Strata (1990) is a collaborative album by the U.S. ambient musicians Robert Rich and Steve Roach. Robert Rich's influence on this album is strong, with complicated mixes featuring various acoustic sound sources and Rich's own brand of organic synthesis called "glurp". The two artists collaborated again (with the credits in the reverse order) on their 1992 album Soma. There is a strong sense of surrealism throughout the album. The seventh track's title refers to The Persistence of Memory by Salvador Dalí, who died in 1989 when recording of this album began, and to whom the piece is dedicated.