Cincinnatian Fossils from the Ordovician

Cincinnatian Fossils

From The Ordovician Period

A Guide to the Ordovician Fossils of Southeast Indiana Collected by Jeff Bryant


Arthropoda Cnidaria
Arthropoda Cnidaria Brachiopoda Molluska Echinodermata Bryozoa Hemichordata

Ordovician fossils from southeast Indiana

The typical Ordovician
landscape of SE Indiana and SW Ohio

All fossils were obtained (unless otherwise stated) from a roadcut approximately two miles north of I-74 in Indiana on State Highway 1, just south of Brookville. CLICK HERE (298 KB) to see a birdseye view of the exposed area. The exposed rocks are from the Arnheim, Waynesville, Liberty, and Lower Whitewater formations. All formations and the included fossils were laid down during the Ordovician period, about 450 million years ago or so and are part of what is known as the Cincinnatian Arch. This Arch is due to a fold in the rock layers that allowed the younger rock layers near the crest of the arch to be eroded and for the older Ordovician rocks to be exposed.

To see a typical view of the exposed material from this site up close, CLICK HERE (388 KB).

Identification of specimens was done with the aid of Cincinnati Fossils:An Elementary Guide to the Ordovician Rocks and Fossils of the Cincinnati, Ohio, Region. Ed. R.A. Davis. Cincinnati Museum of Natural History. 1985.

I have done my best to identify the fossils presented here correctly, but nobody is perfect, and I am not a professional. I encourage anyone to contact me ( if they believe I have misidentified any of the specimens. I will do my best to correct any errors.

The icons at the top of the pages represent most of the phyla found at the location mentioned in the paragraph above. A few examples came from other locations and are so noted.