The National Park Service has dropped its controversial plan to exchange parkland in Rappahannock and Warren counties for a privately owned tract on Saddleback Mountain that juts into the Shenandoah National Park, a park service spokesman said yesterday.

"This decision is responsive to strongly held and eloquently expressed feelings" against the trade by Rappahannock residents, said Robert R. Jacobsen. Shenandoah park superintendent.

Barbara Thompson, one of the opponents, said. "We're just delighted. We're very relieved." Thompson, whose husband Stanley led the attack on the proposal, said. "We feel land exchanges should be abandoned. We'll continue to follow this issue until that is resolved."

Jacobsen said yesterday that he still believes that land exchanges are a legal and valid method of obtaining land wanted by the Park Service but he said Interior Department attorneys are reviewing the legal authority for such trades. Opponents had questioned the legality of the proposed trade under both Virginia and federal laws.

Jacobsen had sought 422 acres of privately owned land in the Saddleback Mountain area in exchange for four smaller parcels in the Rappahannock area.

Landowners next to the land to be traded out of the park had complained the land would be damaged by timbering or development. Land values next to the park also are nearly double that of land not adjoining the park.