Clams, Oysters, and Scallops - Hood Co., TX

Kingdom: Animalia, Phylum: Mollusca, Class: Bivalvia, Order: Ostreoida, Families: Pectinidae (scallops, pectens), Inoceramidae (clams), Gryphaeidae (oysters)

There is a layer or formation consisting of oyster fossils at the base of Comanche Peak on our property. These fossils are commonly called Devils Toenails, are from the Gryphaeidae family, and are a genus of extinct oysters. In addition, there are many Ceratostreon texanum, an oyster with a shell about 3 inches long. On our property this layer is from the Cretaceous period, and represent oysters that lived in the shallow sea waters of what is now the Gulf of Mexico about 90 million years ago. We have found complete specimens as shown below, and both the articulated valves, and the 'lids' of the oysters. Their shells are very thick, and grow in bands. The oyster beds are very prominent, with large areas of oysters making up a layer several inches thick. In the same area are Neithia (scallop) shells, and clams from very small to the size of the palm of your hand. At higher elevations on Comanche Peak, we have found deer heart clams, as well as rudists. 

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Hood County, TX