Abstract: Disclosed herein is a device and method for correlating core sample zones with an actual subterranean depth. The disclosed device has a pair of independent distance measuring devices operably in communication with a core sample apparatus where a first distance measuring device measures the length of a core sample entering a core sampling tube and a second distance measuring device measures a drive depth of the core sampling tube entering into the ground. A processing unit is provided for correlating the two distances so as to allow a determination as to the actual depth below ground from where a given zone of the core sample is extracted.