400-million-year-old trilobite fossil discovered on Honey Creek Parkway
by Carol Rosen
Historic Wauwatosa, Issue 255, Winter 2021
Sometimes a family outing can lead to an exciting discovery, especially when an observant 5-year-old girl is involved. Something caught Annie Misfeldt’s eye while walking with her dad and younger sister along Honey Creek Parkway. It was a well-preserved trilobite fossil. At first, Annie didn’t recognize the animal preserved in the rock, but after learning about the trilobite’s significance, she kindly offered it to the Wauwatosa Historical Society. Along with her parents and younger sister Mary, Annie enjoyed a Kneeland-Walker house tour when they donated the fossil in February.
The fossil trilobite is now the oldest artifact in our collection. We can proudly announce that it has lived in the neighborhood for over 400 million years! Annie’s fossil is a significant connection to Wauwatosa’s early geological past, and, as this five-year-old reminds us, there is something rather enchanting about holding the evidence of a 400 million-year-old creature in the palm of our hand.
The Trilobite is the State Fossil of Wisconsin
The landmass that became Wisconsin rested beneath a shallow sea 425 million years ago, in a period of geologic time called the Silurian. At thirty degrees south of the equator, the warm, tropical water was teeming with trilobites, an insect-like creature with an exoskeleton. As the animal inside it grew, the exoskeleton was shed and, with time, became fossilized.
The common trilobite (Calymene celebra) is the state fossil of Wisconsin. Trilobites are so-named for the three distinct lobes that divide their exoskeleton.
Wauwatosa’s Schoonmaker Reef
Annie’s trilobite fossil presumably came from the Schoonmaker Reef at the former Schoonmaker Quarry site near 66th and State Streets. Formed of sea creatures beneath the warm Silurian sea, the reef is comprised of a rock called dolomite, a form of limestone. Quarry workers burned the dolomite rock in wood-fired kilns to produce powdered lime, a product used primarily for whitewash, plaster, and fertilizer. The quarry also supplied crushed stone for roads and railroad beds.
The pit was filled when the quarry ceased operations in 1950. However, a part of the ancient reef is still evident along the north bank of the Menomonee River Valley. (The area is not accessible to the public.) The Schoonmaker Reef is known worldwide and serves as a textbook example of an ancient coral reef. Geologists today research the reef and continue to document the wide variety of fossils, including trilobites and other marine organisms that lived during the Silurian Period.
The Schoonmaker Reef is a National Historic Landmark, significant for its contribution to the interpretation of earth history and its association with prominent geologists of the early twentieth century. It is on the National Register of Historic Places.
Dr. Day and the Famous Fossils of Wauwatosa
Dr. Fisk Holbrook Day was the head physician for Milwaukee County and the first Superintendent of the County Hospital in the late 1800s. Sunnyhill Home, Dr. Day’s mansion, stands today at 8000 Milwaukee Avenue.
An avid fossil collector and amateur geologist, Day’s mansion included a “cabinet room” with built-in display cases to hold his boundless collection of fossils, many of which came from the Schoonmaker Quarry. The most renowned geologists of the day assessed the collection and collaborated with Dr. Day. His knowledge of local geology and his vast collection of fossils played an essential role in interpreting earth history worldwide.
Many fossils from Dr. Day’s collection are now at the Harvard Museum of Comparative Zoology, the Smithsonian Museum of Natural History, Chicago’s Field Museum, and the Greene Museum at UW-Milwaukee. Sunnyhill Home, built in 1874, is on the National Register of Historic Places.
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