Humanity Is Flushing Away One of Life’s Essential Elements
In a field of sugar beets outside Cambridge, England, Simon Kelly stands above a narrow trench gouged into the rusty earth, roughly 15 feet deep and 30 feet long. “Welcome to the pit,” says Kelly, a bespectacled, white-bearded geologist in a straw hat and khaki shirt. “You’re seeing something that hasn’t been seen in a long time.”
The rock layers exposed in the trench date back more than 100 million years, to when England lay submerged beneath a warm, shallow sea. Kelly—a researcher at a nonprofit geology consultancy—specializes in marine fossils of that era (“Dicranodonta vagans!” he exclaims when I find a stone pocked with the impressions of tiny clam-like shells, which he asks to keep). That’s why he had an excavator dig this trench in 2015, and why he has spent countless hours since then sifting through its trove of treasures. “Going out to Simon’s hole, are you?” Kelly’s wife deadpanned when I picked him up on the morning of my visit.
I had come because “Simon’s hole” also contained objects of more recent historical significance: dull, round pebbles that once helped feed the United Kingdom. By the 1800s, centuries of cultivation had sapped Britain’s soils of nutrients, including phosphorus—an essential element for crops. At the time, manure and bones were common sources of phosphorus, and when the country exhausted its domestic reserves, it looked elsewhere for more.
“Great Britain is like a ghoul, searching the continents,” wrote Justus von Liebig, the German chemist who first identified the critical role of phosphorus in agriculture. “Already in her eagerness for bones, she has turned up the battlefields of Leipzig, of Waterloo, and of the Crimea; already from the catacombs of Sicily she has carried away the skeletons of many successive generations.”
Then, in the 1840s, geologists discovered phosphorus-rich stones buried in the fields around Cambridge—the same smooth, coffee-colored rocks welded into the walls of Kelly’s trench. “This is what they were after,” he says, pointing to a layer of bean-to-buckeye-size lumps.
These nodules were initially believed to be fossilized feces, and became known as coprolites, meaning “dung stones.” Most turned out to be chunks of mineralized sediments, but that did not diminish their utility as fertilizer.
“In the remains of an extinct animal world, England is to find the means of increasing her wealth in agricultural produce,” Liebig wrote. “May her excellent population be thus redeemed from poverty and misery!” And it was.
Over the ensuing decades, workers extracted 2 million tons of coprolites, transforming the fields and fens of southeast England into a warren of pits and trenches that dwarfed Simon’s hole.
