The California-Baja California Collecting Sites of Edgar A. Mearns During the Second International Boundary Survey

The United States and Mexico first surveyed the international boundary between 1849 and 1855. During 1892 -- 1894, a second boundary survey was conducted to permanently mark the boundary line. A series of 258 monuments were erected to formalize the line. As part of this later boundary survey, Dr. Edgar A. Mearns organized a biological survey of the area along and near the boundary from El Paso to San Diego. The specimens collected by his survey at almost one hundred collecting sites were explicitly tied to the locations of the nearest monuments. While the biological survey was tightly referenced to the permanent boundary monuments, the actual locations of the collecting sites were only presented as a distance north or south of a given monument. Therefore, the locations did not specify a point that can be plotted accurately. This study determined coordinates for the twenty-nine collecting sites in California and Baja California Norte. The methodologies used in this paper remove most of the ambiguity associated with the locations of Mearns' sites. Biogeographers can now be more confident of the positions of these collecting sites. Future historical ecology and other biological studies involving the U.S.-Mexico boundary area will be dependent on the biological baseline provided by Mearns' survey.