its adoption by the First Pan African Congress in 1947, the Three-Stage Chronology was amended by the Third Congress in 1955 to include a First Intermediate Period between Early and Middle, to encompass the Fauresmith and Sangoan technologies, and the Second Intermediate Period between Middle and Later, to encompass the Magosian technology and others. The chronologic basis for definition was entirely relative. With the arrival of scientific means of finding an absolute chronology, the two intermediates turned out to be will-of-the-wisps. They were in fact Middle and Lower Paleolithic. Fauresmith is now considered to be a facies of Acheulean, while Sangoan is a facies of Lupemban. Magosian is "an artificial mix of two different periods". Once seriously questioned, the intermediates did not wait for the next Pan African Congress two years hence, but were officially rejected in 1965 (again on an advisory basis) by Burg Wartenstein Conference #29, Systematic Investigation of the African Later Tertiary and Quaternary, a conference in anthropology held by the Wenner-Gren Foundation, at Burg Wartenstein Castle, which it then owned in Austria, attended by the same scholars that attended the Pan African Congress, including Louis Leakey and Mary Leakey, who was delivering a pilot presentation of her typological analysis of Early Stone Age tools, to be included in her 1971 contribution to Olduvai Gorge, "Excavations in Beds I and II, 1960–1963." However, although the intermediate periods were gone, the search for the transitions continued. Chronology In 1859 Jens Jacob Worsaae first proposed a division of the Stone Age into older and younger parts based on his work with Danish kitchen middens that began in 1851. In the subsequent decades this simple distinction developed into the archaeological periods of today. The major subdivisions of the Three-age Stone Age cross two epoch boundaries on the geologic time scale: The geologic Pliocene–Pleistocene boundary (highly glaciated climate) The Paleolithic period of archaeology The geologic Pleistocene–Holocene boundary (modern climate) Mesolithic or Epipaleolithic period of archaeology Neolithic period of archaeology The succession of these phases varies enormously from one region (and culture) to another. Three-age chronology The Paleolithic or Palaeolithic (from Greek: παλαιός, palaios, "old"; and λίθος, lithos, "stone" lit. "old stone", coined by archaeologist John Lubbock and published in 1865) is the earliest division of the Stone Age. It covers the greatest portion of humanity's time (roughly 99% of "human technological history", where "human" and "humanity" are interpreted to mean the