During the month of December, the ground is usually covered with layers of snow here in Michigan (USA). Fossil exploring is put on hold till Spring, but 2012/13, so far, has shown a mild winter. As a result, the sand along the shores of Lake Michigan is more exposed to strong winds which has actually assisted fossil finding ventures. The moving sands reveal hidden treasures one must partake while it lasts.
Below, are two recent discoveries of favosite corals found on Oval Beach in SW Michigan. Favosite is an extinct genus of “tabulate” coral characterized by a honeycomb pattern of cells which housed the jelly-like coral polyp creatures. The “tabulae” refers to the horizontal internal partitions visible from the side view of a good specimen. The partitions are abandon cells which reveal the growth patterns of the coral.
The Petosky Stone sample “Hexagonaria, percarinata” is about the size of a fist. It’s rather smoothed out from water and sand action, yet it’s a nice large specimen that reveals the entire coral. From the side view, you can clearly see how it was attached to the seafloor by its stem.
The other favosite coral I found is often referred to as a Charlevoix Stone. It’s smaller in total size, as well as its polygon patterns. It clearly also belongs to the Hexagonaria genera, meaning six sided for its polygon shaped chambers. Both these coral stones are nicknamed after quaint shoreline Michigan cities located near each other in the NW region of the lower peninsula. Yet, both favosite cousins can be found from the far northern to the far southern shores of the Great Lake along the Michigan coast.