Experiments have been undertaken to determine the feasibility of finding the location of the atoms of a pseudomorphic monatomic layer of silver on a palladium substrate. 200 keV He++ions are scattered off the palladium substrate before and after coating with an epitaxial silver film, the direction of incidence being along the <100> and <110> crystal directions, so that the backscattered yield is reduced by channeling of the He ions. Silver atoms that are aligned with atomic rows along the direction of incidence do not increase the yield of ions backscattered off the surface, whereas atoms that are interstitial to the atomic rows of the substrate do increase the vield. It is concluded that the technique is useful, particularly as an adjunct to LEED and Auger spectroscopy, in the study of film structure.