This is one of the more remarkable combinations of fact and fiction in a map of the Pacific Northwest. Its source was an account published in 1708 of what was purported to be a newly discovered account of a voyage in 1640 by the Spanish Admiral, Bartholomew de Fonte. Thereafter, the account was changed and elaborated upon, most notably by this series of maps which appeared in Diderot's Encyclopedia. In its concept it promoted the hopes of a Northwest Passage and depicts the existence of a huge Mer de l'Ouest or the Sea of the West. The tracks for the Russian exploration in 1741 are traced as well as the purported track of Admiral de Fonte. This example was engraved by Heidegger of Zurich.

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Condition: B

Trimmed to neatline at binding side (left) and remargined to accommodate framing. Bit of light soil on folds.