Cotton was then director of the Coromandel School of Mines from 1908 to 1909, and geology lecturer at
Victoria University College from 1909 to 1920, when he was appointed to the newly created chair of geology. He retired in 1953, and that year was awarded the
Queen Elizabeth II Coronation Medal. In the
1959 Queen's Birthday Honours, Cotton was appointed a
Knight Commander of the Order of the British Empire. According to Cotton himself an important development to his scientific career was the introduction of
air mail to New Zealand allowing letters to arrive or be received from Europe within two weeks. Cotton was a leading New Zealand scientist, and became an international authority on geomorphology through the publication of his books and papers, the most notable of which include
Geomorphology of New Zealand (1922),
Landscape (1941),
Geomorphology (1942),
Climatic Accidents in Landscape Making (1942),
Volcanoes as Landscape Forms (1944),
The Earth Beneath (1945),
Living on a Planet (1945), and
New Zealand Geomorphology (1955). Cotton's work became the inspiration for much of
Colin McCahon's
landscape painting. ==Legacy==