. ▁Is acks , ▁Edward ▁Bull ard , ▁X avier ▁Le ▁P ich on , ▁Dan ▁McK en zie , ▁W . ▁Jason ▁Morgan ▁and ▁John ▁Tu zo ▁Wilson . ▁Prior ▁to ▁this , ▁people ▁had ▁ideas ▁of ▁contin ental ▁dr ift , ▁but ▁no ▁real ▁evidence ▁came ▁until ▁the ▁late ▁ 2 0 th ▁century . ▁Alexander ▁von ▁H umb old t ▁observed ▁in ▁the ▁early ▁ 1 9 th ▁century ▁the ▁geometry ▁and ▁ge ology ▁of ▁the ▁sh ores ▁of ▁contin ents ▁of ▁the ▁Atlantic ▁Ocean . ▁James ▁H utton ▁and ▁Charles ▁Ly ell ▁brought ▁about ▁the ▁idea ▁of ▁grad ual ▁change , ▁uniform itar ian ism , ▁which ▁helped ▁people ▁co pe ▁with ▁the ▁slow ▁dr ift ▁of ▁the ▁contin ents . ▁Alfred ▁Weg ener ▁spe ar head ed ▁the ▁original ▁theory ▁of ▁contin ental ▁dr ift ▁and ▁spent ▁much ▁of ▁his ▁life ▁devoted ▁to ▁this ▁theory . ▁He ▁proposed ▁" P ang ae a ", ▁one ▁un ified ▁giant ▁continent . ▁ ▁During ▁the ▁development ▁of ▁contin ental ▁dr ift ▁theory , ▁there ▁was ▁not ▁much ▁expl oration ▁ ▁of ▁the ▁ocean ic ▁part ▁of ▁the ▁world , ▁only ▁contin ental . ▁Once ▁people ▁began ▁to ▁pay ▁attention ▁to ▁the ▁ocean , ▁ge olog ists ▁found ▁that ▁the ▁floor ▁was ▁spread ing , ▁and ▁in ▁different ▁rates ▁at ▁different ▁sp ots . ▁ ▁There ▁are ▁three ▁different ▁main ▁ways ▁in ▁which ▁pl ates ▁can ▁move : ▁transform , ▁diver gent , ▁and ▁Con ver gent . ▁As ▁well ,