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Author Citation: Craigin 1893

This is a Cretaceous oyster that I found in Post Oak Creek in Sherman, Texas. The oyster has traces of a yellowish calcite-cemented sandstone found in the upper part of the Arcadia Park Formation of the Eagle Ford Group.

“Pediformis” in the name, Ostrea alifera var. pediformis, means foot-shaped or pediform because the oyster looks like a foot or boot.

In “The Lower Cretaceous Gryphaeas of the Texas Region”, Bulletin of the US Geological Survey #151, 1898, author Robert Thomas Hill eliminated the Ostrea alifera Cragin, and Ostrea alifera var. pediformis Cragin names because he considered them to be Ostrea lugubris Conrad. I disagree with Hill’s decision because my oyster is larger than most O. lugubris (now Cameleolopha lugubris) and lacks an attachment scar characteristic of O. lugubris. My oyster may be a genus Cameleolopha since both Cameleolopha bellaplicata and Cameleolopha lugubris occur nearby. Unless new information can be found, my oyster should be called: Ostrea alifera variety pediformis Craigin.

For more information and drawings of Ostrea alifera and Ostrea alifera variety pediformis Craigin see:

Cragin, F. W., “A Contribution to the Invertebrate Paleontology of the Texas Cretaceous”, Austin, Texas, B.C. Jones & Co., State printers, 1893.