Timothy H. O'Sullivan 1871-1874 (survey), 1874 (expedition) 37. Lost Lakes, head of Conejos Canon, Colorado, in the Sierra San Juan range, near divide between Conejos and south fork of Alamosa Rivers, surrounded by a forest of Douglass spruce, and approximately 11,000 feet above sea-level. [Wheeler Survey, Explorations and Surveys West of the 100th Meridian]