( ( The ( mud layers ) ) ( ( ( formed ( by ( ( the ( ( slow continuous ) rain ) ) ( of ( finer sediment ) ) ) ) ) ( settling ( from ( the ocean ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN mud) (NNS layers)) (VP (VBD formed) (PP (IN by) (NP (NP (DT the) (ADJP (JJ slow) (JJ continuous)) (NN rain)) (PP (IN of) (NP (NN finer) (NN sediment))))) (S (VP (VBG settling) (PP (IN from) (NP (DT the) (NN ocean)))))) (. .)))
The mud layers formed by the slow continuous rain of finer sediment settling from the ocean.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NNS sediments)) (VP (VB settle) (PRT (RP out)) (PP (IN of) (NP (NN water)))))) (, ,) (NP (PRP they)) (VP (VBP form) (NP (JJ horizontal) (NNS layers))) (. .)))
When sediments settle out of water, they form horizontal layers.