Setting apart her achievements in the promotion and use of birth control, Marie Stopes was a recognised expert in palaeobotany, the study of ancient fossilised flora.
While doing fieldwork in Brora, Sutherland in 1907, she discovered an important and as yet unrecognised Middle Jurassic fossilised plant. Her paper on the subject was noted by the Royal Society, who sponsored her research in Japan.
While there, she produced a number of scholarly scientific articles on fossilised plants. An example of this is her 90 page long paper on cretaceous plants, published in the Philosophical Transactions of the Royal Society.
On her return, she visited New Brunswick in Canada at the invitation of the Canadian Government, and published a comprehensive monograph on the flora of that region.
An expert too in the constitution of coal, she prepared a monograph in 1918 for the Department of Scientific and Industrial Research, a study which was valuable economically as well as scientifically.