 The concept that the continents once formed a contiguous land mass was first proposed by Alfred Wegener, the originator of the scientific theory of continental drift, in his 1912 publication "The Origin of Continents" ("Die Entstehung der Kontinente").He expanded upon his hypothesis in his 1915 book "The Origin of Continents and Oceans" ("Die Entstehung der Kontinente und Ozeane"), in which he postulated that, before breaking up and drifting to their present locations, all the continents had formed a single supercontinent that he called the ""Urkontinent"".The name "Pangea" occurs in the 1920 edition of "Die Entstehung der Kontinente und Ozeane", but only once, when Wegener refers to the ancient supercontinent as "the Pangaea of the Carboniferous".