Alexandria city officials agreed nine years ago to allow homes to be built on a hilly 88-acre tract that is now subject to severe earth slides despite warnings that the land there was likely to slide.

Both City Planning Commission and City Council members overruled the objections of city engineers and planners and agreed to allow rezoning of the site in the Seminary Ridge subdivision.

The action allowed a developer to begin building single-family homes on the land, where recent land slides have threatened a $165,000 home and where other homes have lost large sections of their yards to slippage.

City officials have disclaimed any responsibility for the slides and have said that the problem in an issue between the homeowners and the builder.

Yet on July 29, 1969, city records show that Glenn B. Anderson, a district conservationist with the Northern Virginia office of the U.S. Soil Conservation Service gave city officials notice of potential trouble with the soils. In his letter, Anderson noted that the tract contained soils that "caused serious slippage problems in nearby areas" and cautioned that the site was "highly susceptible to slips and slides.

His warning was echoed by a city planning report that cautioned that the yards in the proposed development "will require constant maintenance to keep them from sliding."

But these warnings were unanimously rejected by the planning commission and the council, which approved the rezoning.

The developer, Pulte Home Corp., had originally considered building town houses on the land, with an old Civil War fortification there being preserved. When neighboring citizen associations voiced strong opposition to the town houses, Plute went before the city with a new proposal calling for single-family houses - a plan that would destroy the old Fort Worth as well as permit construction on steep slopes that had been called "highly unstable."

The neighbors who had been angry over the town house plan backed off their oppostion and the council approved the single-family housing plan. "I guess the citizens' associations had more clout than we did," said Dayton L. Cook, who was then the city's engineer and one of the opponents of the single-family home development plan.

Alexandria City Manager Douglas Harman, who had earlier disclaimed city responsibility for the troubles with the lands said yesterday he was "not in a position to comment" on the 1969 city reports. "I was not here" at that time, he said. "What the staff had to say is a matter of record."

Residents of the Seminary Ridge development whose homes have been threatened by the slides have been furious at the city for allowing the homes to be built on soils containing highly unstable marine clay, which runs through the tract.

Officials of Pulte Home, located in suburban Maryland, could not be reached for comment yesterday.

Marine clay "is a plastic clay with a high liquid limit causing it to be very unstable," Anderson, the conservationist told the city in his 1969 letter. "When saturated, such soils are highly susceptible to slips and slides," he said.

Cook, now city director of transportation and environmental services, said he opposed the rezoning - which permitted 234 houses throughout the tract - and favored instead town houses clustered on a relatively flat area, with the steep sections and the old Civil War fortification preserved.

At the 1969 hearings the question of whether the old fort would be preserved was as much an issue as the soils. M. W. Belcher Jr., a member of the Seminary Hills Citizens Association and opponent of the premliminary plan calling for town houses, said yesterday: "It would have been out of keeping with the area. This is a single-family-home community . . . I feel no regret that the fort was bulldozed. I don't think it would have been practical to preserve it."

However, the staff report that went to the Planning Commission in 1969 said: "It should be noted that this fort is better preserved than was Fort Ward prior to its restoration."