floor and extends from Baryulgil, to Nymboida. The conglomerate often appears as a cliff. The Corindi Conglomerate is a local name for a hailstone sized gravel near Corindi. The Mill Creek Siltstone. are often olive green or yellow-brown with bright red joint planes. The Marburg Subgroup extends for along the western side of the basin into Queensland from Corindi. It is mostly clay cemented cross bedded quartz sandstone, but this is interbedded with claystone and shale. At the base is the Blaxland Fossil Wood Conglomerate Member at Blaxlands Creek. The fossil wood is in the form of horizontal tree trunks up to long and in diameter. The fossilization process replaced the wood with limonite and hematite. The Towallum Basalt is a thick layer near Nymboida, Glenreagh and Moleton trig station overlying the Marburg formation. The Walloon Coal Measures forms a U shape around the east, south and west sides of the basin. It consists of claystone, shale, siltstone, arenites, and coal seams and the plant fossils in it show a Jurassic age. The next layer of rocks in the basin forming a nested U shape in its exposure is the Kangaroo Creek Sandstone. This sandstone has saccharoidal texture, and glistens white and cream. This is not due to angular sand grains, but results from silica crystallization. It is up to thick. The Grafton Formation is the sedimentary unit in the core of the basin. It is the youngest of the beds being between Late Jurassic and Early Cretaceous. It occurs from Grafton to Casino consisting of soft sandstone, siltstone and claystone. Dolerite has intruded this at Glenugie Peak, and near Banyabba. Rifting along the east coast of Australia commenced and uplifted the eastern side of the Clarence Moreton Basin. This resulted in the splitting off of the Lord Howe Rise and the opening of the ocean floor. References External links Northern Rivers Geology Blog - Clarence Moreton Basin Sedimentary basins of Australia Mesozoic rifts and grabens Geology of New South Wales Geology of Queensland