The discovery of gold at Sutter's Mill set off the California gold rush of 1849. In this scene prospectors dig for gold with picks and shovels and pan for the precious metal. In the center three well-dressed men, possibly Sutter and two friends, carefully examine the contents of a prospector's pan.
The frieze in the Rotunda of the United States Capitol contains a painted panorama depicting significant events in American history. Thomas U. Walter's 1859 cross-section drawing of the new dome (constructed 1855-1863) shows a recessed belt atop the Rotunda walls with relief sculpture. Eventually it was painted in true fresco, a difficult and exacting technique in which the pigments are applied directly onto wet plaster. As the plaster cures the colors become part of the wall. Consequently, each section of plaster must be painted the day it is laid. The frieze is painted in grisaille, a monochrome of whites and browns that resembles sculpture. It measures 8 feet 4 inches in height and approximately 300 feet in circumference. It starts 58 feet above the floor.
The frieze is the work of three artists, Constantino Brumidi, Filippo Costaggini and Allyn Cox. It was designed by Brumidi, an Italian artist who studied in Rome before emigrating to America. Brumidi created a sketch for the Rotunda frieze in 1859 but was not authorized to begin work until 1877.