Stromatoporoids from the Devonian (Eifelian to Lowest Frasnian) of Manitoba, Canada

Abstract

Twenty-two taxa of stromatoporoids are described from the outcrop belt of the Elm Point, Winnipegosis, Dawson Bay, and Souris River Formations in Manitoba. The Elm Point Formation contains a fauna of stromatoporellids of Eifelian age that is characterized by the new species,Stromatoporella manitobaensis.The Winnipegosis stromatoporoids are dolomitized but the widespread speciesActinostroma tyrrelli, Taleastroma logansportenseand the new speciesTrupetostroma imbrexcan be recognized in this Givetian assemblage. The Dawson Bay fauna is characterized by the appearance of the dendroid forms,StachyodesandDendrostromaand species ofHermatostroma, Trupetostroma, andParallelopora.A species ofActinostroma, comparable toA. filitextumis the most abundant stromatoporoid in the Dawson Bay Formation. The Souris River fauna, referred to as theArctostroma contextumassemblage, is widespread at the Givetian-Frasnian boundary. Elements occur elsewhere in western Canada in the Beaverhill Lake, Waterways, lower Duperow and lower Fairholme units. Stromatoporoids in these four assemblages are relatively restricted in their stratigraphic occurrence and sufficiently widespread in their distribution to be useful in correlation.