1909, Percy Dearmer, Body and soul:The doctor assists the undermind, and his assistance is often utterly indispensable: for instance, he "sets" a broken limb, and gives the undermind every assistance, ...
2010, Fons Trompenaars, Charles Hampden-Turner, Riding the Waves of Innovation:Others have named this "tortoise mind" as intuition, or the unconscious, and the id. Caxton goes on to name it the "undermind."