Studies1 in thin YIG films, argon implanted, report that an amorphous layer is produced and a surface spinwave is generated at the perpendicular orientation. Earlier studies of YIG films have reported surface modes at the parallel orientation only.2 In this paper the effect of such an amorphous layer on the spinwave spectra was observed at 9 GHz as a function of temperature (from 20°−300°K) and orientation, and at 23 and 34 GHz as a function of orientation at room temperature. A critical angle is observed at all temperatures and frequencies. The deviations of the low order spinwave modes from a quadratic dependence and the presence of the surface mode in the perpendicular orientation are consistent with the amorphous layer having a larger magnetization than the bulk region of the film. As the temerpature is decreased, the localization of the surface mode is seen to go from 106 Oe at room temperature to 425 Oe at 85°K. This indicates that in this region the amorphous magnetization is increasing at a faster rate than the bulk magnetization as the temperature decreases. Below 85°K the trend is reversed.