Alexander Henry Green was born in Maidstone in 1832, the son of Rev T S Green, a classical scholar and headmaster of Ashby-de-la Zouch Grammar School.
Whilst still at school his knowledge of Ashby was so good that that when Andrew Ramsay visited the area for the British Geological Survey, he acknowledged Green as the local authority and suggested he should join the Survey.
He went to Cambridge in 1855 and was appointed a Fellow at Gonville and Caius College in the same year.
Joining the Geological Survey in 1862 as an assistant geologist, Green spent some time in Buckinghamshire and Derbyshire before he was transferred to the Yorkshire and Derbyshire coalfields and promoted to geologist in 1867.
His time at the Survey was relatively short, only covering 13 years, but his output was considerable. He was involved in mapping a large number of sheets at one and six inch to the mile scales and producing the memoirs for Banbury, Stockport, Tadcaster, Dewsbury, Barnsley and north Derbyshire.
However, he was probably best known for his substantial contribution to the understanding of the geology of the coalfields and for the 800 page Geology of the Yorkshire Coalfields, the largest and most important coalfield memoir published by the Survey. Green became regarded as one of the leading authorities on the geology of coal.
His fieldwork was accurate and meticulous and his sketches are works of art. The 1973 disaster at the Lofthouse colliery in Wakefield could possibly have been averted if the relevant information held in one of Green's notebooks and on his field map had been seen and understood.
He resigned from the Survey in 1874 and took up the professorship of geology (and professorship of mathematics) at the new Yorkshire College in Leeds. There he produced his textbook, the popular Manual of Physical Geology. As well as being a Senior Fellow of Caius College Cambridge, he was also a lecturer at the Royal School of Military Engineering in Chatham.
In 1888, at the age of 75, Professor Prestwich retired as professor of geology at Oxford and Green willing accepted the post, teaching and reorganising the collections and doing consulting. He was a Fellow and vice president of the Geological Society of London and appointed a Fellow of the Royal Society in 1886. He served on the council of the Royal Society from 1894–95.
He studied parts of the Lake District and Donegal and was an early convert to the 'heresy' that the surface of the ground owes its form mainly to the actions of rain and rivers. As an expert on coal and water supply, Green also visited Newfoundland and South Africa, the results of which were considered major contributions to the subject.
Unfortunately he never recovered fully from a bout of severe influenza in 1895 and died in 1896 at the relatively young age of 64.
The National Geological Repository at BGS holds 13 of Green's beautiful field sketches in pencil, ink and watercolour.