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."