 Prior to the mid 1920 's , travelling north from Geraldton necessitated going through <unk> , Dairy Creek and Gascoyne Junction . In 1926 , a direct route joining Geraldton and Carnarvon was constructed , shortening the trip by 160 km ( 100 mi ) . At first , this was little more than a rough bush track , at least partly used for extracting sandalwood . As there was often little water along this route , tanks with catchment roofs were built at eight locations along the track . The tanks were named for their distance from Carnarvon , at 40 , 55 , 85 , 110 , 125 , 150 , 180 , 200 miles . These tanks provided a life @-@ saving function but when the road was later sealed , they became less important and were gradually removed except for Number 8 tank . Number 8 tank is still used by travellers and marks a point 100 mi ( 200 km ) from Geraldton , 200 mi ( 300 km ) from Carnarvon . 
