( ( The ( ( ( first and ) ( most simple ) ) technique ) ) ( ( is ( ( the law ) ( of ( ( superposition , ) ( which ( simply ( states ( that ( ( in ( ( a sequence ) ( of ( sedimentary rock ) ) ) ) ( , ( ( ( the rocks ) ( in ( ( the ( upper layers ) ) ( of sediment ) ) ) ) ( are ( younger ( than ( ( the rocks ) ( at ( the bottom ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (ADJP (ADJP (JJ first)) (CC and) (ADJP (RBS most) (JJ simple))) (NN technique)) (VP (VBZ is) (NP (NP (DT the) (NN law)) (PP (IN of) (NP (NP (NN superposition)) (, ,) (SBAR (WHNP (WDT which)) (S (ADVP (RB simply)) (VP (VBZ states) (SBAR (IN that) (S (PP (IN in) (NP (NP (DT a) (NN sequence)) (PP (IN of) (NP (JJ sedimentary) (NN rock))))) (, ,) (NP (NP (DT the) (NNS rocks)) (PP (IN in) (NP (NP (DT the) (JJ upper) (NNS layers)) (PP (IN of) (NP (NN sediment)))))) (VP (VBP are) (NP (NP (JJR younger)) (PP (IN than) (NP (NP (DT the) (NNS rocks)) (PP (IN at) (NP (DT the) (NN bottom)))))))))))))))) (. .)))
The first and most simple technique is the law of superposition, which simply states that in a sequence of sedimentary rock, the rocks in the upper layers of sediment are younger than the rocks at the bottom.
(ROOT (S (S (NP (NP (DT The) (NN law)) (PP (IN of) (NP (NN superposition)))) (VP (VBZ is) (VP (RBS best) (VBN described) (PP (IN by))))) (: :) (S (PP (IN in) (NP (NP (JJ undisturbed) (NNS layers)) (PP (IN of) (NP (JJ sedimentary) (NN rock))))) (, ,) (NP (DT the) (JJS lowest) (NNS layers)) (VP (VBP contain) (NP (DT the) (JJR older) (NNS rocks)))) (. .)))
The law of superposition is best described by: in undisturbed layers of sedimentary rock, the lowest layers contain the older rocks.