A new stromatolite, Cliefdenia fasciculata gr. et f. nov., and an associated tube-like cyanobacterial microfossil, Girvanella? sp., are described from Late Ordovician limestones of central-western New South Wales. Typically Cliefdenia exhibits a delicate arborescent growth form, and Girvanella? sp. occurs as a prostrate and tangled meshwork of tubules in the laminae of the stromatolite. The Cliefdenia occurrences are only found in assemblages with corals (especially Tetradium cribriforme) and stromatoporoids.