Samuel H. Jennings, age 79, of Lewisburg, formerly of Pocahontas County, died Thursday, April 20, 2000, at Greenbrier Valley Medical Center at Fairlea, after an extended illness.   Mr. Jennings was born April 14, 1921, in Pocahontas County, and was the son of the late Samuel Henry and Ethel Schoonover Jennings.  He was a graduate of Green Bank High School and was retired from the United States Forestry Service at Bartow, where he was a clerk and assistant business manager. He also served as volunteer fire dispatcher for Monongahela National Forest.  Mr. Jennings was a member of the Lions Club both at Durbin and Lewisburg since 1946, and was past president, secretary, tailtwister and zone chairman.  He was a member of the Old Stone Presbyterian Church at Lewisburg and was also a member of Liberty Presbyterian Church at Green Bank.   He was a member of the Riverside Lodge #124 at Cass, since 1951; the Charleston Valley of the Scottish Rite 32nd Degree Kooh; Bene Kedem Shrine in Charleston; Royal Arch Mason, Greenbrier Chapter #21; Knight Greenbrier Commandry #15; Royal Order of Scotland; and was a member of the Royal Order of Jesters Court #111, of Charleston. He was a WWII, US Army Veteran from 1943 to 1946 where he served in Japan and the Philippine Islands.   He is survived by two sisters, Alice Gwendolyn Ervine, of Summersville, and Ethel Virginia Spencer, of Dayton, Ohio. He was preceded in death by his wife and very close companion of 52 years, Ruth Beard Jennings, in 1996, who was a former first grade teacher at Bartow. They were married August 11, 1944. He was also preceded in death by one sister, Louise Osborne; and brothers, Lyle and Keith Jennings. Services were held Saturday at Arbovale Cemetery with the Rev. David Rittenhouse.