West Virginia: fossil coral (state gem)
West Virginia: fossil coral (state gem)
West Virginia does not have a state fossil, but it does have a fossil for its state gem, the fossil coral Lithostrotionella. This coral and many other varieties lived about 340 million years ago, during the Mississippian Period, at a time when the state was encroached on by a shallow sea. In addition to corals, this sea hosted a teeming fauna of brachiopods, trilobites, and fish.
The two main types of Paleozoic corals were tabulate and rugose corals. Lithostrotionella is a tabulate coral. Both types were decimated in the great extinction at the end of the Permian Period, 245 million years ago, which wiped out over 90% of the species of life on earth. They were subsequently replaced by the scleractinian corals which form our reefs today.
Corals may look like plants, but they are really animals. The familiar part of a coral is a colony's calcium carbonate skeleton; in each small recess lives an individual coral animal called a polyp. These polyps strain small particles of food from the water with their tentacles, and retreat into the safety of the skeleton when threatened. Additionally, the polyps host symbiotic algae called zooxanthellae within their tissues, which are nourished by the coral's waste products and in turn provide additional food via photosynthesis. These algae give the corals various colors when they are alive. In fossil form, it is impurities within the minerals that impart various hues. Many West Virginia coral reefs have been replaced by chalcedony, a variety of microcrystalline quartz.
Lithostrotionella is found almost exclusively in the Hillsdale Limestone of Greenbrier and Pocahontas counties in the southeastern portion of the state. It became the state gem with the passage of House Concurrent Resolution No. 39 on March 10, 1990.
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