About 175 members of the Organization for Black Unity left University Hall at 2:30 p.m. yesterday after occupying the building for six hours. The students-all black-left the building to the sound of beating war drums after OBU president Phillip Lee, a third-year Law student, signed an agreement with Archibald Cox, professor of Law and University spokesman.

The agreement stated that:

No contracts will be executed on Gutman Library (the new Ed School Library) until the implementation committee has had an opportunity to resolve the other issues.

At least one black subcontractor on Gund Hall be guaranteed if one is willing to do the work at a price reasonably comparable to other bids.

The implementation committee meeting be held at 4 p.m. Monday in Larsen Hall 103 to work out details on the demands relating to painters and construction workers.

The composition of the committee to evaluate the painters helpers will include, in addition to three members of the Contractors Association of Boston, Erna A. Ballantine, Harold Washington, and Derrick A. Bell.

Miss Ballantine is the former chairman of the Massachusetts Commission Against Discrimination; Washington is a lecturer in Afro-American. Studies, and Bell is a lecturer at the Law School.

The implementation committee and the committee to evaluate the painters helpers stemmed from proposals made by the Administration last week. The original painters helpers committee proposal said that the committee would include only three members of the Contractors Association of Boston. The implementation committee is to include ten members-five from the Administration and five from OBU.

Leslie P. Griffin 70, president of Afro, said that the agreement is not final. "We just felt it wouldn't be to our advantage to stay until they called in the cops." Griffin also said that the demonstrators did not discuss whether to demand amnesty for their action. "The consensus was that sometimes you have to take responsibility for what you do." he said.

Ewart Guinier, chairman of the Afro-American Studies Department who helped negotiate the Cox-Lee agreement, characterized it as a "statement of faith on the part of both sides." He said that Harvard's promise that there would be no contracts executed on Gutman Library was the key indication of the University's willingness to bargain in good faith. Previously Harvard had only promised to review the contract.

The agreement was a condensation of a letter Cox wrote Thursday night and had intended to send to OBU yesterday morning. By the time he was ready to send the letter. however, University Hall was occupied. The letter was finally delivered at about 10:30 a.m. yesterday to the demonstrators.

About 100 OBU members entered the building at about 8:15 a.m. It had been unlocked earlier in the morning as regular procedure, but no members of the administration had arrived in their offices when OBU went in. When Dean May arrived for work the building was locked and barricaded from the inside. May spoke through a bull horn to the demonstrators and told them that they would be charged with trespassing unless they left. About 15 per cent of the demonstrators were not Harvard students. but came from other OBU campus groups.

"Students participating in this demonstration are forcibly interfering with freedom of movement of university officers and employees. All students are forbidden to remain here any longer and are ordered to leave immediately," May said.

The Council of Deans and House Masters met at President Pusey's house at 2 p.m. Cox called the meeting earlier in the day Pusey had been in Washing-ton but flew back around noon after consultations with Cox. The Council of Deans and Pusey decided to approve the document to which OBU later agreed.

Cox then went over to University Hall and met with Lee, who had received a copy of the proposed agreement earlier in the day. According to Cox they "talked briefly and then put the agreement up against the wall and signed it."

At 1 p.m. a group of white radicals gathered at Lehman Hall for a meeting called by SDS. Groups at the meeting included the November Action Committee, at least one Weatherman, and SDS. The meeting voted to conduct a march in support of OBU. They left Lehman Hall at 1:30 p.m. and marched to Radcliffe chanting "power to the people." By the time they returned to the Yard OBU had left University Hall.

Issues Unresolved

The Cox-Lee agreement leaves several issues unresolved. Yesterday's first OBU statement said that only about five per cent of Harvard employees are black and demanded that Harvard employ 20 per cent blacks. Cox denied that this demand had been discussed. The exact membership of the implementation committee is also still to be worked out.

Most black students, however, felt that an acceptance of at least the broad aims of their demands was implicit in the Cox-Lee agreement. One black student said that the aim of taking over University Hall had been to "get the University to take our demands seriously. Apparently they have." Another said that this is only one step in the campaign, and that OBU is prepared to take further action if necessary.

There were no incidents of violence during the day, although two bomb threats were telephoned to University police. The University police were in contact with Cambridge police throughout the day, but Harvard did not seek a court injunction against the demonstrators. One Cambridge police lieutenant said that, "Harvard had the situation well in hand."