Ferrar, H.T. 1934 The geology of the Dargaville-Rodney subdivision, Hokianga and Kaipara divisions. Wellington: Government Printer. New Zealand Geological Survey bulletin 34 86 p.
Abstract: The Dargaville-Rodney subdivision covers the south-central portion of the long North Auckland peninsula, which projects north-westward from the narrow Waitemata Isthmus near the city of Auckland. The objects of the survey were largely utilitarian, the work in effect being a stocktaking of the mineral resources of the district. Ores of copper and traces of several other metallic minerals were known to occur. Outcrops of coal at the northern end of the district and coaly partings in sandstones at Cape Rodney and near Warkworth had led to the belief that workable coal existed. More data relative to the limestone resources of the district were required, and a knowledge of the distribution of building-stone and of roadmaking materials and of the possible occurrence of clays, earths, and sands of economic value for industrial purposes was desired. Other objects of the survey were to gather data about the soils, since agriculture is the greatest source of wealth in the subdivision. (auth)