Martha Lewis Black, 72, a retired chief investigator for the D.C. Minimum Wage Board, died of cancer Saturday at Sibley Memorial Hospital.

Miss Black attended the old Harrisonburg State Normal School in her native Virginia.

She taught English and history in Augusta County, Va., public schools for isx years, and then managed her family's farm near Stuarts Draft, Va.

During the late 1930s she was riding director at Camp Allegheny for Girls in Lewisburg, W. Va., then worked at the DuPont chemical plant in Waynesboro, Va., during World War II.

Miss Black came here in 1946, and worked for the D.C. public schools before joining the Minimum Wage Board as an investigator. She was named chief investigator in 1951, and in 1959, received the board's first certificate for superior performance. She retired in 1964.

She was a founder of the Glenmore Hunt Club in Staunton, Va., and a frequent winner of the five-gaited class in Shenandoah Valley horse shows.

Miss Black lived in Washington with longtime friend, Elizabeth Clagett Clark.

Survivors include a sister, Mrs. Dixon Flanary, of Norton, Va.

The family suggests that expressions of sympathy be in the form of contributions to the Tinkling Springs Presbyterian Church in Fishersville, Va.