An important rare wall map once described as “one of the most important American maps of the period, the first to label Behring’s Straits, and the most accurate of the time in establishing more correct placements of the coasts of North and South America and Northeastern Asia.”  John Green’s map, initially published by Thomas Jefferys in 1753, was important because it provided a counter point to the controversial  Buache/Delisle map of the Pacific Northwest of 1752 and came prior to Gerhard Müller’s seminal map of the region which was published in 1754.  The controversy surrounding the Buache/Delisle map comes from the manner in which  the Northwest is depicted which suggested the probability of a Northwest passage from the pacific to the Hudson Bay based on the mythical discoveries of Admiral de Fonte in 1640. 
The three panel copy which was later published by Jefferys in his landmark The American Atlas of1775 is important in its own right in that it depicts the routes taken by such noteworthy Northern explorers as Baffin, Hudson, Bering and Tchrikow and as a result offers an excellent representation of the Pacific Northwest prior to James Cook’s famous 1778 voyage to the region in search for the NorthWest Passage. It is also important to emphasize that annotations and notes regarding discoveries in the Northwest, whether real or imagined, are written as a way to present to the viewer information on a region that was still relatively unknown. It is also of interest to note that Alaska is drawn as an island which was based on Jacob Stählin’s inaccurate depiction of the Russian discoveries of Ivan Synd.
(Sources: Hayes, D. Historical Atlas of the Pacific Northwest, Geographicus, Rumsey#4766.01)