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.

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. 

A prehistoric crayfish

A prehistoric crayfish, Enoploclytia porteri 

By Riley Newman

Grand Traverse Area Rock and Mineral Club Pebble Pups

 

Coquina

 Brody Dymond

Coquina is a type of sedimentary rock composed mostly of  shells and fossils. They can vary in hardness, ranging from crumbly to more hard like cement. The word Coquina comes from the Spanish word for “cockle” and “shellfish.” 

Coquina can be found all over the world. It forms when shells accumulate in shallow water areas where waves break such as beaches, bars, and raised banks. They are usually formed from salt water organisms, though Coquina that contain freshwater organisms can also be found. Some of the organisms that form Coquinas include mollusks, brachiopods, trilobites, and other invertebrates. The shells in Coquinas are usually 2mm or larger. 

The specimen I studied was an Ordovician period coquina limestone from the Cincinnati Arch near Liberty, Indiana. This specimen was totally packed with fossils and fossil fragments, and is very hard. Fossils included bryozoans, brachiopods, horn corals, and other organisms.

The photos below were taken by Brody with a digital microscope. 

Sources

https://legacy.igws.indiana.edu/compendium/harrodsburg-limestone

https://en.wikipedia.org/wiki/Coquina

https://www.sandatlas.org/coquina/ 

https://www.volusia.org/residents/history/volusia-stories/plantation-ruins/coquina-floridas-native-stone.stml 

Brody Dymond is a 5th grade science lover with a sketchbook full of Earth facts and creepy creatures.

Pachyteuthis densus

  by Brody Dymond

The Pachyteuthis densus was the fossil of a belemnite found in the Upper Sundance formation in Buffalo, Wyoming. Belemnites were a type of squid that lived many years ago. 

Image of the Pachyteuthis densus study specimen.
Photo date 2024 by B. Dymond.

Belemnites evolved to have a different way of protecting themselves from other types of marine animals. They were fast swimmers! Instead of having an external shell, their shell was internal, which helped them speed through the water to escape from predators. The internal shell of a belemnite is the part that was fossilized. There are three parts of the internal shell: the pro-ostracum, the phragmocone, and the rostrum. 

A group of belemnites was called a battlefield. The average size of the belemnites when they were alive was 30 - 50 centimeters long. Belemnites could be found worldwide in shallow waters close to the shore. Belemnites ate small fish, other marine animals, and possibly other belemnites. 

The belemnite’s tentacles did not have suction cups like squid today. Instead, they had curved hooks. While squids today have eight arms, the belemnites had ten arms and on each arm were 30-50 curved hooks. They used the hooks on their arms to capture and eat small marine animals. While some squids today are the same size as belemnites, some squids can get much bigger. For example, Colossal Squid can get up to 14 meters (46 feet) long! 

The Belemnites went extinct at the end of the Cretaceous Period roughly 65.5 million years ago. They died around the same time as the dinosaurs.  

A concept of what Pachyteuthis densus looked like
when it was alive. Artwork by B. Dymond.

The Grand Traverse Area Rock and Mineral Club’s First Pebble Pup Class Meets in March

In recent years, there has been a growing interest in geology and rockhounding among people of all ages. Whether it's the thrill of finding a mineral, rock, or the satisfaction of identifying a fossil specimen, there's something about rockhounding that captures the imagination.

Nowhere is this more apparent than in a new rockhounding class for children, the Pebble Pups, which has been a smashing success. The class, which is taught by passionate and knowledgeable instructors, has attracted a wide range of students, from 5 years old to 16 years old, who are eager to learn about the fascinating world of geology.  Two groups comprise this program. Elementary students are Pebble Pups. Middle school students and high school students participate as Earth Science Scholars. The older students work on research projects and help work with the younger students.

The first class met March 15, 2023. There were 5 Pebble Pups, 2 teenage Earth Science Scholars, 3 parents, 3 pup teachers, and 3 adult visitors. The Pebble Pup classes cover a range of topics, from basic geology and mineral identification to more advanced concepts like plate tectonics and geological time. Through a combination of lectures, hands-on activities, and field trips, students are able to deepen their understanding of the subject and develop a love for rockhounding that will stay with them for years to come.

Melanie Ackerman and Steven Veatch begin the first Pebble Pup lesson.
Pebble Pups meet from 5: 30 to 6:10 pm, the same night
the club meets at the VFW. Photo by Shelly Veatch.

One of the reasons the class has been so successful is the enthusiasm and dedication of the instructors. With years of experience in the field, they are able to share their knowledge and passion for the subject with their students, making the class engaging and informative. The instructors are Steve Veatch, Melanie Ackerman, and Michelle Peters. Nathan Peters, who participates as an Earth Science Scholar, is the program assistant. 

Melanie Ackerman is teaching the group how to write a short poem a
bout a rock, or mineral, or even a fossil. This mixes writing with science
to produce something artful, a poem. April is National Poetry Month
and the pups will participate. Photo by Shelly Veatch.

Another factor contributing to the success of the class is the way it is structured. By combining traditional classroom learning with hands-on activities and field trips, students are able to experience the subject in a variety of ways and develop a deeper understanding of the material.

But perhaps the most significant factor in the success of the class is the students themselves. With their natural curiosity and willingness to learn, they have embraced the subject and are eager to explore the world of geology and rockhounding.

For these students, the class is more than just an opportunity to learn about rocks. It's a chance to connect with the natural world, to discover the beauty and complexity of the earth, and to develop a sense of wonder and appreciation for the world around them.

As the success of this new rockhounding class demonstrates, there is a growing interest in geology and rockhounding among young people. By providing them with the tools and knowledge to explore this fascinating subject, we are helping to cultivate the next generation of rockhounds, and that's something for the Grand Traverse Area Rock and Mineral Club to be proud of.