We report surface compositions of the 4H-SiC(000 (1) over bar) C-face and 4H-SiC (0001) Si-face over the temperature range 300 to 1400 K, studied by Auger electron spectroscopy (AES), energy loss spectroscopy (ELS) and quadrupole mass spectroscopy (QMS). Below 800 K, no significant changes in surface composition are observed. Between 800 K and 1200 K, silicon preferentially volatilizes, leaving a slightly graphitized surface. Above 1200 K, preferential volatility of silicon results in a heavily graphitized surface. The thickness of the graphitized layer is greatest on the 4H-SiC(000 (1) over bar) C-face surface (similar to 8 Angstrom @ 1400 K). Results are compared with earlier work involving the polar faces of 6H-SiC.