An exhausting three-day ordeal ended yesterday for an elderly Prince George's County couple when rescue workers found the overturned car in which they had survived since Monday after it ran off a rural road in the eastern part of the county.

James Francis Henry, 75, and his wife, Margaret Elizabeth, 62, of 3002 Church Rd., Mitchellville, were taken last night to Prince George's General Hospital for treatment after spending three chilly nights in their auto, which ran off Woodmore Road and into a deep ditch.

According to preliminary reports, both appeared to be suffering from dehydration. Neither apparently had eaten since Monday. In addition, rescue and medical workers said Henry appeared to show signs of confusion.

Authorities said that Mrs. Henry was apparently trapped in the vehicle, which they said was almost completely hidden from anyone passing on Woodmore Road.

The husband reportedly was able to extricate himself, and occasionally made his way to the road, which is about a mile or so from the couple's home, but it appeared that he was not able to summon help.

Each of the nights until the couple was found -- in which temperatures plunged to the 40-degree level and below -- was spent in the car, turned on one side in the ditch.

The Henrys were reported missing to police by a son at about 5:30 p.m. on Monday.

A lookout was issued, according to county police Lt. Harold Wilson, but the couple could not be located.

In midafternoon yesterday, Wilson said, a bicyclist pedaling along Woodmore Road heard shouts. They were voiced by Mrs. Henry from inside the car, which, police noted, could be spotted only by someone who stopped at the edge of the road and peered down the steep embankment.

After the car, described as brown and about 10 years old, was finally discovered, police and fire department rescue squads were called and the couple was taken first to the Bowie Health Center, and then to the hospital.

Witnesses said Henry appeared barely conscious as he was carried in on a stretcher. They said his wife, described by a storekeeper in their neighborhood as the driver of the family car, complained of a possible back injury.