Geologists have an interest in the structure and the history of the earth. a geologist can go back in time by drilling deep into the ground, retrieving a core sample, estimating the ages of the various layers, and examining the composition. a timeline can be built of the entire area from where the core sample was drilled. a geologist may retrieve several core samples to confirm the history of the earth's structure in that sampled area. mountains, lakes, and unstable ground can easily impede a simple random sampling of a desired geographical area, therefore what is the most realistic sampling method that represents the actual drillings, comparisons, and scientific examinations of several core samples within the same geographical area?