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Jack Oliver is credited with providing seismologic evidence supporting plate tectonics which encompassed and superseded continental drift with the article "Seismology and the New Global Tectonics", published in 1968, using data collected from seismologic stations, including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
One-name study the etymology, meaning and geographic origin of names, also draw on the macro perspective provided by a one-name study. Many people conducting family history, genealogical or onomastic research may conduct a one-name study of a surname in a given period or locality quite informally. A full one-name study can be daunting, particularly if the surname is very common. Conversely, a rare surname can be difficult to trace. Since such studies are usually conducted by individuals as a pastime, they are generally feasible only when a surname is not used by more than a couple of thousand contemporary people, so that