Clay S Harder Sr., 90, 43 E Morris St, died Thursday May 9, 1991 at home. He was born April 28, 1901 in Bath, to George and Carrie Dudley Harder. He was a graduate of Haverling High School and a 1925 graduate of Syracuse University's School of Architecture. For many years he was associated with the architectural firm of Fudge and Underhill of Elmira. He also operated his own architectural practice in Bath and had collaborated on such projects as the Syracuse War Memorial nd the Bethesda and St. James Mercy hospitals, both in Hornell. He was a member and past member of the Steuben Masonic Lodge of Bath, and a member of the Royal Arch Masons of Bath and the Bath Presbyterian Church. Surviving are: his wife, Ruth Kittler Harder;one daughter, Ann (Mrs. Edward) Vought of Hammondsport; one son, Clay S Jr. of Syracuse; five grandchildren and five great-grandchildren. Calling hours are 7-9 p.m. Sunday in Fagen's Funeral Home. Masonic Memorial services will be there 8 p.m. SUnday. Services witll be 11 a.m. Monday in the funeral home, the Rev. David Barnard officiating. Commital services will be 11 a.m. Tuesday in the Mexico Village Cemetery, Mexico, N.Y. Memorials may be make to the Bath Volunteer Ambulance Corps.