Magini's mariner's map follows Gerard Mercator's large world map of 1569 on a reduced scale, with the fanciful addition of a mountain range in the Southern Continent. The map clearly shows a northwest passage. No Great Lakes are shown and California is is not yet an Island. Interesting early projections of both North and South America, with Quivera and the Straits of Anian named, along with Florida and Norobega. Several mythical Islands, including Frieslandt and Irlant are shown. The accompanying text refers to the navigational textbooks of Pietro Nonio and inlcudes instructions to help sailors navigate from place to place.