The sea cliffs at Joggins, Nova Scotia, are the most extensive and continuous Carboniferous section in eastern North America. Although the section has been considered to have formed within a nonmarine depositional basin, paleobiological information indicates that parts of the section were deposited in brackish water. The occurrence of a trace-fossil assemblage, which includes Cochlichnus, Kouphichnium, and Treptichnus, is part of an assemblage of biogenic structures that apparently reflects paleodeposition within fluvial systems that may have experienced distal marine influences. Presence of agglutinated foraminifera characteristic of brackish-water environments supports this interpretation. This information provides new evidence of brackish-water conditions at Joggins such as those now being widely recognized in other Carboniferous coal-bearing sections.