University of Cincinnati). Carl is without peer when it comes to many paleontological and geological topics, but for the Silurian of New York he is one of the gods. Carl grew up in the region and has been studying the rocks and fossils since he was a young teenager. He gave us two days of magnificent stratigraphic instruction, and he introduced us to the amateur team digging at Caleb’s Quarry. We were also joined for three days by Brian Bade, a citizen scientist from Ohio with an extraordinary passion for fossils, along with deep knowledge and appreciation for how science works.

3 FredandCarlCalebsFred Barber, one of the excavators at Caleb’s Quarry, is here showing Carl Brett magnificent crinoids collected from this locality.

4 Crinoid Calebs 080515The gray shale matrix is homogenous and soft enough to be removed from the fossil by an expert preparator. This crinoid shows outstanding preservation down to the pinnules on its arms.

5 Bryozoan Calebs reconstructedOf course, Andrej and I are most interested in the bryozoans from Caleb’s Quarry. Here is a beautiful specimen that has been carefully reconstructed.

6 StriispiriferCalebsI found these brachiopod-rich beds intriguing. Striispirifer is a new name to me.

7 DalmanTriloCalebsTrilobites are always the stars of Paleozoic fossil sites like this. While we were at the quarry we watched one of the excavators (Kent Smith) unearth this gorgeous specimen. I believe it is Dalmanites limulurus.

8 ChondritesCalebsThe trace fossils here are very interesting. There may be project possibilities with this ichnofauna because of the diversity present at the quarry and the bedding plane exposures. This is the trace fossil Chondrites.

9 Jungle Jeddo tributaryAfter our quarry visit today we then stopped at some other exposures of the Rochester Shale. This scene shows what fieldwork is like without quarries and roadcuts! We are here along a tributary of Jeddo Creek, at the top of Lewiston Member B of the Rochester Shale. Hard to tell, eh?

10 Brian Jeddo Tributary Lewiston BHere Brian Bade is examining a deeply weathered section along the creek. Years ago Carl Brett took advantage of this disaggregation of the Rochester Shale to sieve the sediment for small fossils. He has generously given us the “washings” from this cut, which represent months of his work as a graduate student. They are loaded with tiny bryozoan bits, along with many other taxa.

11 Cherokee UnconformityWe ended the day with a look at several other outcrops in the Lockport area. The impressive contact here between the massive sandstone and the underlying red shales is called the Cherokee Unconformity. It is a megasequence boundary correlated across most of North America. It was thought until recently to be the Ordovician-Silurian boundary, but now all you see in this image is considered latest Ordovician.


Wooster’s Fossils of the Week: A Silurian encrinite from southwestern Ohio

May 22nd, 2015

BrassfieldEncrinite585_041915The above rock was collected on our Sedimentology & Stratigraphy class field trip last month. It is an average piece of weathered Brassfield Formation (Early Silurian, Llandovery) from Oakes Quarry Park near Fairborn, Ohio (N 39.81472°, W 83.99471°). It is made almost entirely of crinoid fragments, and has a pleasant pinkish hue, most of which comes from the crinoid bits themselves. If you look closely you can see crinoid thecal plate fragments as well columnals and pluricolumnals.

This kind of limestone in which echinoderm ossicles make up the bulk of the grains is known as an encrinite. I first learned about encrinites from my colleague Bill Ausich of The Ohio State University, who has written the best assessments of encrinites on a regional scale. Encrinites are well-washed biosparite grainstones typically deposited between fair weather and storm wave bases on shallow shelves in low latitudes. They are surprisingly common from the Ordovician into the Jurassic, but then the disappear from the rock record as crinoids declined in abundance in shallow environments.

We’ve seen encrinites before in this blog from the Silurian of Estonia, the Triassic of Poland, and the Jurassic of Utah.


Ausich, W.I. 1986. Early Silurian inadunate crinoids (Brassfield Formation, Ohio). Journal of Paleontology 60: 719-735.

Ausich, W.I. 1997. Regional encrinites: a vanished lithofacies. In: Paleontological events: stratigraphic, ecologic and evolutionary implications, p. 509-519. Columbia University Press, New York.

Ausich, W.I. and Deline, B. 2012. Macroevolutionary transition in crinoids following the Late Ordovician extinction event (Ordovician to Early Silurian). Palaeogeography, Palaeoclimatology, Palaeoecology 361: 38-48.

Hunter, A.W. and Zonneveld, J.P. 2008. Palaeoecology of Jurassic encrinites: reconstructing crinoid communities from the Western Interior Seaway of North America. Palaeogeography, Palaeoclimatology, Palaeoecology 263: 58-70.

Tang, C.M., Bottjer, D.J. and Simms, M.J. 2000. Stalked crinoids from a Jurassic tidal deposit in western North America. Lethaia 33: 46-54.

Wooster’s Fossil of the Week: A ptilodictyine bryozoan from the Silurian of Ohio

May 15th, 2015

Phaenopora superba Brassfield 585The fossil above was found by Luke Kosowatz (’17) on our Sedimentology & Stratigraphy class field trip last month. We were measuring and sampling the Brassfield Formation (Early Silurian, Llandovery) near Fairborn, Ohio, and Luke pulled this beauty out of the rubble. This limestone is full of echinoderms and corals, so this lonely bryozoan was immediately a star.
Peela 050815This is the specimen that we sectioned and made an acetate peel from last month. The interior view, shown above, was critical to its identification. This peel was made perpendicular to the surface. It shows that the bryozoan is bifoliate, meaning it has two sides with zooids (the filter-feeding bryozoan polypides) and stood upright on the seafloor like a fan or leaf. Both sides had the characteristic bumps called monticules.
Phaenopora closerThe next critical view is this close-up of a slightly weathered surface of the bryozoan. It shows a regular arrangement of the larger zooecia (autozooecia) with two smaller zoooecia (metazooecia) between each pair. These clues enabled my friend Andrej Ernst, a paleontologist and bryozoan expert in the Department of Geosciences at the University of Hamburg, to identify this bryozoan as the ptilodictyine Phaenopora superba (Billings, 1866).
CNSPhoto-GEOLOGISTElkanah Billings (1820-1876) originally described this bryozoan species in 1866. He was Canada’s first government paleontologist, and he very much looked the part. Billings was born on a farm near Ottawa. He went to law school and became a lawyer in 1845, but he gave up dusty books for the life of a field paleontologist. In 1856 Billings joined the Geological Survey of Canada. He named over a thousand new species in his career. The Billings Medal is given annually by the Geological Association of Canada to the most outstanding of its paleontologists.


Billings, E. 1866. Catalogues of the Silurian fossils of the island of Anticosti: with descriptions of some new genera and species. Dawson brothers.

Ross, J.P. 1960. Larger cryptostome Bryozoa of the Ordovician and Silurian, Anticosti Island, Canada: Part I. Journal of Paleontology 34: 1057-1076.

Ross, J.P. 1961. Larger cryptostome Bryozoa of the Ordovician and Silurian, Anticosti Island, Canada: Part II. Journal of Paleontology 35: 331-344.

A beautiful day for Wooster Geologists in the Silurian of Ohio

April 18th, 2015

aDSC_5072FAIRBORN, OHIO–It’s field trip season at last for the Wooster Geologists. Several geology classes have now been out in Ohio, taking advantage of windows of spectacular weather. Today was one of those days for 25 students in the Sedimentology & Stratigraphy class. We returned to the Oakes Quarry Park exposures in southwestern Ohio (N 39.81472°, W 83.99471°). Three years ago here in April it was 37°F and raining. This year the conditions were perfect. We studied outcrops of the Brassfield Formation (Early Silurian, Llandovery) in the old quarry walls. The students measured stratigraphic columns of these fossiliferous biosparites as part of an exercise, and then explored the glacially-truncated top of the unit.

bDSC_5079The Brassfield is intensely fossiliferous. Large portions of it are virtually made of crinoid fragments. In the random view above you can see columnals, as well as a few calyx plates. This is why this unit is very popular among my echinodermologist friends at Ohio State.

DSC_5056Kevin Komara, Brian Merritt and Dan Misinay (Team Football) are here contemplating the quarry wall, planning how to measure their sections.

DSC_5063One of our Teaching Assistants, Sarah Bender, is here pointing out one of the many thin intercalated clay units in the Brassfield biosparites.

DSC_5065Fellow Californian Michael Williams directed the action. No, actually he’s doing the time-honored technique of following a measured unit with his finger as he finds a place he can safely climb to it and the units above. He is holding one of our measuring tools, a Jacob’s Staff. Why do we call them “Jacob’s Staffs”? Read Genesis 30:25-43. (Yes, today’s students are mystified by Biblical references.)

DSC_5066Here’s Rachel Wetzel, giving me a heart attack. Don’t worry, insurance companies and parents, she’s fine.

DSC_5068Rachel is again on the left. Team Ultimate Frisbee (Meredith Mann and Mae Kemsley) are in the front, and Sharron Ostermann is above. This is the recommended way to get to the top of the exposure!

DSC_5070We carried our lunches in “to go” boxes from the dining hall. Our Teaching Assistants Sarah Bender and Kaitlin Starr enjoyed a sunny picnic on the rocks.

yDSC_5077The top level of the quarry was cleared of soil and brush many years ago to expose a glacially truncated and polished surface of the Brassfield. Looking for glacial grooves and fossils here are (from the left) Tom Dickinson, Jeff Gunderson (another Californian!), Andrew Conaway, and Luke Kosowatz (who seems to also be making a little pile of rocks as a memorial to a great day).

zDSC_5074One of the many corals we found in the top of the Brassfield was this halysitid (“chain coral”), an indicator fossil for the Late Ordovician and Silurian.

Everyone returned safely to Wooster with their completed stratigraphic columns, lithological descriptions, and a few fossils. Thank you to Mark Livengood, our bus driver. Good luck to the other field trip groups later this month!

Wooster’s Fossil of the Week: A new crinoid genus from the Silurian of Estonia

March 13th, 2015

Velocrinus CD-interray lateralIt is my pleasure to introduce a new Silurian crinoid genus and species: Velocrinus coniculus Ausich, Wilson & Vinn, 2015. The image above is a CD-interray lateral view of the calyx (or head), with the small anal plate in the middle-top. (This will make more sense below.) The scale bar is 2.0 mm, so this is a small fossil. It was captured by the Crinoid Master himself (my friend and colleague Bill Ausich) from the Middle Äigu Beds of the Kaugatuma Formation (Upper Silurian, Pridoli) at the Kaugatuma Cliffs of Saaremaa Island, Estonia. It is described in the latest issue of the Journal of Paleontology. Here’s a link to the abstract. (This is the first issue produced by Cambridge University Press, so we’re honored to be part of publishing history.)
Velocrinus E-ray lateralHere is another view of the calyx, this time looking laterally at the E-ray.
AusichWilsonVinn_Fig3This figure explains the calyx views we see above. It is a plate diagram of Velocrinus coniculus. Imagine it as what the crinoid would look like if we could separate all its preserved ossicles and lay them out. The radial plates are black; the anal plate is shown stippled and marked with an “X”; the other letters indicate the particular rays. The artwork, and the images above, are from Bill Ausich.

The genus Velocrinus is defined this way in the paper: “Crotalocrinitid with a calyx cone shaped, lacking stereomic overgrowths, comprised of relatively large plates; infrabasals not fused, visible in lateral view; two anal plates; primaxil minute, not visible in lateral view; fixed brachials present; free arms not laterally linked; anus on tegmen; (nature of tegmen plating unknown).” This certainly is opaque to most readers. Trust us — it separates this new genus from all described before. Velocrinus is derived from the Latin term velo, which means to cover or conceal (think “veil”). It refers to the tiny primibrachials, which are not visible in lateral view. The species name coniculus refers to the cone-shaped calyx.
Kaugatuma070511Velocrinus coniculus is known only from the Kaugatuma Cliffs locality on Saaremaa Island. This is one of my favorite outcrops in Estonia. The extensive bedding-plane exposures are rare in the region. They show hundreds of holdfasts (essentially roots) of crinoids, some very large. The deposit was a relatively high-energy carbonate sand shifting through a forest of tall crinoids rooted in the sediment. Palmer Shonk (’10) did an excellent Senior Independent Study with rocks and fossils we collected from this place. The site shown above, by the way, was the location of a Soviet amphibious landing in November 1944.
KaugatumaCrinoidStem070511This is a close look at a bedding plane of Middle Äigu Beds of the Kaugatuma Formation. The crinoid stems are robust and abundant. Oddly enough, we’re still not sure what genus is represented by the large stems and holdfasts. The calyx of Velocrinus coniculus is far too small to have been associated with them. I suppose this means we need another expedition to Estonia!

This is the 1000th post in the Wooster Geologists blog.


Ausich, W.I., Wilson, M.A. and Vinn, O, 2012. Crinoids from the Silurian of western Estonia. 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.

Wooster’s Fossil of the Week: A stromatoporoid from the Silurian of Estonia

January 30th, 2015

Densastroma pexisumStromatoporoids are extinct sponges that formed thick, laminated skeletons of calcite. They can be very common in Silurian and Devonian carbonate units, sometimes forming extensive reefs. The stromatoporoid above is Densastroma pexisum (Yavorsky, 1929) collected from the Mustjala Member of the Jaani Formation (Silurian, Wenlock) exposed on Saaremaa Island, Estonia. It was part of Rob McConnell’s excellent Senior Independent Study he completed in 2010.
Densastroma pexisum sectionStromatoporoids are rather featureless lumps until you cut a section through them. Then you see their characteristic laminae of calcite. Looking very close you might also glimpse the tiny vertical pillars between the laminae. Identifying the species of stromatoporoid always involves a thin-section or acetate peel to discern the forms of the pillars and laminae.

In the upper left of the sectioned D. pexisum is an oval boring cut through the fabric of the stromatoporoid. This is likely the trace fossil Osprioneides kampto Beuck and Wisshak, 2008. This is the largest known Palaeozoic boring. It is relatively common in Silurian stromatoporoids of the Baltic region. Last year Olev Vinn, Mari-Ann Mõtus and I published a paper describing the same ichnospecies in large trepostome bryozoans from the Estonian Ordovician.
8 schematic drawing of Osprioneides kampto
This diagram of O. kampto is from Figure 8 of the Beuck et al. (2008) paper. The organism that made the boring was almost certainly a filter-feeding worm of some kind that gained a feeding advantage by placing itself high on a hard substrate.
Flügel in 7000 ts by Chris SchulbertDensastroma was originally named in 1958 by Erik Flügel (1934-2004). He combined the Latin densus with the Greek stroma, meaning “dense-layered”. (Yes, taxonomic purists will object to the mix of Latin and Greek in one name.) Flügel was a highly accomplished and diverse scientist who founded the Institute of Paleontology at the University of Erlangen-Nuremberg as well as the journal Facies. He is best known for his advocacy of detailed study of carbonate facies through petrography (“microfacies analysis“), developing a series of techniques and principles that I found very useful in my dissertation work. The above image is a fitting tribute to Erik Flügel made by Chris Schulbert. It is a portrait made of 7000 carbonate thin-sections!


Beuck, L., Wisshak, M., Munnecke, A. and Freiwald, A. 2008. A giant boring in a Silurian stromatoporoid analysed by computer tomography. Acta Palaeontologica Polonica 53: 149-160.

Flügel, E. 1959. Die Gattung Actinostroma Nicholson und ihre Arten (Stromatoporoidea). Annalen des Naturhistorischen Museums in Wien 63: 90-273.

Freiwald, A. 2004. Erik Flügel: 1934–2004. Facies 50: 149-159.

Vinn, O., Wilson, M.A. and Mõtus, M.-A. 2014. The earliest giant Osprioneides borings from the Sandbian (Late Ordovician) of Estonia. PLoS ONE 9(6): e99455. doi:10.1371/journal.pone.0099455.

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