Ballatine got out of his truck and headed into the Potomac. Trevathon's 1986 Buick Skylark was about 35 feet from the bank in water about chest deep, Ballantine said.
He said he could hear screams from Joann Kovach, who had gotten out of the car.
But Ballantine couldn't make out her words. "The river was loud," the Shepherdstown man said.
Then he realized Kovach wanted him to go to the car. Trevathon, the child and a dog were still inside.
The animal jumped out, and Ballantine said he used his elbow to smash open the rear window on the driver's side. The child was sitting in the back seat of the passenger's side.
"I don't know how I did it, but I got him out," Ballantine said Sunday.
He carried the boy to the shore. "I said, `Here, somebody take this' and handed him to the woman on the shore,'" Ballantine said.
He and another man then helped Trevathon, 22, of Shepherdstown, get out of the car, Ballantine said.
Firefighters from the Independent Fire Co. dive-rescue team hooked a tow line to the car and a tow truck pulled it out.
No one was injured and no charges were filed, Jenkins said.
The damage to the truck was estimated at $500. The car was a total loss, Jenkins said.