Thomas Brunner carried out the most arduous exploring expedition in the history of New Zealand. He was a member of the Nelson survey staff, and he had made several reconnaissances of the South Nelson and West Coast country before his great journey of 1846–48. With Charles Heaphy and William Fox (afterwards Sir William Fox), both of whom were in the service of the New Zealand Company at page 26 the Nelson settlement, he explored, in February, 1846, much of the country about Lakes Rotoroa and Rotoiti, and the headwaters of the Buller River, and with Heaphy he made, later on in that year, the first path-finding tour down the West Coast as far as Arahura. On that journey the explorers, with their Maoris used some of the bush ladders made for climbing the precipices on the rugged Coast by a war-party which had gone down the Coast some years previously. Heaphy and Brunner named many features of the country as they went, and mapped the region traversed. At Arahura and Taramakau they found the Maoris working pounamu or greenstone in the ancient manner, shaping and polishing meres and pendants, and Heaphy placed on record a description of the methods used.