Marie Stopes, The Discovery of Pteridosperms And The Origin of Carboniferous Coal Balls

Marie Stopes (1880-1958) is chiefly remembered as a birth control pioneer and sexologist, but in her twenties and thirties she carved out a highly successful career as a palaeobotanist and coal geologist. This paper outlines her early geological research on coal balls—carbonate concretions found within the Carboniferous coal seams of northern England, which preserve the remains of the peat-forming plants in beautiful anatomical detail. Stopes worked on coal balls during three intervals of her career. In the first phase (early 1903), she was Francis Oliver's postgraduate research assistant at University College London, during the critical period leading up to the ‘discovery of pteridosperms’ with D. H. Scott. Stopes's role was to hunt down key specimens in coal ball collections scattered across Britain. In the second phase (late 1904-1907), which followed a year of doctoral research in Munich, she grappled with the more broad-ranging questions of the origin of coal balls, their stratigraphic distribution, and the taphonomy and ecology of the plants they contained. This work took place while she was a Demonstrator in Botany at the Victoria University of Manchester, and was undertaken in collaboration with David Watson. Their findings transformed understanding of coal ball origins and remain influential today. In the third phase (1907-1911), she searched for coal balls in other countries and other stratigraphic intervals. She explored Japan for coal balls of Mesozoic age (1907-early 1909), and although unsuccessful in this particular endeavour, later she became one of the first geologists to locate Carboniferous coal balls in North America in 1911.