Many of the same highly-productive, sheet-like forms (Figs 3, 5 and 7) have been noted (Bokenham and Stephenson, 1938; Northcraft, 1948; Fahey, 1953; Murray and Littler, 1978; Sousa, 1979b) to be among the earliest colonizers of disturbed rocky-intertidal substrates. Connell's (1975)...