who suggested that the sea floor was moving and not just the landmasses
Seafloor spreading Earlier theories (e.g. by Alfred Wegener and Alexander du Toit) of continental drift postulated that continents "ploughed" through the sea. The idea that the seafloor itself moves (and also carries the continents with it) as it expands from a central axis was proposed by Harry Hess from Princeton University in the 1960s.[3] The theory is well accepted now, and the phenomenon is known to be caused by convection currents in the asthenosphere, which is ductile, or plastic, and the brittle lithosphere.[4][clarification needed]
Caesar's invasions of Britain No information about harbours or other landing-places was available to the Romans before Caesar's expeditions, so Caesar was able to make discoveries of benefit to Roman military and trading interests. Volusenus's reconnaissance voyage before the first expedition apparently identified the natural harbour at Dubris (Dover), although Caesar was prevented from landing there and forced to land on an open beach, as he did again the following year, perhaps because Dover was too small for his much larger forces. The great natural harbours further up the coast at Rutupiae (Richborough), which were used by Claudius for his invasion 100 years later, were not used on either occasion. Caesar may have been unaware of them, may have chosen not to use them, or they may not have existed in a form suitable for sheltering and landing such a large force at that time. Present knowledge of the period geomorphology of the Wantsum Channel that created that haven is limited.