MARY F. WILLIAMSPALO ALTO — Dr. Mary Floyd Williams, who wrote historic accounts of the days of the California gold rush and the San Francisco Vigilantes, died on her Ninety-third birthday Tuesday. She apparently suffered a heart attack.Her father, Edward C. Williams, was a miner and lumberman and a member of the San Francisco committee of vigilantes.Jn 1913, a history of the San Francisdb committee of 1351 was the thesis she wrote in obtaining a doctorate degree in philosophy at the age of 50 from the University of California.A paper on the same subject published by the UC press is stilt used by the university as a textbook.Dr. Williams previously lived in Oakland and Berkeley.