Ellis T. Williams, 75, a retired insurance and tax specialist with the U.S. Forest Service and a former presiding clerk of the Religious Society of Friends in this area, died of cancer Sept. 8 at the Hospice of Northern Virginia.

Mr. Williams, who lived in Washington, was born in Jenkintown, Pa. He graduated from Yale University and the Harvard business school and went to work for an insurance company in Philadelphia.

During World War II he declared himself a conscientious objector and enrolled in the Civilian Public Service where he worked in forests. After the war, he was acting executive secretary of the Southern California regional office of the American Friends Service Committee.

He joined the Forest Service in Philadelphia in 1950 and transferred to Washington in 1951. He retired in 1972. He published more than 50 papers on taxation of forest and timber.

After leaving the government, he was an adjunct professor of forestry economics at Syracuse University.

Mr. Williams was a former presiding clerk of the Friends Meeting of Washington of the Baltimore Yearly Meeting of Friends, a chairman of the board of Sidwell Friends School in Washington, a director of the Council of Churches of Greater Washington, and a member of the advisory board of the Earlham School of Religion in Richmond, Ind., and the corporation of Haverford College in Haverford, Pa. He also was a member of the Assembly of the Interfaith Conference and the Cosmos Club.

Survivors include his wife, Daphne Reynolds Williams, and a son, Thomas P. Williams, both of Washington; a brother, H. Justice Williams of Philadelphia, and a sister, Mrs. Theodore K. Meltzer of San Francisco.