I first came across the word ‘marl’ when i was reading one of the Inspector Dalgliesh novels by P.D.James. P.D.James, Baroness James of Holland park, actually went to the same school as I did – although a couple of generations before me!! I can’t now remember which novel, maybe it was ‘Unnatural Causes’, but a body was found in a flooded marl pit; no doubt there was an explanation as to what marl is in the novel but I only had a vague memory of it being some sort of clay and had assumed, wrongly, it was used in the brick making industry.
Marl pits appear in the book I am writing at the moment, provisionally called ‘The Lost House’, or maybe ‘The Last House’ and so I did some research into marl and discovered that it was indeed clay, but it was used as a sort of soil conditioner on farms to ‘sweeten’ the land.
Marl is apparently a natural mixture of clay and carbonate of lime, or secondary calcium carbonate, used as a fertilizer for hundreds of years, since the time of the Norman Conquest, before ‘modern’ farming technology replaced it, using crop rotation, using specific crops which enrich the soil and spreading with lime. Even today you can go past fields which have been limed, looking like unseasonable snow.
Marl pits are the pits which have now filled with water and provide often valuable habitats for wild life… I’ve been to gravel pits which have become nature reserves, but I have never been to a marl pit… I think as part of my research I should find one and visit, armed with my camera of course!