"Many of the stories of San Diego's prehistoric landscapes and life are captured and held in the sedimentary rocks and fossils of the region. Landforms have risen and fallen, sea levels have risen and fallen, species have risen and fallen, climates have warmed and cooled during the past 150 million years. No one is better qualified to tell these exciting tales of San Diego's prehistory than earth scientist Pat Abbott"-- Provided by publisher. Dr. Patrick L. Abbott is Professor Emeritus of Geology in the Department of Earth and Environmental Sciences at San Diego State University. For decades, along with his students and colleagues, they have studied the sedimentary rocks of the region. He is a popular lecturer in university auditoriums and on Smithsonian Journeys all around the world. Abbott is often seen on TV news programs and TV series explain how the Earth works. The walk begins along the towering cliffs cut by innumerable ocean waves (Figure 5.29). Near the base of the cliffs are greenish mudstone beds of the lagoonal Delmar Formation. They alternate with and are overlain by the orangish sandstones of the coastal tidal-flat deposits of the Torrey Formation (Figure 5.29). If seaward tidal flat deposits (Torrey Sandstone) lie on top of landward lagoonal sedimentary rocks (Delmar Formation), was sea level rising or falling? Stop and consider this question in three dimensions (try using your hands to model the scenario). This shows that during middle Eocene time, relative sea level rose (See Figure 5.3). [page 67, 68]