A great pair of geological maps that were published in the monumental and important railroad surveys of the 1850's. The first map of the entire state of California has delicate hand coloring applied to reflect geological knowledge. The nine geological types are color-coded per the legend at left according to the surveys of Lieut. R.S. Williamson of the Topographical Engineers. The map contains interesting details throughout, and especially along the American River. Lake Tahoe is not shown, rather in its place is a small lake named Lake Bonpland. A huge Mono Lake is depicted. In Southern California, Los Angeles, San Gabriel, San Pedro, and more are located. Prepared to accompany the report of William P. Blake, Geologist of the Expedition. Lithographed by Sarony, Major & Knapp of New York. 1853. (16 x 22.2")
The second map's title continues "…Along the Route explored by Lieut. John G. Parke, Corps of Topl. Engrs. Prepared to accompany the Report of Thomas Antisell M. D. Geologist of the Expedition." (11.5 x 16.8") This beautifully hand colored map details the coast and coastal mountain range between the two cities. Names Point Conception, Santa Barbara, the Bay of Monterey, and the major rivers in the region and extends eastward to include the Kern Lakes. The legend at lower left identifies eight geological formations with a color key.

References: 1) Marcou & Marcou #678.

Condition: A

Both folding, as issued. The former with a couple small spots, the latter with a hint of fold toning, still very good.