The various discoveries of the Lower Devonian formations in western Tennessee were recounted by Dunbar in 1919.2 In 1913 Weller and Mehl announced before the Geological Society of America their remarkable find of Helderbergian and Oriskanian faunas in the limestones of Sainte Genevieve County, Missouri. This extended the known range of Oriskanian seas 500 miles, from southern Virginia to Missouri or from northern Lake Huron to Missouri. The presence of Helderbergian in Oklahoma has been known ever since J. A. Taff’s description of it in 1902 in the Tishomingo Folio of the United States Geological Survey, but far more detail was given by Reeds3 in 1911. The Oriskany, on the basis of fossils, was, however, not clearly discerned by Reeds. Then came the discovery of the true Oriskany in western Tennessee by Dunbar (Quall and Harriman formations) in 1917, extending this sea 200 miles to the southward; and now . . .