The geologic record isn’t always “perfect.” But the imperfections give important clues, too. Unconformities are inconsistencies in the rock layers. They often show how erosion, uplift, sea level change and other processes shaped a landscape. There are different kinds of unconformities. An angular unconformity occurs when older rock layers are tilted, and then younger rocks form a horizontal layer above them. This indicates that deformation and erosion took place during a pause in sediment deposition. One angular unconformity is visible in the Grand Canyon. Which of the following is the best title for this passage?
(A) The Grand Canyon (B) Geology (C) Tilted Rocks (D) Unconformities