The Jewel of the Twin Creek Valley
A couple months ago I went on a family visit to my wife’s hometown of Germantown, Ohio. Germantown is a quiet and picturesque town set amid the farming communities of southern Ohio, the quintessential small town, USA. I half expected to see Andy Griffith and Don Knotts in the local police car. An early settler described it as “the jewel of the Twin Creek Valley”, Twin Creek being small waterway that flows nearby. This is not a grandiose claim, since there aren’t a lot of towns on Twin Creek, but even so, it’s a nice little town.
One of the features of Twin Creek is the Germantown Dam, which doesn’t actually produce a lake but is there for flood control. The Germantown Dam is toward the eastern end of the Germantown Metropark, which encompasses old forest, hiking trails, picnic areas and, in select spots, fossil collecting. When Amber was growing up here, the dam was a well-known site for collecting fossil trilobites, shells (specifically, “curly shells”) and coral. She offered to take me out there to see what we could find.
We found first of all that fossil collecting by the dam nowadays is restricted to the south shore of the creek east of the dam. The spot is rather picked over, but we were still able to find a few good items. Amber found a very nice piece of horn coral right away, getting our hopes up, but after that we found only small brachiopods and nondescript bryozoans. After filling a small plastic baggie (there is a limit of three fossils per person per day), I brought them home, cleaned them up, and wondered what more I could learn about them.
I had picked up the book Cincinnati Fossils, edited by R. A Davis, on a previous trip to the Cincinnati Museum of Natural History & Science, and this seemed a good time to consult it. I learned that the fossils here are from the Cincinnatian Series of the Ordovician Era. The Cincinnatian Series is divided into formations: Edenian, Fairview, McMillan and Richmond; and the book has photo plates of the fossils found in each. Armed with these photos, a notepad and a glass of port, I spent an evening identifying my brachiopods as Onniella meeki and Herbertella occidentalis. This places them in the Richmond Formation, dating from 450-440 million years ago. The horn coral I identified as Grewingkia canadensis, also dating from the Richmond. I was pleased with the consistency of the result and honored it with another glass of port. I look forward to returning to the jewel of the Twin Creek Valley to do a bit of hiking and maybe collect a few more Richmondian fossils.