“Old maps are filled with inaccuraciesórivers running a wrong course, cities placed incorrectly, coastlines lacking bays, and mountains, lakes and islands missing completely. The mistakes in old maps are one of the primary aspects which makes them interesting to us, and much of the history of cartography is the history of the correction of these errors. One category of cartographic error consists of what are called ëgeographic myths.í These are geographic features that appear on the map but not on the earth…” (Thanks The Map Room!)
Link:
http://www.philaprintshop.com/myth.html
