Wooster’s Fossils of the Week: a little sclerobiont community (Upper Ordovician of Indiana)

Last week the students of my Invertebrate Paleontology class found many excellent fossils in the Whitewater and Liberty Formations of southeastern Indiana. We will be featuring some of them in this space. I want to start with one of my own finds: an orthid brachiopod from the Whitewater known as Vinlandostrophia acutilirata (Conrad, 1842), the inside of which is encrusted by old friends Cuffeyella arachnoidea (Hall, 1847) and Cornulites flexuosus (Hall 1847).

A sclerobiont is an organism living in or on a hard substrate. The branching form in the image is Cuffeyella arachnoidea, an encrusting cyclostome bryozoan well represented in the Cincinnatian Group (Taylor and Wilson, 1996). The conical encrusters are the lophophorate Cornulites flexuosus, a species we covered earlier in detail.

These sclerobionts were well protected from weathering on the outcrop by the concavity of the brachiopod’s interior, giving us a beautiful vignette of an ancient ecosystem.


Conrad, T.A. 1842. Observations on the Silurian and Devonian Systems of the United States, with descriptions of new organic remains. Journal of the Academy of Natural Sciences of Philadelphia 8: 228-280.

Hall, J. 1847. Paleontology of New York, v. 1: Albany, State of New York, 338 p.

Taylor, P.D. and Wilson, M.A. 1996. Cuffeyella, a new bryozoan genus from the Late Ordovician of North America, and its bearing on the origin of the post-Paleozoic cyclostomates, p. 351-360. In: Gordon, D.P., A.M. Smith and J.A. Grant-Mackie (eds.), Bryozoans in Space and Time. Proceedings of the 10th International Bryozoology Conference, Wellington, New Zealand, 1995. National Institute of Water & Atmospheric Research Ltd, Wellington, 442 pages.

About Mark Wilson

Mark Wilson is a Professor of Geology at The College of Wooster. He specializes in invertebrate paleontology, carbonate sedimentology, and stratigraphy. He also is an expert on pseudoscience, especially creationism.
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4 Responses to Wooster’s Fossils of the Week: a little sclerobiont community (Upper Ordovician of Indiana)

  1. Sarah says:

    Hello Mark,For supposedly havnig a B.S., you sure don’t understand much about the scientific method. Evolution is still a e2€œTheorye2€9d, which by its own definition is NOT fact. Yep, just like the theory of gravity, germ theory, the kinetic theory of gas, cell theory, atomic theory, plate tectonic theory, quantum theory, and many, many others. Just like evolution, these are still theories’. Also, like evolution, these are well supported theories. Many of which are incomplete and contain discrepancies. Yet we still accept these other well supported theories as fact’. In the strict sense, yes, none of these are proven to be strictly facts, only our best working models. But the common use of the word fact’ does apply to well supported scientific theories, including evolution. The Bible has never been proven wrong I hear this claim from Christians quite frequently. The problem is that Christians often have a warped sense of proof’. They ultimately rely on the Bible as the final arbiter of truth. Of course the Bible cannot be proven false when you start with that sort of circular reasoning. The problem is that circular reasoning is not valid logic.I could list a bunch of things that the Bible is wrong about, but I’m sure you’ve heard them all before and have circumlocuted your way around them.

  2. Mark Wilson says:

    I’ve left this comment here because I can’t figure out if this “Sarah” is a real person or a robot with a Facebook page. The comment makes no sense, at least not in this context. Why, though, would a spammer send us to a Facebook page?

  3. charles oldham says:


    Thank you for your site, from time to time I find it very helpful in my research on the upper ordovician. i am in the process of writing a detailed report on the Liberty Formation. i am a retried geologist work worked in Kentucky for 30 years, now I get to do my own thing.


  4. Mark Wilson says:

    Thanks for the comment, Charlie. I love doing these entries. It’s nice you commented on the same post as the bizarre “Sarah”! Many more Ordovician entries are on their way! Cheers, Mark

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