Geological map of Omapere survey district [cartographic material] / compiled and drawn by R.J. Crawford.
Geological map of Bay of Islands, Russell and Whangaruru survey districts [cartographic material] / drawn by G.E. Harris ; compiled from data obtained from the Lands and Survey Department, from Admiralty charts, and from additional surveys by H.T. Ferrar and W.H. Cropp of the Geological Survey Branch of the Mines Department ; geology by H.T. Ferrar and W.H. Cropp.