Binding energies of carbonaceous overlayers on ruthenium were measured using angle-resolved XPS data and curve fitting procedures. A carbonaceous overlayer prepared by dehydrogenation of adsorbed ethylene at 750 K was disordered and had a binding energy of 285.0 eV. After annealing to 1300 K islands of azimuthally ordered graphite were formed with binding energy shifted to 285.6 eV.