One man was killed and a local doctor critically injured Tuesday morning in a head-on crash atop Harrison Ferry Mountain in neighboring Van Buren County.The fatally injured driver has been identified as Lucas Lopez Ramundo, 37, of Nashville. The other driver, Dr. June McMillin, 64, of Ringgold, Ga., has been taken to Erlanger Medical Center in Chattanooga for treatment of serious injuries.The wreck happened shortly after dawn Tuesday morning near the one-mile marker on Highway 8 atop Harrison Ferry Mountain in Van Buren County. According to Highway Patrolman Ronnie Simmons, Ramundo was traveling southbound in his 1998 Saturn, away from McMinnville, heading toward a construction job in Dunlap when his vehicle slammed head-on with the northbound 2013 Lexus driven by Dr. McMillin.