347 Latest Ordovician to Early Silurian Colonial Corals of East-Central US

Latest Ordovician to earliest Silurian colonial corals of the East-Central United States - BAP #347 A distinctive assemblage of colonial corals occurs in uppermost Ordovician (Gamachian) to lowermost Silurian (Lower Rhuddanian) strata within the east-central United States. This Edgewood Assemblage is strikingly different from Late Ordovician assemblage that preceded it in other parts of the North American cratonic interior, and differs from the Silurian assemblage that succeeded it. The Edgewood Assemblage existed during an important time of global environmental change and mass extinction. Some of the taxa have an Ordovician character; these include the youngest North American tetradiid, which is among the last representatives of an important Ordovician order. Other taxa represent first appearance of typically Silurian forms: the oldest definite plasmophorid, the earliest North American Halysites, and the first pyconostylid. Our study analyzes this significant assemblage in terms of