The characteristics of an axisymmetric flame propagating over a thermally thick fuel bed of polymethyl methacrylate have been studied. For a pyrolysis region diameterdp> 5 cm, the flame propagation rate is constant atV= 0.0050 cm/sec. The mass loss rate has been measured as a function of flame size and compared with results for pool burning. The measured surface temperature profile in the near field (0.4 cm) ahead of the flame has been found to be independent of flame size and to give a ratio of preheat distance to flame radius of curvature which is much less than one. Radiation measurements from the flame to the fuel surface ahead of the flame have been made and are shown to account for the slow temperature rise at distances greater than 0.4 cm ahead of the flame. Fordp> 2.7 cm the flame oscillates and photographic sequences showing the development of the flame over an oscillation cycle are given.