Gasport Member of Lockport Fm.
Collection of Foote

Reef sudivided in 
Initial reef facies with delicate branching corals (Halysites, Cladopora) and branching bryozoans (Hallopora). Encrusters Girvanella, trepostome bryozoans and tabulate coral Alveolites.
Reef core facies with umrella-shaped asymmetrically shaped stromatopores and a few favositids.
Reef flank facies with debris of stromatopores, tabulate corals and others.
Reef thicknesses in area: 3-12 m.
Reefs less diverse than Niagaran reefs of Michigan.
Example for reef succession in Walker and Alberstadt (1975).