Matt Osgood, an Orange County developer, owns the lion's share of the 485-acre Santa Barbara Ranch at Naples, which spans both sides of Highway 101, just west of Bacara. His proposal would set aside 134 acres of the scenic property in protected open space, with public trails, picnic areas, horse stalls and a viewpoint from the bluffs.

Another 127 acres would be preserved as orchards, pasture and cropland. Avocados, lemons, oranges, olives and lavender grow there now.

The property would require a change in zoning, called the Naples Planned District, incorporating the residences and open space and agricultural preserves. The existing zoning is for agricultural use and only one home per 100 acres.

"This proposal is the result of five years of discussions and negotiations," Mr. Osgood said Wednesday. "We feel it's a good balance of our property rights as well as maintaining the rural integrity of the coast."

The Surfrider Foundation, Sierra Club, Gaviota Coast Conservancy and other groups have long opposed development west of Bacara. In a study published earlier this year, the National Park Service concluded that the coast from Coal Oil Point to Point Sal was nationally significant for its beautiful canyons and shores, abundant wildlife and historical heritage.

"The community has shown that it favors protecting the resources of the Gaviota coast from suburban sprawl," said Bob Keats, vice chairman of the local Surfrider chapter. "Many are opposed in particular to development on the ocean side of the freeway."

The county Board of Supervisors signed an agreement with Mr. Osgood last year, allowing him to apply to build up to 54 homes at Naples. The Morehart family of Carpinteria, the original property owners, in turn dropped a lawsuit alleging that the county was engaged in an illegal "taking" of their land.

The Moreharts still own 120 acres of the ranch on the south side of the highway. In the past, they have claimed the right to 400 legal lots for homes at Naples, based on speculators' maps that were drawn up more than a century ago. Under Mr. Osgood's agreement with the board, they would drop these claims if the Santa Barbara Ranch proposal is approved.

The family also is challenging county permit requirements for septic tanks and roads at Naples. All of the homes are proposed to be served by septic tanks.

The county planning department now has 30 days to determine whether Mr. Osgood's application is complete. Preparation of an environmental impact report on the project is expected to take at least nine months.

As proposed, the 54 homes would be built on an average four acres each. Their size would range from 4,000 to 10,000 square feet. Most would be single-story, with guest houses and three- or four-car garages.

Nine homes would be built along the bluffs' edge. Another seven on the south side of the highway would form an "equestrian village" with barns. The remaining 38 homes are proposed for the north side of the highway.