Reed, J.J.; Grant-Taylor, T.L. 1966 Geological investigations of quarries and potential quarries for road metal production, Wellington area. Lower Hutt: New Zealand Geological Survey. Report NZGS 5 18 p.
Abstract: At the request of the Ministry of Works, a geological examination of quarries and potential quarries in the Wellington region was made early in May. All the quarries in the 1961 Mines Statement list were visited, as well as one representative Hutt River shingle plant that of River Shingle and Sand (1935) Ltd. Several presently-abandoned quarries were also visited and an assessment made of potential areas. The area covered extends from Wainuiomata to Paraparaumu, including Wellington City. The most significant geological feature of the Wellington district is that for practical purposes only one rock unit is involved - alternating bands of indurated sandstone and mudstone that are generally known as greywacke and argillite respectively. The geological conditions are such that there can be rapid changes in the proportion of argillite to greywacke, and in the amount of shearing and fracturing. Uniformity of product is generally only available by selective quarrying. River shingle from the Hutt River is the major supplier of high-grade building aggregate and sealing chips, but this must alter as supplies dwindle in the next decade. The problem of suitable rock is not so much a geological problem as one of rock selection, supervision, quarry management and economics. (auth/ARC)