SAMIAN EARTH, in the materia medica, the name of two species of marl used in medicine, viz. 1. The white kind, called by the ancients collyrium samium, being astringent, and therefore good in diarrhoeas, dysenteries, and haemorrhagies; they also used it externally in inflammations of all kinds. 2. The brownish-white kind, called after samius by Dioscorides; this also stands recommended as an astringent.