(Πετραία), is the name of one of the Oceanides, and also occurs as a surname of Scylla, who dwelt in or on a rock. 357 (Hes. Th. 357 ; Hom. Od. 12.231.)
[L.S]A Dictionary of Greek and Roman biography and mythology
Smith, William
A Dictionary of Greek and Roman biography and mythology. William Smith, LLD, ed. 1890