A seismic refraction survey was undertaken on November 18-20, 1968 to determine the feasibility of using this geophysical method in determining the thickness of laterite deposits. The instrument used was a SEISMIC TIMER Model 117, manufactured by Dynametric Inc., U.S.A. It measures travel time of shallow and subsurface seismic shock waves initiated by hammer blows. The principle involved in the operation is that seismic wave velocities vary with the conducting layer. Velocities are faster in dense, solid materials than in loose materials of lighter density.