Cryptostome Bryooa from the standard Blackriveran and Trentonian (Middle Ordovician) include species of the escharoporid, pachydictyid, and stictoporid groups. Six genera, 12 species, and 6 subspecies, including 4 subspecies of Pachydictya acuta, are described here. One genus (Championodictya)), 2 species and 4 subspecies are new. Overlapping ranges of these species appear useful for stratigraphic correlation. On the west side of the Adirondacks, distributions suggest that several species migrated from NW to SE with time (late Blackriveran-middle Trentonian). Phylogenetic relations of 12 escharoporid genera suggest evolution from Chazyodictya lineage. --V.M.J

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