( The ( ( ( ( Cambrian ( -LRB- ( or ( -RRB- ( is ( ( ( the ( first ( geological period ) ) ) ( of ( ( ( the ( Paleozoic Era ) ) , ) ( lasting ( ( ( ( from to ) million ) years ) ago ) ) ) ) ) ( -LRB- ( mya -RRB- ) ) ) ) ) ) ) ) and ) ( is ( succeeded ( by ( the Ordovician ) ) ) ) ) . ) )
(ROOT (S (NP (NNP The)) (VP (VP (VBD Cambrian) (SBAR (S (-LRB- -LRB-) (NP (CC or)) (-RRB- -RRB-) (VP (VBZ is) (NP (NP (DT the) (JJ first) (JJ geological) (NN period)) (PP (IN of) (NP (NP (DT the) (JJ Paleozoic) (NN Era)) (, ,) (VP (VBG lasting) (ADVP (NP (QP (IN from) (TO to) (CD million)) (NNS years)) (RB ago))))) (PRN (-LRB- -LRB-) (NP (NN mya)) (-RRB- -RRB-))))))) (CC and) (VP (VBZ is) (VP (VBN succeeded) (PP (IN by) (NP (DT the) (NNP Ordovician)))))) (. .)))
The Cambrian ( or ) is the first geological period of the Paleozoic Era, lasting from to million years ago (mya) and is succeeded by the Ordovician.
(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)))) (. .)))