Sunday, May 31, 2026

Studying A Fossilized Fern

 By Wyatt Maeder

The fossilized fern pictured in this paper (Figure 1) was found in the famous Mazon Creek fossil beds near Morris in Grundy County, Illinois. Paleontologists have identified this specific specimen as Ptychocarpus unitus. These renowned fossil beds have been actively studied since the middle of the nineteenth century.

Together, the matrix and fossil weigh 14 grams (0.5 ounces). The fossil and its surrounding matrix measure 3 centimeters (1.2 inches) in length. The fossil itself is 1 centimeter (0.4 inches) wide, while the matrix is slightly over 2 centimeters (0.8 inches) wide. This specimen is estimated to have formed during the mid-Pennsylvanian, roughly 309 million years ago.


Figure 1. Ptychocarpus unitus is an extinct fossil fern from the Pennsylvanian Period, preserved in the Mazon Creek Fossil Beds Photo date 2026 by Wyatt Maeder.

As you can see in figure 1 the fern fossil and matrix are a reddish-brown color. This means it is preserved in an ironstone concretion. Some studies show that there could be traces of organic carbon. I do not know this because I don’t have access to a gas spectrometer. 

 

Table. 1 Identification

Taxon:

Ptychocarpus unitus

Family:

Marattiaceae

Locality:

Mazon Creek, IL

Time Period:

 

Era

Paleozoic

Period

Middle Pennsylvanian


Thanks to exceptional preservation like that found in this fern, scientists can reconstruct ancient equatorial ecosystems, helping us learn more about late Paleozoic plant life, climate, and evolutionary history.

References
Hoskins, J. H. (1933). A Ptychocarpus Type of Fructification from Illinois. The American Midland Naturalist, 14(6), 726–728. https://doi.org/10.2307/2420131

Jennings, J. R., & Millay, M. A. (1979). Morphology of the fertile Pecopteris unita from the Middle Pennsylvanian of Illinois. Palaeontographica Abteilung B, 170(1-3), 51–65.

Tripp, M., Schwark, L., Brocks, J. J., Mayer, P., Whiteside, H. J., Rickard, W., Greenwood, P. F., & Grice, K. (2023). Rapid encapsulation of true ferns and arborane/fernane compounds fossilized in siderite concretions supports analytical distinction of plant fossils. Scientific Reports, 13(1), Article 19851. https://doi.org/10.1038/s41598-023-47009-8

About the author: Wyatt Maeder is a member of the Grand Traverse Area Rock and Mineral Club’s pebble pups. He is 11 years old and in 6th grade.

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Friday, May 15, 2026

Investigating an Ancient Roman Architectural Artifact

 By: Wyatt Maeder, Pebble Pup

This Roman tile fragment was found in the Roman Empire. The exact location is unknown. The tile may have covered a Roman home or business. It looks like a type of tile called a Tegula, a flat rectangular tile with raised flanges on the sides. The analysis of the artifact is in the following table.

Artifact Analysis: Roman Ceramic Tile

Probable origin

Roman

Estimated age

Circa 1,926 years old (100 CE)

Classification

Tegula (flat roof tile) with a raised flange on its side

Physical Dimensions

Weight

0.54 kilograms (1 lb. 3.1 oz)

Length

14 cm (5½ in)

Width

11 cm (4¼ in)


Composition & Mineralogy
Visual inspection suggests a fabric rich in quartz grains and iron oxide, which gives the ceramic its characteristic hue. The presence of dolomite is also suspected, likely introduced via sand temper. 

The tile may also contain natural clay from the Moza Formation, however, to determine this it would require laboratory analysis. Without a kiln-site test, it remains unclear if the material is refined clay from Rome or the Levant (Roman Judea). If is from Rome, it would likely be made from volcanic clays or muddy deposits from the Tiber Valley. Clays from around Rome are heavily influenced by the volcanic history of the Lazio region. Under a microscope, you would expect to see volcanic minerals such as augite (pyroxene), biotite, and sanidine (feldspar). Some Roman bricks even contain tiny fragments of volcanic tuff.  If it is from the sedimentary Moza Formation there would be dolomitic sand and you would see dolomite crystals and limestone fragments, but you would find zero volcanic minerals like pyroxene. Moza Clay typically fires to a light pinkish-orange, yellow-brown, or buff color. Because it is often rich in calcium carbonate (marl), it has a "creamy" look when fired at standard temperatures. Roman (Tiber) Clay: Often has a deeper red to reddish-brown hue due to the specific iron oxides found in the volcanic-rich Italian soils.


Figure 1. Side view of a fragment of a Roman tile, likely a roofing (tegula) tile. Photo date 2026 by W. Maeder. From the collection of Wyatt Maeder.




Figure 2. View of the top of the Roman tile. Note the red coloration and thickness of the tile. Photo date 2026 by W. Maeder. From the collection of Wyatt Maeder.


Manufacturing Process
Making a Roman roof tile was a lot like a professional version of making a clay project in a classroom, just on a much larger scale. First the workers dug up natural clay and mixed it with water. They added a little sand or crushed old bricks (called "temper") to keep the tile from shrinking or cracking when it got hot. Then the workers shaped the tile, they pushed the wet clay into a wooden frame, sort of like a large brownie pan. For a flat roof tile (tegula), they would use their fingers to create raised edges (flanges) on the sides so the tiles could lock together (see figure 1. and 3). Next it was time to stamp and dry the tile. While the clay was still soft, the workshop would often press a stamp into it—like a brand name—to show who made it. Then, they left the tiles out in the sun to dry out most of the water. Next, it is time to fire the kiln: The dry tiles were stacked inside a massive brick oven called a kiln. A fire was kept burning underneath for several days. Once the temperature hit around 900°C, the clay turned into hard, waterproof stone-like tile. Finally, after the kiln cooled down, the tiles were ready to be shipped to a construction site to keep a Roman house dry for hundreds of years.



Figure 3. Closeup of tile showing a raised flange on a Roman tile. Photo date 2026 by W. Maeder. From the collection of Wyatt Maeder.

Whether used as a protective roof covering or a component of a heating system, this artifact serves as a remarkable testament to the intersection of ancient mineralogy and ritualistic craftsmanship. Its enduring composition highlights the sophisticated engineering techniques that have allowed Roman architectural elements to survive for over a millennium.

Acknowledgment: Special thanks to my Mom for all the hard work she did to help me with this paper. Steven Veatch provided critical review. 

Reference and further reading:

Brodribb, G. (1987). Roman brick and tile: An analytical survey and corpus of surviving examples.

Cohen-Weinberger, A., Levi, D., & Beʾeri, R. (2020). On the raw materials in the ceramic workshops of Jerusalem, before and after 70 C.E. BASOR: Bulletin of the American Schools of Oriental Research, 383(1), 33–59. doi.org

Cohen-Weinberger, A., Martin, M., & Goren, Y. (2024, February 11). Israel-Palestinian Authority/central highlands/Moza clay. The Levantine Ceramics Project. https://www.levantineceramics.org/petrofabrics/32-israel-palestinian-authority-central-highlands-moza-clay.

Gerding, H. (2006). Early use of fired brick in Hellenistic and Roman architecture. In C. Mattusch, A. Donohue, & A. Brauer (Eds.), Common Ground: Archaeology, Art, Science and Humanities - Proceedings of the 16th International Congress of Classical Archaeology, Boston, August 23-26, 2003 (pp. 355-358). Oxbow Books.


Monday, October 20, 2025

Gabriel’s Report About Orthoceras

By Gabriel Minich

Orthoceras is an extinct relative of squids and octopi that lived during the Ordovician period. The name Orthoceras comes from Greek, meaning “straight horn,” which perfectly describes their long, pointy shells.


Orthoceras Features

  • The shell is straight and is shaped like a cone. It often reaches several feet in length.
  • The inside of an Orthoceras is divided into chambers by thin walls. A central tube ran through the chambers, which helped the animal float. 
  • Movement: Likely used jet propulsion by expelling water, similar to modern cephalopods.
  • Diet: Carnivorous, feeding on smaller marine organisms using tentacles and a beak-like jaw. 



Fossil Significance

  • Common Fossils: Their strong shells fossilized well, making Orthoceras one of the most commonly found Paleozoic fossils.
  • Global Distribution: Found in limestone and shale deposits across many continents. Scientific Value: Used as index fossils to help date rock layers and understand ancient marine ecosystems.   
  • And just for fun—Orthoceras fossils are often polished and sold as decorative items or jewelry due to their striking appearance. 


A polished Orthoceras specimen from Morocco. Photo date 2025 by Gabriel Minich.

About the author: Gabriel is 8 years old and is in third grade. He has a deep interest in science and recently joined Pebble Pups. 


Wednesday, September 24, 2025

Iris Wild Wins First Place Award

Iris won first place in the National Park Service art
competition that honored National Fossil Day and another
first place award from the American Federation of
Mineralogical Societies

 

Types of Rocks

 


Studying A Fossilized Fern

 By Wyatt Maeder The fossilized fern pictured in this paper (Figure 1) was found in the famous Mazon Creek fossil beds near Morris in Grundy...