Knowing the geology of Golden Spike National Historic Site enhances one's understanding of the unique relationship between geology and the environment. Geology provides the foundation of the entire ecosystem. Surface exposures in Golden Spike consist primarily of rocks from the Devonian, Mississippian, Pennsylvanian, Permian, and Tertiary ages. Vast unconsolidated Quaternary deposits overlay these units. Detailed geologic information helps determine the history of Golden Spike National Historic Site and helps managers preserve its present resources.