mountains and hills in South Australia, extending 100 miles (160 km) east-west across the northern part of Eyre Peninsula, south of Lake Gairdner; they rise in the west as high as 1,550 feet (475 metres) at Mount Bluff. The ranges were first sighted by the English explorer Edward John Eyre in 1839 and named in honour of the colony's governor, George Gawler. The semiarid shrub vegetation that covers them allows only limited livestock raising, but the eastern sector, known as the Middleback Ranges, contains rich iron ore deposits, mined since the early part of the 20th century. The region includes Yantanabie Historic Reserve, site of an old Aboriginal quarry, and Yardea National Estate, site of picturesque columns of porphyry.