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Jack Oliver is credited with providing seismologic evidence supporting plate tectonics which encompassed and superseded continental drift with the article "Seismology and the New Global Tectonics", published in 1968, using data collected from seismologic stations, including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
The Defence of Duffer's Drift a lightly armoured small group of "Redeemers" against attack from a larger force, that would not tie down many "Redeemer" troops un-necessarily. The Defence of Duffer's Drift The Defence of Duffer's Drift is a short 1904 book by Major General Sir Ernest Dunlop Swinton. It purports to be a series of six dreams by "Lieutenant Backsight Forethought" about the defence of a river crossing in the Boer War. The infantry tactics in the early dreams are disastrous, but each time BF learns something until in the final defence he is successful. "The Defence of Duffer's Drift" was published in 1904