Reserves of plastic clay are less than previously estimated, based on recent workings and drilling. Ridge of Adelaidean shale is expected to be suitable for brick manufacture.

Since 1947 the area has been a major source of construction sand, brick shale and plastic clay, the latter two commodities being produced from fluvio-lacustrine sediments of Tertiary age within the Golden Grove Embayment, on the eastern flank of the...