Laboratory experiments have been carried out to investigate underwater sound propagation over a sloping bottom which can support shear. The model of the seafloor consisted of a sediment layer (modeled experimentally by epoxy) over a hard substrate made of concrete. The sound field was measured in both the across slope and downslope directions for various frequencies and bottom slopes. The experimental results have been compared with a new source image theory for sound propagation in an ocean wedge with an elastic (shear supporting) bottom and have shown very good agreement for both downslope and across slope propagation. In particular the effect of shear waves on across slope propagation has been demonstrated both theoretically and experimentally. Further, the effect of a sediment layer overlying a semi-infinite substrate has been successfully incorporated into the source image theory for comparison with the experimental measurements.