Osagian (Mississippian) limestones from Alberta, Canada, contained material representing five genera of algae, three undescribed. Taxa described here include: Eolithoporella dawsoni, n. gen., n. sp. (Rhodophycophyta, Solenoporaceae); Albertaporella involuta, n. gen., n. sp. (Chlorophycophyta, Dasycladaceae); Orthiosiphon sp. (Chlorophycophyta, Codiaceae).