The Geologic Column
The Geologic Column is a concept encompassing the vertical distribution of rocks worldwide. While scientists may debate the meaning of the Column, and argue about details, no informed individual can doubt the existence of the Column. The complete Geological Column is a theoretical construct encompassing all of the sediments deposited through all of the time sediments have been on the earth. While the column per se is a theoretical construct, it is sampled by the physical reality of the layers of rock found on the surface of the earth at any given locality. The Column does not directly tell time, but clearly if one layer lies above another layer, the underlying sediments must have been deposited earlier in time than the overlying sediments, barring tectonic overturning. Thus the column give a general direction to time (upward = closer to the present).
The Fossil Record, a related concept, encompasses all of the fossils represented in the Geologic Column. Fossils are found in the rock layers in an easily recognizable and reliable pattern, worldwide. These fossils also give a general order to the Geologic Column, but like the rock layers, do not themselves directly address the issue of time or the concept of evolution. Elsewhere on this site these issues are dealt with in greater detail.