Cincinnati Under the Sea in the Southern Hemisphere
Posted On: 05/01/2018 - 12:30pm, Posted By: Brenda Hunda, Curator of Invertebrate Paleontology
The layered strata that can be seen along the numerous road cuts and in streambeds in the vicinity of Cincinnati are among the most fossil rich regions in North America. As a testament to their scientific significance, these rocks are known as the North American Upper Ordovician Type Standard. To study Earth’s history 450 million years ago, the best place in North America is the famous Cincinnatian Series.
Global paleogeographic reconstruction of the Late Ordovician (450 Ma). The position of Cincinnati on the paleocontinent Laurentia is highlighted.
These outcrops of strata represent muds and limestones that were deposited over the course of millions of years on an ancient shallow tropical ocean bottom. This time in North American history looks very different from our modern perspective. North America as we know it didn’t exist, but its predecessor, Laurentia, was a southern hemisphere continent mostly covered by a warm, shallow ocean. At this time, the majority of life on Earth was in the oceans - representing most major phyla of organisms known today. Brachiopods and bryozoans comprise the greatest proportion of the biomass, but crinoids, trilobites, bivalves, corals, and gastropods are abundant and diverse. Annelids provide a rich trace fossil record, signaling the diversity of soft-bodied life within the oxygenated substrate at this time. Even though vertebrates, in the form of agnathan fish, had evolved by this time, this was definitely an invertebrate dominated world with every ecological role – from detrital feeder to predator – occupied by invertebrates.
Locality Route 3071, near Maysville KY showing most prominently the Kope Formation.
There are a variety of reasons why this region continues to be a hotbed for paleontology. The Cincinnatian Series is at the end of a pivotal evolutionary event for life on Earth. During the onset of the Ordovician period, life experienced the greatest evolutionary biodiversification event in the history of the Earth. As a result, the number of species in the oceans exploded culminating in the astounding diversity of fossils found in this region. These fossils are exquisitely preserved. Rapid burial by submarine mudflows at the bottom of the ocean provided protection from wave energy and scavengers that might otherwise destroy animal remains. The numerical abundance of fossils is also amazing. Try to pick up a rock from this region without a fossil in it – it’s hard to do!
Reconstruction of the Cincinnatian, by John Agnew, 2007.
Our incredible rocks and fossils have attracted much worldwide attention for well over 100 years. A long legacy of scientific research in American paleontology and stratigraphy was accomplished here. Cincinnati paleontology grew out of research publications from “gentlemen naturalists” that were passionate collectors and amateur scholars in the latter part of the 19th and early 20th centuries. This legacy of scientific research is still ongoing today, with the University of Cincinnati Department of Geology cited as one of the foremost paleontological programs in the country.
Isotelus maximus, the Ohio State Fossil.
Cincinnatian fossils are displayed in museums all over the world. Scientists regularly visit Cincinnati Museum Center’s research collections – one of the largest Upper Ordovician collections in the world. Whether through the legacy of major contributions to science by historical and current paleontologists, or the abundance, diversity, and preservation of organisms found in this regions outcropping strata, Cincinnati has a unique resource that continues to make significant contributions to understanding the Earth’s past.
The official City of Cincinnati fossil, Isorophus cincinnatiensis, decided by public vote at Cincinnati Museum Center and declared by the mayor of Cincinnati in 2002.
Detailed information on the Invertebrate Paleontology collections can be found at www.cincymuseum.org/research/invertebrate.