Police are investigating a hit-and-run automobile accident that killed a 21-year-old woman early yesterday, a Baltimore County police spokesman said.

Police said Lorranine Boggs of Baltimore was struck by a dark green car about 1:55 a.m. in the 9600 block of Bel Air Road.

Boggs was apparently walking on the road when she was hit by the vehicle, which was heavily damaged in the front, a spokesman said.

In an unrelated accident yesterday, a father and his 5-week-old daughter died in a head-on collision yesterday, state police said.

Police said Robert Miller, 18, of Street, and his daughter, Donna, died in the 1:40 p.m. crash on Route 165 in Harford County. Three other persons were injured in the crash.

Police said Miller lost control of his car on the wet pavement and collided with a vehicle traveling southbound on the highway.

Michelle Miller, 18, was listed in critical condition at the University of Maryland Shock Trauma Center in Baltimore. The infant was sitting on her mother's lap and crashed through the windshield on impact, police said.

The driver of the other car, Rowland Parthree, 65, of Delta, Pa., was listed in serious condition at York County Memorial Hospital. Martha Parthree, 62, was also in serious condition at the hospital.