The reason for this misguided placement appears linked to both a pervasively optimistic belief that such a passage would be found and a misleading report that appeared in a German tract printed circa 1508 in Augsburg, the Copia der Newen Zeitung auss Presillg Landt (New Tidings out of the Land of Brazil):
“Learn also that on the twelfth day of the month of October, a ship from Brazil has come here, owing to its being short of provisions. The vessel had been equipped by Nono and Christopher de Haro, in partnership with others.
Two of those ships were intended to explore and describe the country of Brazil, with the permission of the King of Portugal. In fact, they have given a description of an extent of coasts, from six to seven hundred leagues [1800 to 2100 miles], concerning which nothing was known before.
They reached the Cape of Good Hope, which is a point extending into the ocean, very similar to, Nort Assril, and one degree still further. When they had attained the altitude of the fortieth degree, they found Brazil had a point extending into the sea. They have sailed around that point, and ascertained that the country lay, as in the south of Europe, entirely from east to west. It is as if one crossed the Strait of Gibraltar to go east in ranging the coast of Barbary.
After they had navigated for nearly sixty leagues [180 miles] to round the Cape, they again sighted the continent on the other side, and steered towards the northwest. But a storm prevented them from making any headway. Driven away by the Tramontane, or north wind, they retraced their course, and returned to the country of Brazil.”
The tract relates the account of a Portuguese sponsored expedition, which explored over 1800 miles of previously unexplored Brazilian coastline—Brazil being the name then applied to the whole of South America. We can deduce from the numbers provided that the exploration of new coastline began some 1,620 to 1,920 miles north of the 40th parallel, somewhere in the range of Sao Paulo and Rio de Janeiro, Brazil. The continuation of the sailors’ route is plotted out onto both Schöner's 1515 interpretation of the South American continent as well as a modern map of South America in Figure 5. Schöner’s 16th century rendering of the South American coastline approximates the modern rendering as well as would be expected from a map of the time, but as soon as we pass beyond the 40th parallel we begin to see where Schöner's interpretation strays radically.