Mapped by Captain Randolph B. Marcy, in charge of the U.S. Army detail guarding citizens bound for California gold rush. Captain Marcy exploded theory that West Texas was a desert. In making his map, he traveled along a chain of springs and lakes known to Comanche guide Manuel. In October 1849, reached The Big Spring-a site marked by many converging Indian trails. From here he went northeast, toward the Red River. Trail was later used by many emigrants, and was followed by a transcontinental railroad and stagecoach line.