Continental drift Permian era but failing to account for glaciation in India, Australia and South Africa. Geophysicist Jack Oliver is credited with providing seismologic evidence supporting plate tectonics which encompassed and superseded continental drift with the article "Seismology and the New Global Tectonics", published in 1968, using data collected from seismologic stations, including those he set up in the South Pacific. It is now known that there are two kinds of crust: continental crust and oceanic crust. Continental crust is inherently lighter and its composition is different from oceanic crust, but both kinds reside above a much deeper "plastic" mantle. Oceanic crust
Association for the Study of Classical African Civilizations derives its membership from African Americans across class and occupational locations. The organization has since expanded into an international organization, with membership regions representing the continental United States, as well as the Caribbean, Africa, and Europe. ASCAC has four commissions which advance this agenda: education, research, spiritual development, and creative production. Along with creating study groups throughout the world, ASCAC holds an annual conference, operates a youth enrichment program, and is editing a comprehensive history of Africa. The Association for the Study of Classical African Civilizations was initially conceptualized and developed during the First Annual Ancient Egyptian Studies Conference in