George Leslie Adkin was a self-taught scholar with the skills and integrity of a professional. Most of his working life he farmed with little profit or pleasure. His real interest was in geology and archaeology, and in the back room of his small farmhouse he worked late making meticulous records of his work.
He was born in Wellington on 26 July 1888, the first of seven children of William George Adkin, a draper, and his wife, Annie Denton. His mother's family were keen naturalists and photographers. In 1889 the Adkins secured 100 acres in the ballot for sections in the Levin village settlement, although it was some years before they settled on the land. During two years as a boarder at Wellington College in 1903–4 Leslie developed an enthusiasm for collecting plants and rocks and learned to process his own photographs. When he returned to work on the farm he began a diary that would be kept to within a month of his death: an account of farm, community and family life, and a record of his travels and scientific observations.
Adkin made many expeditions into the Tararua Range, including, in 1909, the first recorded crossing from Levin to Masterton. On these trips, and in his daily work, his imagination was fired by geological processes, and he constantly struggled to understand how the Horowhenua lowlands and the ranges had been formed. His grandfather, George Denton, had introduced him to the Wellington Philosophical Society, and he delivered a paper about the lowlands to one of its meetings in 1910. His second paper (1911) recorded his belief – in contradiction to accepted wisdom – that five high Tararua valleys had been formed by glaciation.
In 1913 Adkin took over part of his father's farm. As a special constable during the waterfront strike, he formed lasting friendships with fellow 'specials' Elsdon Best and Bernard Freyberg. Geology and tramping were curtailed during his long courtship of Elizabeth Maud Herd, an accomplished violinist, pianist and painter. Adkin's photographs depict her beauty and their life together with delicacy and passion. They married at Hastings on 14 December 1914 and had two children, Nancy and Clyde.
In 1917 criticism of Adkin's work by Charles Cotton, lecturer in geology at Victoria University College, reactivated his geological researches. He became a well-known figure at science congresses, winning some fame when he identified a geological flaw in the foundation of the Mangahao hydroelectric dam in the Tararua Range. When the sport of tramping developed in the early 1920s Adkin became the acknowledged authority on the northern Tararuas. A series of near-tragedies inspired him to join in producing a reliable tramping map and to help found the Levin–Waiopehu Tramping Club. He mapped and named mountains, led searches, and set up huts and tracks, acquiring the nick-name 'King of the Tararuas'.
A new obsession developed in 1926 when Adkin was asked to provide photographs for Te Hekenga, an account of Māori life in Horowhenua. With the help of Māori informants, he described and mapped hundreds of named Māori sites between the Manawatū and Ōtaki rivers. On Elsdon Best's advice Adkin joined the Polynesian Society, in whose journal most of his ethnological articles appeared.
Adkin created a considerable stir with Horowhenua (1948), a handsomely produced account of the region's placenames. Its most challenging feature is the interpretative essays which discuss the history of Māori occupation of New Zealand in the light of archaeology. In the dune belt Adkin had found evidence of very early inhabitants, and by calculating the rate of advance of the sandy coast concluded that they settled as early as 300–200 BC. By comparing skull measurements, adze forms and styles of ornamentation he correlated their culture with that of the moa hunter of the South Island, and with archaic carvings from Northland. He postulated that these 'Waitaha' people arrived in two migrations, first to the North and later to the South Island. The next arrivals were of the cultural type 'Ngātimāmoe', western Polynesian people influenced by Melanesian culture, who spread from a landing-place on the North Island. The North Island Waitaha moved on, amalgamating with their southern kin. Later still, the tribes of the 'Great Fleet' conquered Ngāti Māmoe, the survivors moving to the far south where they mingled with Waitaha.
In 1946, his son having taken over the farm, Adkin moved to Wellington, becoming a jack-of-all-trades at the New Zealand Geological Survey. He produced two bibliographies and further challenging papers on the geomorphology of the southern North Island.
Adkin was deeply disturbed by the threat to natural and archaeological features posed by new earth-moving technology. He had been a vice president of the Levin Native Flora Club and was an early critic of bush-felling on uplands. He was active in many organisations that heralded the rise of the conservation movement: the New Zealand Ecological Society, the Forest and Bird Protection Society of New Zealand, and the National Historic Places Trust.
Adkin made site surveys in Palliser Bay, the eastern shore of Wellington Harbour, and Wellington's west coast, developing his views on the cultural sequence. He was in great demand as a guest speaker, especially after the publication of The great harbour of Tara (1959), a treatment of the Wellington region similar to that of Horowhenua. On the councils of the Polynesian Society and of the New Zealand Archaeological Association, Adkin was a controversial figure, arguing for the amateur enthusiasts who formed the bulk of the membership. The new academic archaeologists rejected the old faith in deliberate Polynesian voyaging, the ‘Great Fleet', adze typology and Melanesian influences, and argued for a simple progression from 'Archaic' to 'Classical Māori' culture. Although under assault from cancer, Adkin was still building up evidence for a distinctive Ngātimāmoe culture when he died at Wellington on 21 May 1964. He was survived by his wife and children; his daughter died four months after her father.
As an amateur scholar, Leslie Adkin often resented academic authority, but took pains to ensure that his research was meticulously documented. In the natural sciences he linked the pioneer gentlemen amateurs to modern professionals. The Museum of New Zealand Te Papa Tongarewa houses nearly 7,000 of his negatives, his diaries and Māori artefacts; the Alexander Turnbull Library holds his albums, manuscripts, maps and drawings. He was a passionate environmentalist, seeking to understand and preserve the land and its human associations.