( This ( ( was ( followed ( by ( ( ( the ( Paleozoic era ) ) , ) ( which ( ( ( ( started ( with ( the ( Cambrian period ) ) ) ) ( ( ( 600 million ) years ) ago ) ) and ) ( ( ended ( with ( the ( Permian period ) ) ) ) ( ( ( 280 million ) years ) ago ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT This)) (VP (VBD was) (VP (VBN followed) (PP (IN by) (NP (NP (DT the) (JJ Paleozoic) (NN era)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VP (VBD started) (PP (IN with) (NP (DT the) (NNP Cambrian) (NN period))) (ADVP (NP (QP (CD 600) (CD million)) (NNS years)) (RB ago))) (CC and) (VP (VBD ended) (PP (IN with) (NP (DT the) (JJ Permian) (NN period))) (ADVP (NP (QP (CD 280) (CD million)) (NNS years)) (RB ago)))))))))) (. .)))
This was followed by the Paleozoic era, which started with the Cambrian period 600 million years ago and ended with the Permian period 280 million years ago.
(ROOT (S (NP (NP (DT The) (JJ first) (NN period)) (PP (IN of) (NP (DT the) (JJ paleozoic) (NN era)))) (VP (VBD was) (VP (VBN called) (NP (NN cambrian)))) (. .)))