Prince George's County Executive Parris N. Glendening elevated his budget director yesterday to the county's top administrative post, making Major F. Riddick Jr. the first black person in the Washington suburbs to hold the highest-ranking county staff position.

Riddick's promotion to the $107,000-a-year job as chief administrative officer was one of 13 high-level appointments Glendening announced yesterday that he said reflected "the heterogeneity of Prince George's County." Of the total, most promoted from within, eight are black and six are women in a county that is about 50 percent black.

"I selected the very best in terms of people who moved up through the administration, some black, some female, some white male," Glendening said. "There were no predetermined ratios or goals."

Riddick, 40, said, "Obviously, there's some historic significance. This makes a fairly strong statement by this administration in terms of his commitment to a diverse and progressive team." Glendening said Riddick was chosen from six finalists and is the first black in Maryland to be a county administrative officer.

In the past, Glendening has been criticized by some segments of the black community for not consulting them on the selection of a police chief and the effort to extend the school superintendent's contract. Both are white men.

Riddick replaces John P. Davey, 38, who is leaving after four years in the job to practice law, possibly with Lance Billingsley, Glendening's campaign manager and head of the county's economic development corporation. Glendening said Davey, who earned $112,000 in the post, will continue to advise him informally on political and policy matters.

Also leaving is Joel Rozner, 42, Glendening's chief of staff, who will become a partner and open a Prince George's office for the politically connected law firm of Rifkin, Evans and Silver.

Rozner's replacement is John T. Willis, a Baltimore lawyer specializing in real estate and land use law who is active in Democratic politics. The chief of staff under Glendening has often acted as a key political operative.

Others named yesterday are Andre Gingles, deputy chief of staff; Lynda Green, deputy chief administrative officer for human services; Alvin Nichols, deputy chief administrative officer for business development; Donna Crocker, special assistant to the chief administrative officer.

Also named were Marita Brown, succeeding Riddick as budget director; Raymond Skinner, director of housing and community development; Dennis Brownlee, director of the Office of Central Services; Adrian Gardner, executive director of the Minorities Business Opportunities Commission; Dorothy Bailey, executive director of the Commission for Families; Michele Tucker, executive director of the Consumer Protection Commission; and Linda Botts, director of the Office of Child Support Enforcement.