Announcement yesterday of a proposal to construct a 15-story office building on stilts over MTA Harvard Sq. property drew mixed reactions from the University and a civic group.

Planned by John B. Sullivan and William J. Chase, the structure would go over the present trackless trolley enhance and exit at Mass Ave. and Cambridge St., opposite the Littauer Center. Excluded in the facilities would be an MTA passenger station and a parking lot on the ground floor.

On Beacon Hill, legislators from Cambridge have already introduced bills to facilitate sale or lease of the land to Sullivan and Chase, who recently promoted construction of the Treadway Motor (on stilts) in Brattle Sq. There has been speculation that success of the new might lead to closing of the MTA in Harvard Sq.

Charles P. Whitlock, Assistant to the President for Civic Affairs, commented last night that such a plan might further the already very complicated situation. "Planning officials feel that this one of the few open spaces left in Cambridge, and should be utilized to improve the whole design of the Square," said.

Cambridge Common

Technically, the area under consideration may lie within the bounds of Cambridge Common, a fact that may cause groups to block the plan. A spokesman for one such group, the Cambridge Historical Society, predicted that the council might vote against the plan because "the Common has historic associations."

Mrs. George Hall, curator of the group, took an opposite stand, however. She expressed hope that the council would vote in favor of the plan, anything "to get that mess out of Harvard Sq."

Sullivan himself forecast that the building would add to the city tax revenues, provide long-needed MTA facilities, and bring added business to the area."

Among the legislators who supported the bill for purchase were John R. , Jr. and John J. Campbell, co-authors of the bill to study best means of utilizing the MTA Bennett St. yard.

Architect for the project, Paul G. '48, also proposed a footbridge running across the Square.