Measures 14.5 x 19" . Copper engraved sheet relating to the center of western mapping, Mt. Diablo, the western starting point of the township and range grid established in 1848 to map the expanding United States of America. Exempt from these boundaries are the California Rancho Lands established prior to 1848 and confirmed by the US Federal courts in the 1850's through the 1880's. Tis issue tanned and trimmed and priced accordingly