R. Dorsey Watkins, 85, a senior judge and a former chief judge of the U.S. District Court in Baltimore, died of cancer March 19 at his home in Catonsville, Md.

Judge Watkins, a Baltimore native, was appointed to the federal bench in 1955 by President Eisenhower. For 25 years before that, he was a partner in the law firm that is now known as Piper and Marbury.

Judge Watkins was named chief judge of the federal court here in June 1970, but had to relinquish the title three months later when he reached the mandatory retirement age of 70. After his retirement, he served as a senior judge.

Among well known cases he heard were criminal matters arising from Maryland's savings and loan scandals in the 1960s and other criminal matters involving associates of former vice president Spiro T. Agnew in the 1970s.

He earned a bachelor's degree at Johns Hopkins University in 1922 and a law degree at the University of Maryland in 1925. He was an instructor at the University of Maryland law school for 42 years and taught advanced commercial law at Johns Hopkins from 1926 until 1955.

His wife, Marion Turner Watkins, died in 1973. Survivors include a daughter, E. Roberta Watkins of Randallstown, Md., and a brother, Joseph M. Watkins of Sparks, Md.