Throughout pre-European Māori history, the South Island remained an important source of stone. There was no obsidian but there was an apparent abundance of stone for adzes. The main sources were along the alpine fault and its northern and southern extensions in Southland and Nelson. Argillite for adzes was found from Rangitoto (D'Urville Island) to the mountain range lying just east of Nelson. ²¹ D'Urville Island lies in the western reaches of Cook Strait, with its northern tip almost as close to Pātea in Taranaki as it is to Nelson in inner Tasman Bay. Tribes based there, therefore, had good access to the North Island for trade; much stone went north, and east through Cook Strait, to judge from the amount of Nel- page break page 221 son argillite found in sites in the western and southern North Island. A photograph of a quarry at Samson Bay, not far from D'Urville Island and also in the Nelson mineral belt, is in chapter 5. In Southland, similar stone is available in inland and coastal localities but was only exploited on the coast; in the vicinity of Riverton and Bluff Harbour are extensive workings. ²² It appears in the same distinctive landscape as in Nelson, with hard rock protrusions lying above the general surface of the landscape. Nephrite (pounamu) was less used than argillite in the earlier periods for reasons that are not entirely clear. ²³ It is tougher than argillite, ²⁴ and was used late in pre-European history as a prestige trade good. Greenstone occurs in remote areas in geological formations similar to that of argillite, with the vegetation also stunted in the vicinity of the primary outcrops. Greenstone was also recovered from river-beds but the landscape imprint of this activity is not remarkable.