Fine‐grained and coarsely oolitic kaolinite clayrocks that closely resemble in composition, texture, and structure those of the Garie Formation in the southern part of the Sydney Basin are described from the Western Blue Mountains of New South Wales. The kaolinite clayrocks form part of a fine‐grained unit, here designated the Docker Head Claystone Member. It is concluded that the kaolinite clayrocks are the equivalent of the Garie Formation and represent fluviatile accumulations of detritus derived from the same highly weathered source rocks that gave rise to the Garie Formation.