One of the many benefits of posting a “Fossil of the Week” is that I learn a lot while researching the highlighted specimens. I not only learn new things, I learn that some things I thought I knew must be, shall we say, updated. The above slab contains dozens of brachiopods (and a few crinoid ossicles and bryozoans). I have long called the common brachiopod here Onniella meeki. Now I learn from my colleagues Alycia Stigall and Steve Holland at their great Cincinnatian websites that since 2012 I should be referring to this species as Cincinnetina meeki (Miller, 1875). Jisuo Jin sorted out its taxonomy in a Palaeontology article three years ago:
Species: Cincinnetina meeki (Miller, 1875)
This slab, which resides in our Geology 200 teaching collection, was found at the famous Caesar Creek locality in southern Ohio. It is from the Waynesville/Bull Fork Formation and Richmondian (Late Ordovician) in age.
You may see some bryozoans in this closer view. This bed is a typical storm deposit in the Cincinnatian Group. The shells were tossed about, most landing in current-stable conditions, and finer sediments were mostly washed away, leaving this skeletal lag.
Jin, J. 2012. Cincinnetina, a new Late Ordovician dalmanellid brachiopod from the Cincinnati type area, USA: implications for the evolution and palaeogeography of the epicontinental fauna of Laurentia. Palaeontology 55: 205–228.