333 Late Ordovician to Early Silurian Solitary Rugose Corals of East-Central US

Latest Ordovician to earliest Silurian solitary rugose corals of the east-central United States - BAP #333 Four solitary rugosan assemblages are recognized within the uppermost Ordovician-lowermost Silurian sequence in the east-central United States: (1) Late Ordovician “epicontinental” assemblage (Richmondian); (2) Late Ordovician “continental margin” assemblage (Gamachian); (3) Edgewood assemblage (Gamachian-early Early Llandovery); and (4) silurian assemblage (post- Edgewood Llandovery). A Late Ordovician ‘epicontinental” Assemblage is present in the upper Maquoketa Group (Richmondian). Salvadorea randi (Elias, 1981) occurs in Southern Illionois, northwestern Illinois, and eastern Iowa. Grewingkia canadensis (Billings, 1862) has been identified in eastern Wisconsin. These species represent the Red River-Stony Mountain and Richmond solitary rugose coral provinces, respectively. They became extinct when the epicontinental sea withdrew at the end of Richmondian time, due to a major g