A well log obtained with an arrangement of electrodes similar to a miniature laterolog but disposed in concentric fashion in an insulating pad. The current from a central electrode is focused and flows out in a pattern that resembles the shape of a trumpet. As in the microlog, the electrodes are mounted on a pad that is held against the wall of the hole by springs. The microlaterolog serves a purpose similar to that of a microlog, investigating only a small volume of rock immediately adjacent to the hole.