Fred R.Clark Sr.;86;of 217 Clark St.;Belle Vernon;died Thursday;Aug.1;1991;at 11 a.m.in the Jefferson Health Center. He was born in Belle Vernon on April 8;1905;a son of the late George H.and Ada May Smock Clark. Mr.Clark was a lifelong resident of Belle Vernon. He was a retired water well driller. In addition to his parents;he was preceded in death by two brothers;H.Ernest Clark and Ralph Clark. He is survived by his wife;Margaret Delansky Clark;a son;Fred R.Clark Jr.of Belle Vernon;two daughters;Mrs.John (Shirley) Demko of Belle Vernon and Mrs.Anthony (Marjorie) Apicerno of Harrisburg;10 grandchildren and 14 great-grandchildren. Friends will be received at the Ferguson Funeral Home Inc.;700 Broad Ave.;Belle Vernon;Friday from 2 to 4 and 7 to 9 p.m. Funeral services will be held in the funeral home on Saturday at 11 a.m.with pastor James D.Burton of the First Presbyterian Church officiating. Interment will be in Belle Vernon Cemetery. The Ferguson Funeral Home Inc.is in charge of the arrangements.