Spur

1940

Related works

United States Geological Survey, 1935

United States Geological Survey, 1935

United States Geological Survey, 1936

United States Geological Survey, 1937

United States Geological Survey, 1935

United States Geological Survey, 1936

United States Geological Survey, 1936

United States Geological Survey, 1935

United States Geological Survey, 1935

United States Geological Survey, 1935

United States Geological Survey, 1937

United States Geological Survey, 1937