Plate Tectonics Versus Earth Crust Displacement???

Detractors

    * H. Jeffreys - a reknown seismologist, knew that mantle was strong (behaved as an elastic solid for earthquake waves, could hold up mountain ranges). Argued that Wegener's proposed driving mechanism, tidal forces, was a million times too small to deform and displace mantle as continents moved through it.
    * AAPG Symposium (1926) - rejects continental drift in favor of geosyncline theory. Geophysical objections remain strongest.