Continent Europe and Asia together as a single continent, dubbed "Eurasia". In this model, the world is divided into six continents, with North America and South America considered separate continents. Geologists use the term "continent" in a different manner from geographers. In geology a continent is defined by continental crust: a platform of metamorphic and igneous rock, largely of granitic composition. Some geologists restrict the term 'continent' to portions of the crust built around stable Precambrian "shield", typically 1.5 to 3.8 billion years old, called a craton. The craton itself is an accretionary complex of ancient mobile belts (mountain belts) from
A Map of Middle-earth A Map of Middle-earth A Map of Middle-earth is the name of two colour posters by different artists, published in the late 1960s and early 1970s by the American and British publishers of J. R. R. Tolkien's book "The Lord of the Rings". Both posters were based on cartography by J. R. R. Tolkien and Christopher Tolkien to depict the fictional region of Middle-earth. None of these maps cover the whole continent of Middle-earth; instead they only portray the north-western part of the continent, where the story of "The Lord of the Rings" takes place. The earlier poster, signed "BRem"