Born in Mung, Charente-Maritime, France, on 19 July 1900. After earning her baccalaureate at the age of 17, she studied literature in England and submitted a thesis in 1931 on “the influence of Diderot’s biological ideas on his literary oeuvre". In 1932, she met the Abbé Breuil and helped him classify the prehistoric art collections of the Muséum d’histoire naturelle in Bordeaux. She then specialised in prehistory. He invited her and Dorothy Garrod to study caves in Palestine. She also met Germaine (Minne) Henri-Martin and took part in the excavations at Quina (Charente), and then at Fontéchevade. After visiting La Marche cave in Lussac-les-Châteaux with Abbé Breuil, she resumed her research on the Roc-aux-Sorciers site in 1946 in partnership with Garrod. They discovered the rock sculptures together. Following the death of Garrod in 1968, Saint-Mathurin continued to analyse the findings of their excavations. In the late 1960s, Saint-Mathurin was appointed project manager at the Musée d’archéologie nationale. In 1976, she donated a selection of sculpted, engraved and painted blocks from the collapsed ceiling of the deposit to the museum. The blocks have remained in the museum’s collection to this day. She died in 28 August 1991 and bequeathed the deposit to the French State and her complete collection and archives to the Musée d’Archéologie nationale.