A 70-year-old Arlington woman who had wandered from her home and down a 50-foot embankment was rescued near the Potomac River Thursday night after a six-hour search by 50 Arlington, Fairfax and District police and firefighters, police said.

Mary Borzzi, of 405 N. Chain Bridge Rd., was rescued at 2:30 a.m., when a District police helicopter pilot decided to make one additional pass over a section of the river near Chain Bridge, police said. Borzzi was treated at Arlington Hospital and then transferred to Sibley Hospital, where she remained yesterday.

Police said Borzzi's sister, Gertrude, reported Mary Borzzi missing at about 8:30 p.m. Thursday night. Some 50 police and firefighters searched the wooded and rocky area into the night, as helicopter pilot Roy Collins circled overhead.

Shortly before 2:30 a.m., Collins said, he was asked by Arlington police to make one final pass over the search area with his searchlight and then head home. But Collins said he and officer Barbara Kornutick, his observer on the search, decided to make one more try. Finally, they spotted Borzzi, and while Collins hovered the helicopter overhead, paramedics climbed down the cliff to offer first aid.

Borzzi was then lifted into a 19-foot D.C. Harbor Patrol boat and ferried down river to Roosevelt Island, where she was transferred to an Arlington County ambulance and taken to Arlington Hospital.