Now this is field trip weather

May 1st, 2012

WOOSTER, OHIO–It is now difficult to believe that we were measuring stratigraphic sections in a sleety thunderstorm on Saturday. Today the Tuesday lab of my Sedimentology & Stratigraphy course visited a local outcrop of the Logan Formation (Lower Carboniferous) to get more practice with stratigraphic techniques. What an enjoyable afternoon!

Students hard at work on the Logan Formation outcrop in Wooster. I’m hoping there’s no poison ivy in there.

Alex Hiatt and Cam Matesich looking very closely at the sandstone like good sedimentary geologists.

A set of male pine cones that have already distributed their pollen.

Andy Nash found this Eastern American Toad (Bufo americanus americanus) and our amphibian expert Ned Weakland captured it. Ned’s advisor Rick Lehtinen picked up a similar toad last semester on a short geology field trip. It made us feel all the more that we were in Spring at last.

Wooster’s Fossil of the Week: A scale tree root in its own soil (Upper Carboniferous of Ohio)

April 15th, 2012

Last week a local man, Larry Stauffer, brought in the above fossil for identification and then kindly donated it to the department. It is part of the root system of Lepidodendron, the “scale tree” of the Carboniferous Period. What is especially cool about it is that the rootlets, thin ribbon-like perpendicular extensions, are still attached. Usually they were lost quickly when the root was dislodged from its bed.

The well-preserved rootlets show that this bit of root is still in its original soil. Such a fossil soil is called a paleosol. These features are important in the rock record because they show ancient climate conditions, weathering profiles and sedimentation rates. Carboniferous paleosols like this are called seat earth.

The roots of Lepidodendron were given a separate generic name in 1822 by the French naturalist Alexandre Brongniart (1770-1847). He called them Stigmaria because of the regularly-spaced holes called stigmata. (You may know “stigmata” from an entirely different context!) The name was superseded by Lepidodendron once it was figured out how the roots, trunk, and leaves were connected.

Diagram of “Stigmaria ficoides”  from “Elements of Geology: The Student’s Series” by Charles Lyell (1871).

Brongniart is best known to me as one of the first biostratigraphers. He worked out the first divisions of the Tertiary Period (now known as the Paleogene and Neogene Periods) using fossils to mark time intervals. He also was the first to systematically study the trilobites at the other end of the geologic time scale. Brongniart did original geological mapping with the famous Georges Cuvier in the Paris region as well. He was a professor at the École de Mines and director of the Sèvres porcelain factories. I think he looks rather friendly in a Frenchy way.


Brongniart, A. 1822. Sur la classification et la distribution des végétaux fossiles en général, et sur ceux des terrains de sédiment supérieur en particulier. Soc. Philom., Bull., pp. 25-28 and Mémoires Du Muséum d’Histoire Naturelle 8: 203–240, 297–348.

Frankenberg, J.M. and Eggert, D.A. 1969. Petrified Stigmaria from North America: Part I. Stigmaria ficoides, the underground portions of Lepidodendraceae. Palaeontographica 128B: 1–47.

Jennings, J.R. 1977. Stigmarian petrifications from the Pennsylvanian of Colorado. American Journal of Botany 64: 974-980.

Rothwell, G.W. 1984. The apex of Stigmaria (Lycopsida), rooting organ of Lepidodendrales. American Journal of Botany 71: 1031-1034.

Wooster’s Fossil of the Week: A spiriferinid brachiopod (Logan Formation, Lower Carboniferous, Ohio)

April 1st, 2012

This brachiopod is one of the most common in the Logan Formation of Wooster, Ohio, so our students know it well from outcrops in Spangler Park and the occasional excavations in town. Four specimens of Syringothyris Winchell 1863 are visible in the slab above. The critter in the upper left is an earlier Fossil of the Week: the bivalve Aviculopecten subcardiformis. This suite of fossils is about 345 million years old (Osagean Series of the Lower Carboniferous).
We can’t identify the species of these Logan Formation brachiopods because the original shells dissolved away long ago. We are left with the sediment that filled the insides of the shells, producing what paleontologists call internal molds. Syringothyris belongs to the Order Spiriferinida, a group of elongate brachiopods that are punctate, meaning there are tiny holes penetrating their shells. Unfortunately this is one feature I can’t show you with internal molds!
Alexander Winchell (1824-1891) named and first described the genus Syringothyris. He was a geology professor at the University of Michigan for decades, specializing in Lower Carboniferous stratigraphy and paleontology. He was also the state geologist of Michigan. Winchell was one of the early American Darwinists, working hard to reconcile religion and science in the United States (with decidedly mixed results!).


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.

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.

Wooster’s Fossil of the Week: A syringoporid coral (Lower Carboniferous of Arkansas)

January 22nd, 2012

This specimen was collected from the Boone Limestone (Lower Carboniferous) near Hiwasse, Arkansas. It is a species of Syringopora Goldfuss 1826, sometimes known as the organ-pipe coral (but not the real organ pipe coral!).

Syringoporids are tabulate corals, a group that is always colonial. The corallites (tubes that contained the individual polyps) are vertical and were connected by small horizontal tubes, through which they shared common tissue. Some colonies had hundreds of corallites and built mounds up to a meter in diameter. Syringopora is the longest-ranging genus in the family, having started in the Ordovician Period and going extinct in the Permian.

Syringopora was first described by Georg August Goldfuss (1782-1848), a German paleontologist and zoologist. (Goldfuß is the proper spelling, if I can use that fancy Germanic letter.) He earned a PhD from Erlangen in 1804 and later in 1818 assumed a position teaching zoology at the University of Bonn. With Count Georg zu Münster, he wrote Petrefacta Germaniae, an ambitious attempt to catalog all the invertebrate fossils of Germany (but only got through some of the mollusks).
Georg August Goldfuß portrait by von Adolf Hohneck (1812-1879), 1841.


Girty, G.H. 1915. Faunas of the Boone Limestone at St. Joe, Arkansas. U.S. Geological Survey Bulletin 598.

Goldfuß, G.A. 1826-1844. Petrefacta Germaniae. Tam ea, quae in museo universitatis Regia Borussicae Fridericiae Wilhelmiae Rhenanae servantur, quam alia quaecunque in museis Hoeninghusiano Muensteriano aliisque extant, iconibus et descriptionibus illustrata = Abbildungen und Beschreibungen der Petrefacten Deutschlands und der angränzenden Länder, unter Mitwirkung von Georg Graf zu Münster, Düsseldorf.

Nelson, S.J. 1977. Mississippian syringoporid corals, southern Canadian Rocky Mountains. Bulletin of Canadian Petroleum Geology 25: 518-581.

Wooster’s Fossil of the Week: A scale tree (Late Carboniferous of Ohio)

January 8th, 2012

We haven’t had a plant fossil in this blog for awhile. Lepidodendron Sternberg 1820, pictured above, is one of the most common fossils brought to me in Wooster by amateur collectors. It is abundant in the Upper Carboniferous (Pennsylvanian) sandstones, shales and coals in this area. People sometimes call them “fossil snakes” because they are cylindrical and appear to have scales. Appropriately, the extinct plants they represent are called “scale trees” (the literal meaning of the genus name). The fossil above is an external mold of the trunk of this tree-like organism.
A plant as large and complex as Lepidodendron has many distinctive components that are often found separate from each other in the fossil record. These parts were given their own scientific names and only relatively recently were reunited into the genus Lepidodendron. The specimen above, for example, is traditionally known as Stigmaria and represents the roots of Lepidodendron.

From Book 15 of the 4th edition of Meyers Konversationslexikon (1885-90; figure 10). Lepidodendron is the tall tree on the left.

Diagrams of the trunk leaf scars (from Lesquereux, 1879).

Lepidodendron was up to 30 meters high in Carboniferous forests. It was tree-like, branching at the top and with a trunk covered with leaf scars. They are often called “club mosses” but are really related to modern quillworts (Isoëtes). They reproduced by spores, probably only once before death.
Lepidodendron was named and described by Kaspar Maria von Sternberg (1761-1838), a Czech naturalist who virtually founded the field of paleobotany. He was a philosophy student at the University of Prague when he began to collect fossils, minerals and plants, most of which eventually formed the nucleus of the National Museum in Prague. Oddly enough, he was also a theologian and received ordination in the Catholic church. He gave up his churchly duties early, though, and worked as a full-time scientist at various institutions in Central Europe. His description of Lepidodendron came from his deep studies of the fossils associated with coal mines in Bohemia.


Lesquereux, L. 1879. Atlas to the coal flora of Pennsylvania and of the Carboniferous Formation throughout the United States. Second Geological Survey of Pennsylvania, Report of Progress.

Sternberg, K.M., von. 1820-1838. Versuch einer geognostisch-botanischen Darstellung der Flora der Vorwelt.

Wooster’s Fossil of the Week: A Tully Monster! (Late Carboniferous of Illinois)

January 1st, 2012

We have several examples of one of the strangest fossils known: Tullimonstrum gregarium Richardson 1966 — otherwise affectionately known as the Tully Monster. The above specimen is from the Francis Creek Shale Member (Carbondale Formation) at Mazon Creek near Chicago, Illinois. Even if it wasn’t labeled this is an easy call: all Tully Monsters are from the same place!

The above diagram is from Johnson and Richardson (1969, Fig. 63). It shows just about all we know about the morphology of Tullimonstrum gregarium. It was a soft-bodied animal preserved as an outline in ironstone concretions split in half, so we usually get this long view. They have three body regions: head, trunk and tail. The head has a stalk-like proboscis with a sharp-toothed claw on the end. The anterior of the trunk has two bar organs of unknown function (you can just barely see them on our specimen). The tail has two fins.

Above is another of our Tullimonstrum specimens, this one folded inside its concretion. The transverse bar and one of the bar organs is visible.

Tullimonstrum cannot be placed in any known phylum. It may be some kind of worm (that’s always easy to say!), a mollusk, or somehow related to the arthropods, but it has no features sufficient to classify it. It looks a bit like Opabinia, a strange beast from the Cambrian with a similar clawed proboscis. We can at least say both were swimming carnivores!

The first specimen of what would become Tullimonstrum gregarium was found by an amateur collector, Francis Tully (pictured above courtesy the Field Museum). He was collecting in waste piles from strip mines near Chicago, splitting open ironstone concretions. The concretions formed around dead and decaying organisms in a shallow embayment during the Late Carboniferous. They preserved impressions and outlines of soft tissues, making the Mazon Creek Fauna a famous lagerstätte.

A charismatic fossil like the Tully Monster gets plenty of attention. One of the best visual reconstructions is on the sides of U-Haul trucks! It is also the state fossil of Illinois.

This entry is posted, by the way, on the one-year anniversary of Wooster’s Fossil of the Week. It is the 53rd in the series. Here is the very first post, which was on a gorgeous little Devonian auloporid.


Johnson, R.G. and Richardson, E.S. 1969. Pennsylvanian invertebrates of the Mazon Creek Area, Illinois: the morphology and affinities of Tullimonstrum. Fieldiana: Geology 12: 119-149.

Richardson, E.S., Jr. 1966. Wormlike fossil from the Pennsylvanian of Illinois. Science 151 (3706): 75–76.

Wooster’s Fossil of the Week: a medullosalean pteridosperm (Upper Carboniferous of northeastern Ohio)

October 23rd, 2011

It is time we had another fossil plant in this series. The above specimen is Neuropteris ovata Hoffmann 1826, a relatively common bit of foliage in the Upper Carboniferous of North America. This is a pteridosperm, more commonly known as a seed fern. They weren’t really ferns at all but fern-like plants with some of the first real seeds. They are usually reconstructed as trees, but were also known to be bushy or even like climbing vines.

The taxonomy (naming system) of fossil plants can be very complicated because different plant parts were given different names at different times. A single plant species, then, could have a list of names for its foliage, bark, roots, seeds, etc. The name Neuropteris usually thus refers to the leaves of this particular pteridosperm.

Neuropteris ovata is famous for its use in studies of the distribution of stomata on its leaf surfaces. Stomata, sometimes called guard cells, regulate gas exchange and moisture retention in vascular land plants. The density of stomata on N. ovata leaves in the Late Carboniferous may reflect changes in carbon dioxide levels and the expansion and contraction of tropical forests (Cleal et al., 1999).

Neuropteris ovata was named by Friedrich Hoffmann (1797-1836), a Professor of Geology at the University of Berlin. I wish I knew more about him because not only did he do considerable paleobotanical research, he was also well known for his work on volcanoes in Italy. You don’t see that combination very often!


Beeler, H.E. 1983. Anatomy and frond architecture of Neuropteris ovata and N. scheuchzeri from the Upper Pennsylvanian of the Appalachian Basin. Canadian Journal of Botany 61: 2352-2368.

Cleal, C.J., James, R.M. and Zodrow, E.L. 1999. Variation in stomatal density in the Late Carboniferous gymnosperm frond Neuropteris ovata. Palaios 14: 180-185.

Hoffmann, F. 1826. Untersuchungen über die Pänzen-Reste des Kohlengebirges von Ibbenbühren und von Piesberg bei Osnabrück. Archiv für Bergbau und Hüttenwesen 13: 266-282.

Zodrow, E.L. and Cleal, C.J. 1988. The structure of the Carboniferous pteridosperm frond Neuropteris ovata Hoffman. Palaeontographica Abteilung Palaophytologie 208: 105-124.

A Midday Biology & Geology Field Trip

September 28th, 2011

Geologist Greg Wiles and Biologist Rick Lehtinen in Spangler Park outside Wooster, Ohio.

WOOSTER, OHIO–Our colleague Rick Lehtinen in the Department of Biology had a great idea: how about a casual noon trip to the local Spangler Park to enjoy the plants, animals, rocks and streams? So Greg Wiles and I took him up on it and had a splendid couple of hours down in the gorge. We talked of ash trees, buried valleys, alluvial fans, salamanders and badgers. What an excellent break from grading!

Dr. Wiles showing where the creek flow goes from supercritical to subcritical.

An American Toad found by Dr. Lehtinen.

My contribution? An analysis of this beautiful set of bivalve, crinoid and brachiopod fossils from the Logan Formation (Mississippian).


Wooster’s Fossil of the Week: A Conulariid (Lower Carboniferous of Indiana)

July 31st, 2011

I have some affection for these odd fossils, the conulariids. When I was a student in the Invertebrate Paleontology course taught Dr. Richard Osgood, Jr., I did my research paper on them. I had recently found a specimen in the nearby Lodi City Park. It was so different from anything I had seen that I wanted to know much more. I championed the then controversial idea that they were extinct scyphozoans (a type of cnidarian including most of what we call today the jellyfish). That is now the most popular placement for these creatures today, although I arrived at the same place mostly by luck and naïveté. (I love the critical marks in that word! And yes, I always have to look them up.)

The specimen above is Paraconularia newberryi (Winchell) found somewhere in Indiana and added to the Wooster fossil collections before 1974. (The scale below it is in millimeters.) A close view (below) shows the characteristic ridges with a central seam on one of the sides.
Conulariids range from the Ediacaran (about 550 million years ago) to the Late Triassic (about 200 million years ago). They survived three major extinctions (end-Ordovician, Late Devonian, end-Permian), which is remarkable considering the company they kept in their shallow marine environments suffered greatly. Why they went extinct in the Triassic is a mystery.

The primary oddity about conulariids is their four-fold symmetry. They had four flat sides that came together something like an inverted and extended pyramid. The wide end was opened like an aperture, although sometimes closed by four flaps. Preservation of some soft tissues shows that tentacles extended from this opening. Their exoskeleton was made of a leathery periderm with phosphatic strengthening rods rather than the typical calcite or aragonite. (Some even preserve a kind of pearl in their interiors.) Conulariids may have spent at least part of their life cycle attached to a substrate as shown below, and maybe also later as free-swimming jellyfish-like forms.

It is the four-fold symmetry and preservation of tentacles that most paleontologists see as supporting the case for a scyphozoan placement of the conulariids. Debates continue, though, with some seeing them as belonging to a separate phylum unrelated to any cnidarians. This is what’s fun about extinct and unusual animals — so much room for speculative conversations!

[Thanks to Consuelo Sendino of The Natural History Museum (London) for correcting the age range of these fascinating organisms.]


Hughes, N.C., Gunderson, G.D. and Weedon, M.J. 2000. Late Cambrian conulariids from Wisconsin and Minnesota. Journal of Paleontology 74: 828-838.

Van Iten, H. 1991. Evolutionary affinities of conulariids, p. 145-155; in Simonetta, A.M. and Conway Morris, S. (eds.). The Early Evolution of Metazoa and the Significance of Problematic Taxa. Cambridge University Press, Cambridge.

A muddy but successful encounter with the Mississippian-Pennsylvanian boundary in southern Ohio

April 30th, 2011

Lindsey and Richa work their way up the Pennsylvanian section with their Jacob's staffs.

JACKSON, OHIO — Usually the Sedimentology & Stratigraphy class from Wooster meets no one at this Carboniferous outcrop on US 35 in Jackson County. This morning, though, we arrived to find geology students from Wright State University (under Professor David Dominic) hard at work on the section, and the clubhouse for the Apple City Motorcycle Club had a busy (and noisy) crowd as well. We waded right in and started measuring and describing the rocks.

The recent rains had their predictable effect on the shale units, producing a thick mud in some places, but we did well enough staying on the sandstones and conglomerates when we could. I noted that the outcrop is much more overgrown than when I first visited with a Sed/Strat class in 2000. (The better exposures made for better photography of the rock units, as you will see.) Here is another set of images from the 2009 field trip to this site.

This is one of the best places in the state to see the unconformity between the Mississippian and Pennsylvanian subsystems. It is a sharp disconformity above the Logan Formation siltstones and below pebble-rich sandstones of the Sharon Conglomerate equivalent. We drew measured stratigraphic columns through this interval and then met as a group on the top of the outcrop to assess the ancient depositional environments.

We all returned home safely with muddy boots and new ideas about the local stratigraphy.

Joe and Will confer on an outcrop of black, carbon-rich shale.

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