Wooster’s Fossil of the Week: fusulinids (Upper Carboniferous of Kansas)

July 8th, 2012

They look like little footballs, at least the American variety of football. Fusulinids (the name indicating the fusiform shape) are about the size and shape of wheat grains. They were marine protists (single-celled eucaryotes) that lived from the late Early Carboniferous to the end of the Permian Period. Fusulinids are foraminiferans of the Superfamily Fusulinoidea named by Valerïan Ivanovich Möller (Imperial School of Mines, St. Petersburg) in 1878. They are critical index fossils for the Late Paleozoic, and I knew them intimately during my dissertation work in southern Nevada.

The shell of a fusulinid is very complex. It is made of a granular calcite wrapped along the axis of the football in a series of chambers with internal walls. Each coil wrapped completely over the earlier coils, making the shells involute. They are most commonly studied in section to reveal the internal complexity.
Cross-section of a fusulinid (Triticites) from the Permian of Iowa.

Fusulinid evolution was dramatic for a single-celled group. The earliest varieties were very small (one or two millimeters in length), and the later ones up to five centimenters long. Their internal features also increased in complexity, making each successive new species very easy to identify. This is why they are such good indications of geological time intervals. It is this biostratigraphic value that proved most useful to me as a young graduate student working in what seemed to me to be virtually featureless Carboniferous limestones.


Hageman, S.A., Kaesler, R.L. and Broadhead, T.W. 2004. Fusulinid taphonomy: encrustation, corrasion, compaction, and dissolution. Palaios 19: 610-617.

Möller, V.I., von. 1878. Die Spiral-gewundenen Foraminiferen des russischen Kohlenkalks. Mémoires de l’académie impériale des sciences de St-Pétersbourg, VII Série, Tome XXV, No. 9 et dernier.

Ross, C.A. 1967. Development of fusulinid (Foraminiferida) faunal realms. Journal of Paleontology 41: 1341-1354.

Stevens, C.H. and Stone, P. 2007. The Pennsylvanian–Early Permian Bird Spring carbonate shelf, southeastern California: Fusulinid biostratigraphy, paleogeographic evolution, and tectonic implications. Geological Society of America Special Paper 429, 82 p.

Wooster Geologist at Fort Ligonier, Pennsylvania: Choosing your ground geologically

June 5th, 2012

Fort Ligonier was built by the British in 1758 during the French and Indian War (or Seven Years’ War) along the Loyalhanna River in what is now Westmoreland County of southwestern Pennsylvania. It is a spectacular site today with a fully reconstructed fortification and an excellent museum. It gives us a chance to see how a military engineer used the local geology to build a successful fort in a difficult terrain.
The purpose of Fort Ligonier was to serve as the forward base for the capture of the French Fort Duquesne at the forks of the Ohio River. This was the most strategic site on the western frontier. The French and their Indian allies desperately wanted to preempt this attack by destroying the advancing British columns in the woods before they could assemble. The British and American colonists needed a robust road through the wilderness approaching Fort Duquesne, along with defensible strongholds. Fort Ligonier was the most critical of these positions, then, for both sides.
You would expect a fort to be built on the highest ground, yet Fort Ligonier is in a valley surrounded by commanding heights. The British knew, though, that the French and Indians did not have significant artillery in this theater. They could give up the heights so that they could use the Loyalhanna River as a defensible barrier against the inevitable infantry attacks. The site of Fort Ligonier also has small ravines on its other sides, forming a kind of moat. Most importantly, sandstone cliffs on the river side provide an unbreachable wall and an overview of the most likely approaches to the fort by the enemy. The British placed their largest cannon at the top of this cliff, surrounding them with an elaborate wooden stockade and sharpened obstacles.
The exposed rock of the Fort Ligonier cliffs is the Casselman Formation, a Late Carboniferous (about 300 million years old) mixture of shale, siltstone, sandstone and occasional coal beds. The particular unit here is a fine micaceous sandstone with cross-bedding. It was formed in an ancient river system. The cross-bedding and abundance of mica is a clue to this environment: the cross-bedding shows high-energy seasonal flooding; the mica flakes (the white grains seen below) show ebbs in water energy to near zero.
The French and Indians attacked Fort Ligonier on October 12, 1758, and very nearly took it. The British artillery sited on the sandstone cliffs was the deciding factor, though, and the besiegers retreated. Fort Ligonier swelled in population as British troops assembled for the attack on Fort Duquesne. In fact, in November 1758 it was the second largest city in Pennsylvania! (Among the British forces was the young George Washington.) The French saw the score and retreated from Fort Duquesne. The British captured this most strategic location and renamed the site “Pittsburgh”. Building and defending Fort Ligonier was key to this victory. By March 1766 the fort had served its purpose and was decommissioned.


Fowler, W.M., Jr. 2005. Empires at War: The French and Indian War and the Struggle for North America, 1754–1763. Walker & Company, 360 pages.

Sipe, H.C. 1971. Fort Ligonier and Its Times. Ayer Company Publishers, 699 pages.

Stotz, C.M. 2005. Outposts of the War for Empire: The French and English in Western Pennsylvania: Their Armies, Their Forts, Their People, 1749-1764. University of Pittsburgh Press, 260 pages.

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).


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