Tionesta area resident Harry Marshall was hurt in a traffic mishap, in central Clarion County.     But, there is no word that he needed any hospital treatment.     Marshall had been driving a vehicle on Guitonville Road (Route Three-Thousand-Four), at its intersection with Whitton Lane, in Green Township.     As the vehicle tried to go around a curve, it slid off of the road and went ino a ditch.     This mishap took place shortly before Eight Tuesday Evening.