This map is the first in a series of four that represents one of the most important exploring efforts of the American Southwest. It shows the topography and geology of the lower Colorado River in four panels (each about 8.5" x 14"), beginning at the Gulf and ending in Black Canon at Fortification Rock. It is fully and finely engraved and provides a great amount of information. Wheat says this is one of the best maps engraved by the remarkable F.W. von Egloffstein. It was engraved using his system that imparts the appearance of depth to the topography that resembles an aerial photograph.

References: Wheat (TMW) #947.

Condition: B

Toned along fold lines, else very good.