New exhibit showcases world’s largest collection of Late Ordovician fossils

Cincinnati Under the Sea now open at Cincinnati Museum Center through October 26

CINCINNATI – Cincinnati Museum Center will highlight its impressive collection of Ordovician fossils in Cincinnati Under the Sea, an exhibit that runs through October 26.

Ordovician fossilsThere’s a fascinating amount of history beneath our feet in Cincinnati and the surrounding area. In fact, researchers have come from around the world to find in Cincinnati something that exists nowhere else on earth. Hidden within, and sometimes laying right on the surface of, the Ohio Valley’s rocks are the most abundant, diverse and best preserved invertebrate fossils from the Ordovician Period.
Cincinnati Museum Center houses the world’s largest collection of Late Ordovician fossils, including trilobites, crinoids and various cephalopods, as well as experts on their study. Brenda Hunda, PhD, Invertebrate Paleontologist at Cincinnati Museum Center, has studied these fossils and their impact.
“The Cincinnati region has one of the most extensive surface exposures of Ordovician strata in North America, if not the entire world,” says Dr. Hunda. “In the Cincinnati region we have a truly unique window to the past, one admired and studied by scientists from around the world.”
The exhibit will feature the Ordovician Diorama which was originally commissioned by the Cincinnati Society for Natural History for its museum building on Gilbert Avenue in 1957. The diorama was built by famous diorama artists Henri, Paul and George Marchand, who have also created dioramas for Chicago’s Field Museum of Natural History, the Smithsonian Institution and the University of Michigan Natural History Museum, as well as Yale, Harvard and Princeton. While the science used in the diorama is outdated in some regards, it remains an important part of history in the field of museum exhibits and as a reflection of the state of knowledge of paleontology at the time of its creation.
Over 450 million years ago during the Ordovician period, what is now Cincinnati was covered by a tropical sea where a vast array of sea life flourished. As the waters of the tropical sea receded during the end of the Ordovician period, it left behind one of the most complete marine records of Ordovician life. The rocks of the Ohio Valley are globally known as the Cincinnatian Series and contain the fossils of organisms that can offer a greater understanding of the meaning of biodiversity as it relates to both the Ordovician period and life today.
Marine biodiversity is higher now than at any time in the history of life on Earth. While the Cambrian Period (over 525 million years ago) was the time that the major limbs on the tree of life formed, the tree was filled out with numerous smaller branches during the Ordovician Period. The amazing diversity of animals preserved in our regional rocks marks the appearance of groups that came to dominate the marine ecosystems for the next 250 million years.
The Ordovician “boom” of increasing biodiversity was followed by the second greatest “bust” in Earth’s history at the end of the period. Hypothesized to be the result of the formation of glaciers in the southern hemisphere, oceans cooled and sea levels dropped. This pattern of boom and bust, which has been repeated several times in Earth’s history throughout the last 500 million years, provides scientists a window into the mechanisms that control biodiversity and can possibly tell us about the future of biodiversity on Earth.
The older the fossils are, the deeper in the ground they become buried, which would make finding fossils from 450 million years ago extremely rare and challenging. However, plate tectonics have exposed these Ordovician fossils once buried 1000-2000 feet below the surface. Collisions of tectonic plates in what would become North America resulted in an upwarping of the Earth along an arc near Cincinnati. This upheaved rock was continually eroded, stripping away strata above the Ordovician fossils. The glaciers that covered most of Ohio two million years ago washed away the remaining surface layers as they melted, exposing the fossils now studied by scientists from all over the world right here in the Cincinnati region.
Cincinnati Under the Sea was made possible through the support of the Cincinnati Dry Dredgers and Dan Phelps, president of the Kentucky Paleontological Society.
Cincinnati Under the Sea will run through October 26 in the Ruthven Gallery at Cincinnati Museum Center and is part of the #SummerOfScience at Museum Center. The exhibit is free and open to the public during regular museum hours. For more information on the exhibit please visit