( ( ( Two types ) ( of ( surface waves ) ) ) ( ( exist ( on ( ( solids -- ) ( ( Rayleigh and ) Love ) ) ) ) . ) )
(ROOT (S (NP (NP (CD Two) (NNS types)) (PP (IN of) (NP (NN surface) (NNS waves)))) (VP (VBP exist) (PP (IN on) (NP (NP (NNS solids)) (: --) (NP (NP (NNP Rayleigh)) (CC and) (NP (NN Love)))))) (. .)))
Two types of surface waves exist on solids -- Rayleigh and Love.
(ROOT (S (NP (EX There)) (VP (VBP are) (NP (NP (CD two) (NNS types)) (PP (IN of) (NP (NN surface) (NNS waves))))) (. .)))