The correlation between Bouguer gravity anomaly and depth to the 'Riel' reflecting horizon established in southern Alberta in the region around 113 °longitude and 51 °latitude is not substantiated on a smaller gravity anomaly further to the south. Only small variations in depth to the 'Riel' reflecting horizon occur and these do not correlate well with the gravity data. The reflecting horizons are continuous over distances of only a few kilometres. Model calculations of the reflecting zones based on an analysis of the variations in power spectra of the reflections indicate substantial changes in the layered reflecting zones over distances of the order of a few hundred metres. Some attempts at deconvolving the seismic data confirm that the prominent reflections are caused by rapid variations in reflection coefficients indicating finely layered zones a few hundred metres thick.