Inspection of 57 pits of 82 sites revealed that most pits are located on stranded coastal dunes of Pleistocene Bridgewater Formation. Material has also been won from interdunal lagoonal dolomite of Padthaway Formation. These materials are limited to the western area. To the east, Pleistocene sediments do not significantly onlap the uplifted Pinnaroo Block. Here Pliocene sands overlain by Holocene Molineaux Sand are unsuitable for road rubble thus severely limiting options. Only 5 pits are located in the Parilla and Loxton Sands. 38 alternative potential sources are nominated for further testing.