The ultramafic rocks of Queensland show similarity in field relationships, tectonics, petrology, and chemistry with those of New South Wales and probably belong to one belt. They comprise three groups, namely, massive serpentinites, schistose serpentinites, and composite rocks, characterized by a schistose matrix with inclusions of the massive variety. It is suggested that two phases of ultramafic activity occurred along the fracture system where the rocks are found, possibly in both the middle Devonian and lower Carboniferous periods. The serpentinite breccias, formation of antigorite, and the problem of genesis are discussed.