A towering bronze likeness of Supreme Court Justice Thurgood Marshall was dedicated here today as a tribute from the city of Baltimore to the first black man, and the city's first native son, to sit on the Supreme Court.

The ceremony, which began as a celebration of Marshall's legal courage and achievement, climaxed with a sobering directive from the 72-year-old honoree as he stood next to the commanding statue outside Baltimore's new federal courthouse.

"Some Negroes feel we have arrived. Others feel there is nothing more to do. I just want to be sure that when you see this statue, you won't think that's the end of it. I won't have it that way. There's too much work to be done," Marshall said. He spoke from a platform weighted with dignitaries to an audience of 250 Baltimoreans.

The statue protrays Marshall in his judicial robes with folds that cascade powerfully down its length. Its rugged, uneven surface caught the midafternoon light yesterday and glistened brightly throughout the ceremony.

On the podium with Marshall sat five of his fellow Supreme Court justices, as well as Gov. Harry Hughes, Mayor William Donald Schaefer and Marshall's long-time friend and colleague, Clarence M. Mitchell, former director of the National Association for the Advancement of Colored People.

They gathered to honor Marshall the justice, but the speakers talked more of Marshall the advocate -- the civil rights lawyer who, as special counsel for the NAACP legal defense fund, argued many trail-blazing desegregation cases in the 1950s.

It was in that role that Marshall argued before the Supreme Court and won the seminal school desegregation case, Brown vs. Board of Education in 1954, that laid the groundwork for a generation of civil rights law.

Calling Marshall "one of the great advocates in the history of the Supreme Court," Justice William Brennan said that Marshall, as an NAACP lawyer, "started this nation on the road to the end -- not yet arrived -- of racial discrimination."

It was that spirit of advocacy that sculptor Ruben Kramer said he sought to portray in the 8-foot-7-inch tall figure that he created."What I wanted to do is take this man here and show him in the position that he holds rather than in the position that he stands," Kramer said. He noted that Marshall stands with his shoulders slightly stooped.

Mitchell said he was pleased that Marshall used the occasion to call for further advancement of the rights of black people.

"The progress in Baltimore is the same as you see in the rest of the country. We've made tremendous progress but we know we're not where we ought to be," Mitchell said after the ceremony.

He cited continuing disproportionate levels of unemployment in Baltimore's black community and barriers to jobs and educational opportunities. Some blacks in the audience interpreted the placement of Marshall's statue as a slight, since it stands behind the courthouse, rather than in front of it, and faces away from the street.

"It's the old cliche: Blacks at the back door," commented one woman who refused to give her name. However, it was pointed out that the statue stands across the street from Baltimore's new harbor development, including the Civic and Trade Centers.

Marshall, the son of a steward at an exclusive Chesapeake Bay boat club for white men only, had to leave the state to get his law degree because the University of Maryland at the time did not accept black students. He later helped argue the case that struck down that barrier.