Answer:
The scientist is determining the relative age of the rock and the method is known as relative dating of rocks.
Step-by-step explanation:
The relative dating method is based on the fact that more older the rock layers, the more it would be deeper. The overlying layer of rock will be located in less deeper location, henceforth it would be less older rock layer. This method is mainly used by the scientists, for determining the age of the rocks or fossils embedded in it, before any absolute dating method like radioisotope dating of rocks is discovered.