The new mavricks of the legal profession - lawyers trying to provide cut rate services to middle-income Americans - challenged the organized bar today in the Maryland Court of Appeals' first public hearing over the rules that govern the conduct of attorneys in the state.

The issue was lawyer advertising - which the young mavericks argue is necessary for them to get the high volume business needed to keep their fees low, while the establishment lawyers and the organized bar feared lawyer advertising could mislead the public, unless it is tightly controlled.

Today's hearing before the red-robed justices of Maryland's highest court was the first major clash in the public arena over limitations on lawyer advertising since the U.S. Supreme Court ruled in June that lawyers have the right to advertise, but gave the states the right to set specific rules.

So far, according to the American Bar Association, only two states - Mississippi and Missouri - have issued final rules on lawyer advertising. In both cases they are more restrictive than the ones suggested by ABA, which the Justice Department has said fail to meet the Supreme Court guidelines.

Maryland's Court of Appeals had the recommendation of its rules committee before it today. In a letter to the court last week, Assistant U.S. Attorney General John H. Shenefield said those proposals "appear to prohibit the very advertising which the Supreme Court found constitutionally protected."

The Maryland proposal would ban advertising on radio and television; require lawyers to advertise the maximum fees not the minimum charges now being advertised and force lawyers to include a complete description of services covered by the advertised fee in type as large as that listing the fee.

Dean Michael J. Kelly of the University of Maryland School of Law, a member of the subcommittee that drafted the proposed rules, said the restrictions were recommended because of the possibility of lawyer advertising misleading the public.

Television ads, he continued, were banned because its "impressionist nature" could leave "subconscious and subliminal" ideas that might also be misleading.

He was countered by Richard V. Falcon, a law professor at Maryland who represented the Baltimore-based Legal Clinic of Cawley, Schmidt and Sharrow. He called the proposed regulations "a gross insult to a majority of the members of the bar" because they assume lawyers "are just waiting to deceive consumers."

While today's arguments darted among the various provisions of the proposed regulations, the focus of the three-hour hearing was on the different views of the way law should be practiced that are held by the organized bar and a younger group of lawyers trying to carve out a new type of practice for themselves.

"The real issue," said Catholic University law professor Harvey L. Zuckman, "is the clash and conflict between the established method of delivering legal services as opposed to the rise of a new way of doing business - legal clinics - which are a supermarket of limited services trying to reach the 70 per cent of the American public who have no contact with lawyers."

He said advertising is necessary for these clinics to attract clients. Indeed, the Supreme Court case was brought by the legal clinic of Bates & O'Steen of Phoenix, Ariz.

Yet Alfred L, Scanlan, a Washington-Bethesda lawyer and member of the Maryland Bar Association's special committee on advertising, told the court that "the less competent and less worthy members of the legal profession will lead the rush to advertise . . . in order to attract clients who they couldn't attract on the basis of their ability and integrity."

He cited newspaper advertisements by two Maryland lawyers, whom he did not name. One, he said, had been convicted of assault and battery and the other had received a private reprimand from the state's Attorney Grievance Committee. In neither case was the blot on the lawyers' records mentioned in the ads, said Scanlon.

The Court of Appeals' rules committee had hoped the justices would decide on final recommendations next week so they could take effect Jan. 1. But Rules Committee Chairman Kenneth Proctor said after today's hearing that timetable no longer seemed possible.

Chief Judge Robert C. Murphy called today's hearing "unique in the 300-year history of the Maryland Court of Appeals" because it was opened to the public and consumers of legal services were invited to speak.