Ocean floor topography can be characterized as a signal related to lithospheric cooling and a residual; the residual can be further modeled by comparing the shape of its power spectrum with that of a fractal process. Power spectra of Seabeam profiles along a flowline in the South Atlantic are calculated; the data are resampled, pre-whitened by first differencing, tapered with a Hanning window, and passed to an FFT. The effects of the pre-whitening are removed and the spectra are smoothed. The spectra of ocean floor topographic residuals are curved (power increases less rapidly with increasing wavelength) at wavelengths greater than several 10's of kilometers and straight at shorter wavelengths. ¿ American Geophysical Union 1988