evidence: At the base of the Tower, one will see the evidence of the changes it has undergone throughout its geologic history. Massive rocks, some large as a bus, form a 13-acre field. Predominantly around the west and south faces of the Tower, this field of giant rocks was created as pieces of the Tower weathered off and eroded down. [...] The west and south faces of the Tower are the most exposed to sunlight and storm systems. These forces also contribute to the weathering and erosion process. The sun's heat results in thermal expansion, causing the rocks to shift or crack over time. Rain, hail, and lightning all have gradual impacts to the Tower. Once the rocks have broken off, or weathered, from the Tower, erosion does the work of moving the giant boulders. Gravity is the primary force at work, pulling down loose rock. They may break again when impacting things or rolling, and today pieces of the Tower can be found over a quarter mile from the formation.