Address before the Rocky Mountain Medical Association, June 6, 1877 : containing some observations on the geological age of the world, the appearance of animal life upon the globe, the antiquity of man, and the archaeological remains of extinct races found on the American continent, with views of the origin and practice of medicine among uncivilized races, more especially the North American Indians : To which is appended a synopsis of the previous addresses and also biographies of the members of the association