In 1860 Carleton Watkins made his first sustained sequence of landscape views, forty-eight mammoth-plate photographs of the Las Mariposas estate. Located less than forty miles from Yosemite, Las Mariposas featured a landscape of little topographical interest–but beneath the surface of this 40,000-acre estate lay the southern end of California's Mother Lode, the world's richest gold vein. John C. Frémont, who owned the land, and his associates used Watkins's images of mills, dams, and roads at the Las Mariposas estate when trying to raise funds for mining from investors.
A wagon road and a parallel railroad rising two thousand vertical feet from the Merced River led to the economic heart of the Las Mariposas property, the Pine Tree and Josephine Mines. In this view looking north from Mount Josephine, the railroad tracks and the line traced by the river nearly meet near the picture's center, neatly bisecting the rocky terrain.