terminates at Canyon View Park in Aliso Viejo. The Aliso Creek Trail continues north along the creek towards Laguna Hills as a paved walking/biking path. The more enclosed and shaded Wood Canyon is a popular location for horseback riding; the hills bordering Wood Canyon include many mountain biking paths, such as the Mathis Canyon and Rock-It trails, ranging in difficulty from beginner to advanced. Many of the names for smaller trails in the park are from the Acjachemen language, including Aswut ("golden eagle"), Toovet ("brush rabbit"), Alwut ("crow") and Hunwut ("black bear"). Dripping Cave is a popular beginner's hike and was once used as a hideout by local cattle and stagecoach thieves during the 1800s. The Aliso Summit and West Ridge trails hug the ridge lines on the park's eastern and western boundaries, respectively. Geology Aliso Canyon began forming about 1.2 million years ago, as Aliso Creek carved its way through the hills at the same time the hills experienced geological uplift. During the pluvial Ice Age, ending about 10,000 years ago, Orange County had a much wetter climate and sea levels were lower; the valley is a relic of a time when much more water flowed through Aliso Creek as it cut its way to the sea. At the end of the Ice Age sea levels rose, backfilling the canyon and creating a shallow fjord. Sediment deposited by Aliso Creek slowly filled the canyon to depths of and created the flat valley floor seen today. The creek remains as an underfit stream whose present size, in today's semiarid climate, appears too small to have cut the canyon through which it flows. The San Joaquin Hills consist of marine sedimentary rock that originally lay at the bottom of the Pacific Ocean before being uplifted above sea level. As the creek cut through the hills it exposed strata of the Monterey Formation dating to the Miocene (5-23 million years ago) and the Eocene (34–56 million years ago). Limestone outcrops in the northeast section of the park, part of the Pecten Reef, have yielded thousands of fossils including Miocene dolphin and whales, preserved invertebrates, plankton, bryozoa, and red, blue and brown algae. Much of the scientific understanding for evolution, paleoenvironments and paleoclimates during the Miocene period in Orange County is based on the specimens collected from the Pecten Reef. Ecology The plant and animal species in the park are split between three