Walking over dinosaurs. A forgotten tale of buried treasure .
Updated: Mar 21
The two high points of my geography lessons at Bletchley Grammar School were the eccentricity of the teacher, who in violation of all health and safety considerations spent many hours smoking in his book cupboard, and my pleasure in drawing geological maps. I can’t say that I understood much of what I was copying but at least I could make colourful patterns without being disturbed or having my ignorance exposed- I also got heady on the smell of the felt tip pens!
I am sure that if I had then known about the connection between my dull school work and the dinosaur excrement industry that had once thrived nearby- just two miles away at Great Brickhill- my interest would have been further aroused.
Brick making, functioning and historical, was all around us and school trips to observe the manufacturing process, were not uncommon but I never once heard a word whilst growing up, about the proximity of the coprolite mines. Those short-lived engines of the industrial and agrarian revolutions in Victorian England are now hardly remembered.
It is only very recently that I have discovered that there was ever such an industry in the first place and that I had spent a large chunk of my life either near, or on defunct workings, or intersecting with its legacy in ways to which I was oblivious.
As a child, I played in the woods in the Brickhills, and 30 years later, as a parish priest, I was a regular visitor to a Nursing Home called Pirton Hall, which unknown to me at the time had been built on the profits of the coprolite industry.
I have also since realised that a walk I took long ago from the nearby village of Pirton, in Hertfordshire, to Cambridge took me through, and above, much of the golden strata of the coprolite bearing Mesozoic clays, to the city which has some claim to having launched the short-lived industrial boom in the first place.
I wonder if the Extinction Rebellion protestors who in February dug up parts of Trinity College lawn realised that the college had made a fortune out of an earlier fossil industry and that Cambridge itself stands upon the last great unexploited coprolite bed?
Coprolite was a term coined by Revd William Buckland in 1829 from the Greek, coprus meaning dung and lithos, stone. Sadly, very little of it was actually produced by terrestrial dinosaurs. Most of it came from marine reptiles such as ichthyosaurs and plesiosaurs, although in some places it was overlaid by a Pleistocene layer, where it was augmented by mammoths, hyena, sharks teeth and the occasional whale’s ear bone. Buckland is celebrated for finding the first Megalosaurus and having a full house when it came to eccentricities; as soon as he realised that the rounded stones often found near to or inside the skeletons of extinct sea creatures were pieces of fossilised faeces, he had a table made from the novel substance to amuse his guests in his college rooms in Oxford.
It was 1845 before another Reverend scientist stepped in and promoted the use of the material as a fertiliser. John Stevens Henslow is best known for his role in the career of Charles Darwin, for it was he who recommended his young student to Captain Fitzroy, as a suitable ‘gentleman’ naturalist companion on the voyage of the Beagle. But being a professor of Botany in Cambridge he was someone who people listened to, so when he advocated coprolite’s commercial usefulness at a British Association for the Advancement of Science in that year he provided publicity for, and impetus to a recent manufacturing development, and a scientific justification for its effectiveness.
It had long been known that bone meal was good for crops, and efforts to find a suitable supply had in the past led to such desperate measures as the looting of battlefields and catacombs and even the deployment of mummified cats! The fossils of the Red Crag in Suffolk near Felixstowe had been dug out and ground up to be used as fertiliser since the 1820s.
In 1827, Humboldt brought back to Europe tales of the beneficial effects of ‘guano’, huge deposits of which were to be found on the Chincha Islands off Peru, on crop growth. Shortly afterwards quantities of these potent cormorant droppings were sent to England for chemical analysis and it was discovered that it was the phosphate present in high concentrations that encouraged plants to thrive. Henslow drew attention to the higher phosphate concentrations found embedded within the clay literally underfoot. A supply which would also be cheaper and less vulnerable to political instability than guano.
The narrow belt, just a few miles wide, of phosphatic nodules is found mainly in Cretaceous clays running from Norfolk to Oxfordshire, with a few outlying seams in Yorkshire and Kent. The origins of the industrial process are not totally clear. The first person to think of adding sulphuric acid to bone meal to better release the phosphorous appears to have been John Murray who pioneered the method in Dublin in 1817, but by the middle of the 1840’s the process was being applied to fossil rocks; by John Bennett Lawes in England and Justus von Liebig in Germany.
Adding sulphuric acid to the phosphate nodules created more soluble ‘ super- phosphates’ which were much more readily absorbed by growing plants.
It is no surprise that a process involving fossilised dung and sulphur generated an appalling odour, the main gas by-product being hydrogen sulphide, so Lawes first factory which had opened Deptford, quickly closed down and he moved the operation to a site on the river Orwell at Bramford, on the outskirts of Ipswich.
The coprolite boom began around 1850 and had begun to peter out by the middle of the 1880s but in those years, it had a significant impact on the economy, particularly in Buckinghamshire, Bedfordshire and Cambridgeshire, much of which has gone unnoticed. The main reason for its invisibility is that it left behind no scars on the landscape. Because the layer of coprolite bearing clay was so near to the surface, and barely 3 feet thick, once holes had been dug to extract it, usually by hand, the fields from which it was taken could easily be restored. The mining team then just moved on to the next patch.
The economic and social effects of the industry were broad. Nationally- in 1874 Coprolite exports were worth more than tin exports- and locally, in the areas of maximum exploitation within a radius of 30 miles of Cambridge, where populations were reliant so much on agriculture. As the rest of the rural economy was floundering here there is abundant evidence of higher wages, population growth, and cultural vitality.
Coprolite miners were paid £3 per week, compared to the £2 that went to farm labourers. Workers were consequently drawn to the area- half of the villages in Cambridgeshire saw a leap in population during the coprolite years and all were within four miles of a mining operation. Barton Le Clay School, in Bedfordshire, expanded from a pupil roll of 74 to 300 by 1878. A school in Duxford was built with proceeds known to be from the local coprolite diggings.
Grand houses which had land to lease out for prospecting became grander, and Methodist chapels and congregationalist churches sprung up at the height of the boom. And, of course, other institutions with large landholdings, like Trinity College in Cambridge, made extensive profits.
The famous fertiliser brand Fisons was built on coprolite.
The decline of the industry was as rapid as its rise, and it set in after 1885, by which time all the easily accessible reserves had been exploited and abundant alternative sources had been located as far afield as New Jersey, Spain and South Africa. There was one final but subdued flourish during World War One when coprolite was turned to in desperation as a native source of phosphorous for munitions.
Rupert Brooke’s poem, The Old Vicarage, Grantchester, written in Berlin 1912, might stand as a perfect testament to cultural amnesia. It mentions a number of villages that were fossil mining centres just a few decades before but wreathes them in drowsy classical nostalgia. There is no hint of what miners wrestled from the ground under the
‘ Meads towards Haslingfield and Coton…’
And it is perfectly likely that the church clock itself, which was installed at a cost of £100 in 1870, at the precise moment that coprolite profits were flowing into the village’s coffers, was a legacy of the trade.
It was able to symbolise stability and tradition by standing at ‘ ten to three’ because of a forgotten industry and long-dead marine reptiles lost in deep geological time.
• Ian Tattum is a priest in the Church of England who writes occasional pieces about the people who shaped the history of science and human and animal travel-real and fictional