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John François Potter (1932-2019)

Indefatigable educator, pioneer of Environmental Science and Ecclesiastical Geology who brought geology to bear on elucidating ancient churches.

John F PotterImage: John Potter points out ferruginous gravel blocks from the Taplow Gravels in the wall of St Mary’s Ripley, Surrey.  Here he found an ammonite derived from Jurassic Oxford Clay 160 million years old, that had been eroded out and redeposited 40 million years later in the Greensand Bargate Beds, and then further derived and re-deposited in Taplow Gravels by the ancestral River Wey before being quarried for building by Anglo-Saxons.  Photo: Ted Nield, 2012

Professor John François Potter, who has died aged 87 after a short illness, was born in Putney, London, where his father was a junior school teacher. The family moved to Isleworth, to a new property built on an old refuse tip in a London Clay brick pit.  Soon after, when John was seven, together with his parents and sister, he was evacuated – from Clapham Junction to Woking, which hardly left time for him to eat his sandwiches. The family were resettled at Send, where his father saw to allocating billets to all the children in his care. Unfortunately, nobody wanted an entire family, so they lived for six months in a hut by the Drill Hall, Send before eventually finding a bungalow for rent.

His father had trained as an engineer, and was offered a position at Wandsworth Tech, then based at Guildford, where he became woodwork and metalwork teacher. Moving to Guildford provided early stimulus to John’s geological interests, because they now lived on top of a chalk pit.

Early education

After the War the family returned to London with Wandsworth Tech, but preferring the Surrey countryside, John’s father accepted the deputy headship of a school in Weybridge. John was educated at Guildford Grammar’s prep school, and then Isleworth County Grammar School for Boys.  No geology was taught there, but the library did have a copy of Rutley’s Mineralogy (which he ‘took out on long term loan’).

John had a grandfather who (after delivering a steam engine there for his employers) had stayed on and mined for gold in Nannine, Western Australia – then a settlement of 40,000 but now a ghost town. Visiting his grandfather in later life, and examining his biscuit-tin of minerals, was however less inspiring to John than tales of the freewheeling outdoor lifestyle of a geologist in the colonies. John always wore a gold ring forged from a nugget which his grandfather had picked up not far from Nannine at the delightfully named ‘Flyshit Creek’. 

This family history, and the fact that geologists were in demand and well paid immediately post-war, persuaded his parents to grant John’s wish to study geology after doing Highers in Mathematics Pure & Applied, Physics and Geography. But in 1948 it was impossible to find places in university, and in any case there was National Service (NS) to be endured. John joined the Royal Engineers as ‘Surveyor – Quantity’. He was offered a one-year course at Reading, then part of London University, with the prospect of emerging as a qualified QS with the rank of Captain; but he turned it down as being insufficiently geological. As a result he did NCO training instead and came out as a Training NCO, based at Aldershot.

At the end of NS, having sent scores of trainees to their deaths in Korea and having his hearing permanently damaged by a blank round, John had saved £120. Unfortunately he admitted this to a Council official and was told that therefore he didn’t need a grant to go to Manchester University. There he studied Geology with Physics and Zoology, eventually obtaining a second class degree in Geology. The choice of Zoology as subsid subject was propitious, for it was there that he met his wife Pat to whom he was married for the rest of his life.

After graduating John took a job, in 1955, as Research Assistant at Chelsea Polytechnic where, in addition to teaching duties (instructing the young Tony Barber, Michael Audley-Charles and Peter Fookes, among others) he worked on Ludlovian and Downtonian arenaceous and rudaceous sediments in the Llandovery-Llandeilo area. This became, after five years, the subject of his PhD thesis under the (very) light supervision of Stephen H. Straw (Manchester) and William Fleet (Chelsea). It was a cause of regret to John that he never found time to publish any of this work.

West Norwood Technical College

Chelsea decided to shed its A-Level courses to West Norwood Technical College, and John was presented with the choice - either to become a Junior Lecturer at Chelsea or to migrate to West Norwood. The prospect of taking charge of something drew him to West Norwood. He also became very active in University of London Extra Mural teaching, a role that he continued to fulfil for the rest of his career, taking him abroad on many field excursions, including with George Walker to Iceland.

Soon John was teaching 36 hours per week at Norwood while still continuing to teach at Chelsea and also rushing around London for extra mural work - often taking two classes in a single evening.  Geology at Norwood developed quickly, taking on extra staff and research assistants and as much facility as could be found, providing part-time degree work, technician training courses and, when the industry began to develop, oil-industry technician courses. Technicians were more in demand then than geologists and Norwood set its sights on supplying this demand.

After three years John was placed on the full-time staff at Norwood, being made Head of Biology and Geology, expanding Biology, taking over the Tower Bridge site, adding Medical Laboratory Science, Dental Technology (John won a Maxillo-Facial Silver Award for services to Dental Technology), and Food Science Technology. Soon he was also Head of Chemistry and Vice Principal of the College. At John’s suggestion, West Norwood was renamed South London College, and they began running special 10-week courses on such topics as ‘Recent Advances in Sedimentology’, bringing in lecturers from all over the country to provide updating for fellow professionals in the medical, dental, forensic, food and geological sciences.

In the early 70s John decided to move on and became Principal of Farnborough College of Technology, the college of the Royal Aircraft Establishment (RAE) in 1975 – which by the time he retired in 1997 had shed its military connections to become the biggest Further and Higher Education establishment in the country.  

A notable change in that period was the need to convert the formerly strong Department of Physics (for which there was falling demand) into other fields – including Environmental Sciences. John, through encouragement of David Hughes-Evans of Farnborough, became an early member of the Institution of Environmental Sciences (IES) and was soon asked to be its Honorary Secretary and Editor of its journal (a post he held for 15 years). Establishing Environmental Science involved overcoming opposition from many staff members who resented the breakdown of disciplinary boundaries. Even establishing a City & Guilds Environmental Science qualification (and despite being himself on the C&G Policy Committee) proved a battle.

Ecclesiastical Geology

At this time geology – or at least research – had long taken a back seat, though he had continued to lecture in the subject, partly for what he termed ‘relaxation’. Then, at Farnborough, he was lecturing on gravels when someone at the British Geological Survey (then the ‘Institute of Geological Sciences’) phoned to ask him about a church in Ripley, Surrey because “we don’t know what it’s made of”.

John was familiar with the ferruginously cemented gravels used in the older churches of Surrey, and in this case a newly opened gravel pit lay right alongside, exposing an iron pan “about ten feet down”. This showed John that the builders had used what was immediately available under the site – in this case, a pliable ferruginous gravel that quickly became hard once exposed to the air.

On re-examining the church he found a piece of gravel that contained an Oxford Clay ammonite, and he reasoned that it had come secondarily from the Bargate Beds (L. Greensand), down the River Taplow and into the Taplow Gravels (see picture and caption). One church led to another. John eventually visited all the churches of Surrey during rare days off. Eventually this work covered the entire Thames Basin, and led him to conclude that these gravels were widely used by Anglo-Saxon builders. A few papers and articles followed, but this was his first step into using churches as outcrops, and conversely, using geology to help interpret the history of their construction.

After leaving Farnborough, Surrey University made John Emeritus Professor, and asked if he would like to head up the Nursing Degree course (a course Farnborough had also bid to establish, but had lost to Surrey). Surrey had brought many nurses onto their teaching staff, but few had publications.  Many were doing research, but in small isolated groups. Surrey were worried about the Research Assessment Exercise, and how these excellent but otherwise relatively research-unproductive staff could become better established academically through better coordination. Not best pleased to be landed yet another administrative role, John nevertheless took up the offer.

The Surrey job being part-time, to fill the other days of his week, John offered his services to Reading University as Emeritus Research Professor.  Reading supported him in his geological work in exchange for ‘the odd lecture’ and, of course, the credit of his subsequent publications. Those publications consisted first of work, initiated around 1975, on rocks in relation to churches in the Thames Valley and the way they were employed by their builders; and second, work (with a  Research Assistant) on the churches of the Romney Marsh area. 

Here it became clear that early post-Roman masons –referred to under the catch-all of ‘Anglo-Saxon’ – worked with rocks in a unique fashion (‘patterned work’ as John called it, including such features as alternating ‘long and short’ work at the quoins), and that these styles were also seen in areas where available rocks had no dominant bedding or foliation to dictate them.

Work with the mathematician, architectural historian and Anglo-Saxon building specialist Harold McCarter Taylor (1907-1995, Vice-Chancellor, Keele University, 1961-67) followed.  Taylor, whose two-volume work on pre-Norman ecclesiastical architecture is an acknowledged classic, and who had catalogued all the then-known ‘Anglo-Saxon’ church fabrics in England, told John (after a single day in the field) that he had always wanted a geologist to work with ‘because I thought there was much more in the rocks than I realised’.

Once again, John discovered resistance to those who transgressed disciplinary boundaries, finding that some archaeologists did not welcome being told that walls they had designated 13th Century on the basis of window openings, were, at their bases, perhaps three hundred or more years older.  Controversially, John was subsequently able to extend the geographical coverage of ‘patterned work’ beyond England into Scotland, Wales and Ireland and the Isle of Man, helping to increase the number of churches known to possess pre-Romanesque elements, and showing that this distinctive pattern of building was not confined to ‘Anglo Saxons’ at all.

John was a long-term Fellow of the Society (elected 1955), once even (unsuccessfully) applying for Council, and writing for Geoscientist.  He also suggested to Elspeth Matthews that she establish the Society research fund now named for her. John’s affiliation with the Geologists’ Association was if anything much closer, because of his enthusiasm for the amateur wing and for extra mural education in general. 

The decline in extra mural university education - and in interest in geology among the young - were a source of great sadness. “When I was young, the money was good, the world was your oyster and there were plenty of jobs and it attracted plenty of people. We were training geologists for the world, including the States.” He also regretted the replacement of the coherent syllabus with a unit course ‘cafeteria system’ in universities, which he felt led to over-specialism and lack of coordination. He blamed the Open University for this.

“I made my greatest impact in helping to establish Environmental Science as a subject”, he told me; “and there can’t be many people who have worked 50 years in the same department – the Extra Mural Department of London University! I wrote, asking them for my gold watch. I never got one!”


John Potter, a self-professed ‘expansionist’ in education, changed the lives of tens of thousands of people; wrote papers and articles on everything from dental implants to space travel; was an indefatigable booster for geology; gave himself fully to amateur and student alike, and was pivotal both in Environmental Science, and latterly, Ecclesiastical Geology. His greatest publications indeed are the many mighty monographs published in the last decades of his life, by the British Archaeological Record (BAR). These establish beyond doubt the importance of geology to understanding pre-Romanesque masonry. The final volume was submitted to BAR shortly before his death. 

He will be sorely missed by all who had the good fortune to know him during his long, varied and industrious life.

John François Potter, born 6 July 1932; died 27 November 2019.

By Ted Nield

  • Quotations from an interview with John Potter conducted by Ted Nield as part of the Geological Society Oral History Project in 2010 and lodged in the Society Archives.