To mark the Sept. 11, 2001, terrorist attacks, St. Peter’s Episcopal Church and Adas Yoshuron Synagogue, both in Rockland, plan an interfaith service for the community. “Ashes, Stones and Flowers” will be the special litany, and people are welcome to come and go at their convenience next Saturday, Sept. 11. St. Peter’s, on White Street, will begin its service at 8 a.m. with the tolling of a bell, followed by periods of silent meditation, prayer, readings and music. Subsequent tolling will mark key moments of the day. The St. Peter’s service will conclude with a symbolic sharing of bread and salt, ancient symbols of journey and peacemaking. The litany was brought to Rockland by Rabbi Amita Jarmon of Adas Yoshuron, 50 Willow St., where the liturgy is being coordinated with Sabbath morning prayer and Torah service at 9:30 a.m.