So I was doing some research on Calceola, a strange genus of Devonian aged coral that has a lid, or operculum, and came across some new information that I'd not read before. Here is a good reference picture of Calceola from This Site
I'd known that these odd ball corals (that are closer to Rugose coral than Tabulate) are common from the Devonian in parts of Europe and Morocco but had never heard of them being found here in the US. As I looked through links and .pdf files I was surprised to find a reference from an 1885 Kentucky text. Click here It's a book that was published in 1885 by the Kentucky Geological Survey called "Kentucky Fossil Corals - A Monograph of the Fossil Corals of the Silurian and Devonain Rocks of Kentucky" by William J. Davis. On plate 131 are pictures of a reference specimen of Calceola sandalina along with other specimens that had been recovered from the "White Clay of Niagara" near Louisville. While all the specimens on the page are attributed be Calceola, some look like other types of rugose corals and, without examining the original specimens, I can't be sure of what they are but most do bear a resemblance to the aforementioned coral. It must be extremely rare, although I did read somewhere that they are occasionally found in Tennessee too.
The specimens that I have in my collection come from the Devonian of Morocco. Here is a large example that is missing it's lid (not uncommon).
And this specimen still has the lid in place:
This fossil has the septae lines preserved along the walls of the coral.
The other bit of info was a paper that discussed the Ontogenetic development (The origin and development of an individual organism from embryo to adult) of Calceola. As I was reading through I learned that Calceola was one of the last genera from a line of these "lidded corals" that extended to Cambrian time through to the middle Fransian stage of the upper Devonian. It also conjectured that the individual animals lived with the flat side of the coral on the surface of the sea floor rather than being upright like a Rugose coral. It has some good illustrations of the life habit of the animal (see image below) as well as passing reference to other species of these corals.
Another publication Middle Devonian Calceola sandalina (Linnaeus, 1771) (Anthozoa, Rugosa) from Moravia (Czech Republic): aspects of functional morphology, gerontic growth patterns and epibionts. provided the following image of the life position of Calceola:
This reference from Steinkern.de has some good pics of specimens and a little info about the genera from Germany (although it's in German and so you will want to translate it with Babelfish or another translating service.)
Stolarski, J. 1993. Ontogenetic development and functional morphology in the early growth-stages of Calceola sandalina (Linnaeus, 1771). Courier Forschungs-Institut Senckenberg 164: 169-177.
Galle, A. and F. Ficner (2004). Middle Devonian Calceola sandalina (Linnaeus, 1771) (Anthozoa, Rugosa) from Moravia (Czech Republic): aspects of functional morphology, gerontic growth patterns and epibionts. Geodiversitas, 26(1).