Current paleogeographic reconstructions extend Late Ordovician Taconic-derived siliciclastics across the central Canadian craton prior to the terminal Ordovician glacioeustatic lowstand. Revision of the Late Ordovician Dawson Point Formation of the Timiskaming outlier greatly reduces the distribution of these siliciclastics, and documents a greater spread of shallow-water carbonate of Richmondian age. As revised, the Dawson Point Formation contains two informal members: a deep-water graptolitic shale that grades upward into shallow-water siliciclastic redbeds, and an upper member of shallow-water, muddy, crinoidal limestone with interbedded shale, likely representing low-energy shoals on a muddy shelf. Deep-water shale accumulation began in the upper manitoulinensis graptolite Zone following foundering of the regional foreland carbonate platform.