a term derived from Mount Monadnock in New Hampshire, U.S.A., to denote the " isolated remnants of hard rock which remain distinctly above their surroundings in the late stages of an erosion cycle" (T. C. Chamberlin, R. D. Salisbury). Examples are frequently found where a hard pipe of igneous rock surrounded by softer rock is gradually exposed by the washing away of the softer rock and becomes a conspicuous feature of the landscape, forming a volcanic " neck, and finally, in the later stages of erosion, a stump. The Peak Downs, Queensland, furnish many examples, and Mato Tepee, Wyoming, is a remarkably conspicuous instance of this type of formation.