David Mills died at Moreton Morrell, Warwickshire, on the 31st of August, 2000, at the age of 67. He was born at Church Stretton, Shropshire, and attended Shrewsbury School before studying geology at the University of Nottingham. On graduating in 1957, he joined the Geological Survey and was assigned to work in north-east England. There he began a long association with geological maps and with their practical applications.

His first geological mapping was in the valley of the River Irthing, in the north-eastern corner of the Bewcastle Geological Sheet (12). Soon, as an alternative to losing him to National Service, the Survey transferred him to work of more immediate economic significance in the Durham Coalfield (Sheet 32, Barnard Castle). When this work was completed, he was transferred once more, to the newly formed North Wales Unit where he contributed to the Denbigh and Rhyl sheets.

For a brief period, 1965-1966, he was seconded to the Ministry of Technology, at their regional office in Leeds. Following this, he was back in north-east England to carry out, from existing mapping and borehole records, the desk compilation of the Wolsingham (26) and Richmond (41) sheets. During a significant part of the 1970s, David was attached to the geological and site investigation studies being carried out by Babtie, Shaw & Morton prior to and during the construction of the water-carrying tunnels linking the Tyne, Wear and Tees valleys. He also was part of the Geological Survey team that remapped the Newcastle-upon-Tyne District (20).

It was during this latter period that David's great talent as a map compiler and editor was recognized by his management. Thus, in the early 1980s, he joined the Marine Geology Group as editor of the Offshore Geology 1:250 000 map series. This series, of over 300 maps, was the culmination of a major BGS and Department of Energy study of the UK Continental Shelf extending over two decades. From this time onwards, to his retirement, hundreds of geological maps crossed David's desk. His task was to ensure that the maps were produced to a common standard and that these offshore productions were prepared to the same high standards as the Geological Survey's traditional land maps. He was involved in all stages of map production, from the early draft stages through to the drawing office and final printing. This task took considerable managerial and diplomatic skills. It was almost invariably done with a smile on his face, though there were occasions when his anger would erupt if a map was late or not up to what he judged was the required standard. Many a discussion was held in his smoke-filled room to resolve a problem on the new nomenclature for the offshore Quaternary succession, the style of the sea-bed sediment maps or other such issues. By the time of David's retirement from BGS in July 1990, most of the offshore maps were completed. The production of this series on schedule owed much to his own individual efforts, to his willingness to accept responsibility, and to his ability to manipulate and cajole both senior and junior BGS staff to see the job through.

During his time working on offshore maps, he never entirely forgot his land-based roots. Thus, seeing that there were difficulties in the compilation of the Newcastle-upon-Tyne 1:50 000 Geological Sheet, he persuaded management to add this to his already extensive duties. Nor was he finished on retirement. He had had, for a long time, an ambition to prepare a memoir for the Newcastle District. Many thought that this would not be possible given that the mapping team had long since scattered with variable documentary records retained. David persuaded management otherwise, and the wisdom of that can be judged from the memoir written and published during his retirement. A similar ambition to write a memoir for the Wolsingham District was left unfulfilled at his death. In his final years, he embarked on a new career as a part-time lecturer in geology at the Department of Adult Education of Warwick University.

David was more interested in the practical application of geology than in academic research. He was a pioneer, at the 'grass-roots' level, in the conversion of the Geological Survey from an 'old style' public service body into the present-day more commercially orientated organization. He was not a prolific publisher, his principal publications, with a few notable exceptions, are to be found in around half a dozen Geological Survey 1:50 000 geological maps and sheet memoirs. His geological legacy, however, is much greater than this would immediately suggest. For example, the value to the nation of the Offshore Geology 1:250 000 map series is immense and probably incalculable, having a significant bearing on both the exploration and exploitation of valuable economic resources, most particularly oil and gas. David's crucial role in their preparation will be his lasting memorial.

David joined the Yorkshire Geological Society in 1958, and always took a great interest in the affairs of the Society. Many will remember his years of service on Council, during which time he was Assistant Secretary (1967) and General Secretary (1968-1970).