( We ( ( ( find ( ( an ( ordered succession ) ) ( of ( magnetized rocks ) ) ) ) ( on ( ( the ( ocean floors ) ) ( that ( ( record ( ( ( ( 100 and ) more ) ( full reversals ) ) ( of ( ( the ( present direction ) ) ( of ( the ( magnetic poles ) ) ) ) ) ) ) ( during ( ( the ( past couple ) ) ( of ( ( ( 100 million ) years ) ( of ( seafloor spreading ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP We)) (VP (VBP find) (NP (NP (DT an) (JJ ordered) (NN succession)) (PP (IN of) (NP (JJ magnetized) (NNS rocks)))) (PP (IN on) (NP (NP (DT the) (NN ocean) (NNS floors)) (SBAR (WHNP (WDT that)) (S (VP (VB record) (NP (NP (QP (CD 100) (CC and) (JJR more)) (JJ full) (NNS reversals)) (PP (IN of) (NP (NP (DT the) (JJ present) (NN direction)) (PP (IN of) (NP (DT the) (JJ magnetic) (NNS poles)))))) (PP (IN during) (NP (NP (DT the) (JJ past) (NN couple)) (PP (IN of) (NP (NP (QP (CD 100) (CD million)) (NNS years)) (PP (IN of) (NP (NP (NN seafloor)) (VP (VBG spreading)))))))))))))) (. .)))
We find an ordered succession of magnetized rocks on the ocean floors that record 100 and more full reversals of the present direction of the magnetic poles during the past couple of 100 million years of seafloor spreading.
(ROOT (S (NP (NP (NNS Rocks)) (PP (IN on) (NP (NN ocean) (NN floor)))) (VP (VBZ is) (NP (NN evidence)) (SBAR (IN that) (S (NP (JJ magnetic) (NNS reversals)) (VP (VBP occur))))) (. .)))