Abstract: Method and apparatus are disclosed for investigating lateral characteristics of an earth formation penetrated by a borehole. Substantially identical measurement transducers are mounted in a fixed separation, side-by-side relationship on a pad adapted for sidewall application. As a pad traverses the borehole, measurement signals are produced corresponding to the same formation investigation conducted along two side-by-side paths on the borehole wall. The signals are recorded and provide an indication of lateral changes between the side-by-side paths. By comparing the signals with varying depth displacements, the best likeness and corresponding displacement are determined and provided as an indication of lateral inclination of the formation. The best likeness indicates a lateral formation homogeneity characteristic and the displacement the inclination of the lateral characteristic between the side-by-side paths.