The Roberts family, which has owned the last undeveloped canyon in Malibu since the 1930s, has given an organization of environmentalists an extension on Saturday's deadline to buy 345 acres of the rural property.
The Trust for Public Lands has until the end of February to purchase the parcel, said Bill Dempsey, project manager for the environmental group formed to acquire private property for public use.
"We're comfortable that we have an informal understanding with the Roberts that they will keep the property off the market while they're talking with us," Dempsey said.
The original agreement called for the trust to buy the land by the end of 1986, a year after it had purchased a $250,000 option. The trust raised $1 million but needs $3 million to close the deal.
To avoid losing the land, the trust offered to buy only 150 acres and asked the Roberts family to wait until Dec. 31, 1988, for it to purchase the remaining 195 acres.
The Roberts family, Florence Roberts and sons John F. and James L., agreed to keep the property off the market while it considers the offer.
The 556-acre Roberts Ranch contains Solstice Canyon, the last large canyon in the Santa Monica Mountains that remains undeveloped all the way to the beach. The property has mountain scenery, areas for campgrounds and a stream that runs throughout the year.
Earlier this year, the Santa Monica Mountains Conservancy, a state agency that acquires parkland in the Santa Monica Mountains, purchased 211 acres of Roberts Ranch for about $2.5 million. The trust offered to buy the remaining 345 acres for $3 million.