Published online by Cambridge University Press: 14 July 2015
Acidolites Lang, Smith and Thomas occurs in upper Middle and Upper Ordovician, Lower and lower Middle Silurian rocks of Ontario and Quebec. On Anticosti Island, Quebec, the genus is represented by A. tenuis (Billings) in the Upper Ordovician (Gamachian) Ellis Bay Formation; the new species A. arctatus, A. compactus and A. helianthus in the Ordovician–Silurian boundary beds at the top of the Ellis Bay Formation; the new species A. arctatus, A. compactus and A. lindströmi in the lower Llandoverian Becscie Formation; A. arctatus in the mid-Llandoverian Gun River Formation; and an unnamed species in the upper Llandoverian Jupiter Formation. The lower Llandoverian Clemville Formation of the Gaspé Peninsula, Quebec, contains Protaraea clemvillensis Parks, now considered to be Acidolites. The upper Middle to lower Upper Ordovician Cobourg Formation near Ottawa, Ontario, contains A. cf. arctatus, formerly included in Protaraea vetusta (Hall). The lower Wenlockian Amabel Formation in southern Ontario contains a species of Acidolites as yet unnamed.