A Cambridge real estate salesman's $10-100 million scheme to build a super-structure over one-sixth of the Charles River Basin stirred up bitter controversy at a City Council hearing yesterday.

John Briston Sullivan petitioned the Council to zone the submerged land northeast of M.I.T. Sullivan's purpose is to give Cambridge more taxable land by building a semi-industrial development on pilings over the seven acres of land in question, on which he holds an option.

Strong opposition was voiced by Boston and Cambridge residents, who claimed that such a development would mar the beauty of the landscape and thereby reduce land values.

The major opposition to Sullivan's plan, however, was rendered by Charles W. Greenough '19, Metropolitan District Commissioner, who claimed that the Commission "has the responsibility" to guard the public interest over the Basin, even though the land may be privately owned.

Greenough declared that the MDC has to approve any building plans on this land and that the Commission has already voted against Sullivan's plan.

Sullivan contends that since one third of Cambridge is tax exempt land owned by educational and charitable organizations such as Harvard, any further city development should be on taxable land.

It was also pointed out that the proposed structure would interfere with community sailing and Harvard and M.I.T. crew racing.