Clark Morrell Mathis, Sr., age 59, of Crossville, passed away April 7, 2018 at home surrounded by family and close friends. He passed away after a battle with a brain tumor. Clark had his Ph.D. in psychology and worked at Hilltoppers. He is survived by his wife: Susan (Weismuller) Mathis; sons: Aden and Clark Jr. (CJ); mother-in-law: Gladys Weismuller; sister: Kathleen Fischer of Nevada; and brother: William Mathis of New Jersey. Clark requested no service or flowers. Anyone who would like to remember him can donate to the savings account at Crossville First National Bank listed as “Susan Mathis to benefit Clark Mathis.” This account will be used for school expenses for his sons and medical expenses. The family would like to give a special thanks for the compassion and gentle care to Cancer Treatment Centers of America, Tulsa, Cumberland County Hospice, and Dr. Stephen Pribanich.