- GeoRef, Copyright 2004, American Geological Institute. Reference includes data from Bibliography and Index of Geology Exclusive of North America, Geological Society of America, Boulder, CO, United States
The Permian formations in the North Irwin river valley, Western Australia, were examined for their heavy mineral content. The limestone, shale, sandstone and coal measure formations comprising the Permian are 250' thick and, as an anticline, rest on an eroded basement of pre-Cambrian rocks. Zircon, garnet, tourmaline and rutile are most prevalent.