Two gastropod steinkerns from the Lime Creek formation of Iowa

I found two gastropod steinkerns in my collection of Lime Creek Formation fossils from Rockford fossil Park in Iowa. They caught my attention as I was sorting the fossils I have from there to find duplicates I could send to a friend in Germany.

The first specimen is a Bellerophon sp. steinkern. Gastropods of this genera generally have a wide flaring opening to the body chamber and the shell whorls imbricate (directly overlap) upon themselves. The flared portion of the shell is missing on this steinkern but the whorls are imbricated.

Anterior view

Left side profile

Posterior view

Dorsal view

Ventral view

The other steinkern specimen is a gastropod called Floydia sp. whose whorls are not imbricated but appear stacked on top of each other. As this is an internal steinkern it is impossible to tell if the genera is correct much less determine the species.

Left profile

Anterior view

Dorsal view

Ventral view

Both of these specimens come form the late Devonian aged Lime Creek formation (Fransian stage).

Cyrtina brachiopod from Iowa

These are the last of the fossils that I have from the Devonian of Iowa. They are a couple of Cyrtina specimens with some strange growth patterns.I think they both come from the Lime Creek formation (Devonian, Givetian).

Specimen #1
Brachial valve

Anterior

Pedicle valve (note the odd curving of the shell)

Posterior

profile

Specimen #2

Anterior

Pedicle valve (note the "twisted" look in the tip of the shell)

Posterior

Profile

I think both of these specimens came from Nathan so thank you!

Paracyclas from Iowa

The only pelecypod that I have from the Lime Creek formation of Iowa is this Paracyclas that my friend Nathan gave me. It's not terribly detailed but you can still make out what it is.

Thanks to Nathan for this specimen!

Pachyphyllum woodmani from Iowa

I was excited when my friend Nathan gave me this piece of Pachyphyllum woodmani from the Lime Creek Formation near Rockford, Iowa. It's a favorite coral of mine and I've been wanting one for a while. Pachyphyllum is a colonial rugose coral that is different from other rugose corals in that it does not build walls to protect and support it's body. Instead the calyx (cup) is everted (a structure turned from the inside out) into a shallow cup within which can be found the expected septa but they are also present outside of this cup. I'm still looking for more information on this group of fossil corals but this is somewhat typical of the family Phillipastreidae.

Specimen #1

Side Profile

Underside showing growth pattern and epithecal surface

Specimen #2

Side profile

Thanks to Nathan for giving me fossils.

Cyrtospirifer whitneyi brachiopod from Iowa

A brachiopod that is well known from the upper Devonian is Cyrtospirifer. Below is a specimen of Cyrtospirifer whitneyi from the Lime Creek formation of Iowa (Devonian, Fransian stage).

Brachial valve

Anterior

Pedicle valve

Posterior

Profile

Several specimens together to show size difference between specimens.

I've found specimens of Cyrtospirifer in the rocks of the Lock Haven formation(PA)/Wiscoy formation(NY) but only as external shell molds in fossil shell hash.

Schizophoria iowaensis brachiopod from Iowa

Schizophoria appears to be a long lived genus with Paleodb.org listing occurances from the Silurian through the Carboniferous. The specimen below is Schizophoria iowaensis from the Lime Creek formation of Iowa (Devonian, Fransian stage).

Brachial valve

Anterior

Pedicle valve

Posterior

Profile

It's overall shape reminds me of a Rhipidomella sp. except that Schizophoria has a much more convex brachial valve.

Tenticospirifer brachiopod from Iowa

Tenticospirifer is a triangular shaped brachiopod that reminds me of Cyrtina a lot. These specimens came from the Lime Creek formation (Devonian, Fransian stage) near Rockford, Iowa. The planar shape of the posterior indicates that these brachs likely lay flat on the seafloor or other surface and just flopped the brachial valve open to feed.

Specimen #1

Brachial valve

Anterior

Pedicle valve

Posterior

Profile

Specimen #2

Brachial valve

Anterior

Pedicle valve

Posterior

Profile

I purchased these specimens from an auction on E-bay.