Biostratigraphy and taxonomy of Drumian (middle Cambrian) agnostid trilobites of the Manuels River Formation, Avalonian Newfoundland, Canada

New, accurately located and well-preserved agnostid trilobite material has been collected from the type locality of Drumian (middle Cambrian, Miaolingian) Manuels River Formation, Newfoundland, Canada. The well-exposed grey to black shales containing fauna were deposited on former microcontinent Avalonia. Four interval zones for succession are proposed, namely, Tomagnostus fissus, Hypagnostus parvifrons, Ptychagnostus atavus punctuosus zones. fissus distinct each other, which leads a significantly shorter stratigraphically higher Zone compared with other sections (Scandinavia, South China, Utah Nevada, Greenland). Specimens atavus, however, occur abundantly, 107 specimens identified in short succession. can be correlated globally. faunal assemblage is comparable that Scandinavia, Greenland England. affinis recorded first time 1408 assigned suborders Agnostina Eodiscina families Peronopsidae Ptychagnostidae, Condylopygidae Eodiscidae, respectively, following species: Peronopsis fallax (Linnarsson), scutalis (Hicks), parvifrons (Angelin), (Brøgger), (Tullberg), (Lundgren), perrugatus (Grönwall), Pleuroctenium granulatum (Barrande) Eodiscus punctatus (Salter).