inventoried. The John Day River, which passes through the Sheep Rock Unit, is the longest undammed tributary of the Columbia River, although two Columbia River dams below the John Day River mouth impede migratory fish travel to some degree. Chinook salmon and steelhead pass through the monument on their way to and from upstream spawning beds and the Pacific Ocean. Species observed at the Sheep Rock Unit also include those able to tolerate warm summer river temperatures: bridgelip suckers, northern pikeminnow, redside shiners, and smallmouth bass. From October through June, when the water is cooler, Columbia River redband trout and sculpin are among species that move downriver through the park. The Park Service has removed or replaced irrigation diversions along the river or Rock Creek that formerly impeded fish movement, and it is restoring riparian vegetation such as black cottonwood trees that shade the water in summer and provide habitat for aquatic insects. Activities Entrance to the park and its visitor center, museums, and exhibits is free, and trails, overlooks, and picnic sites at all three units are open during daylight hours year-round. No food, lodging, or fuel is available in the park, and camping is not allowed. Hours of operation for the Cant Ranch and its cultural museum vary seasonally. The Thomas Condon Paleontology Center is open every day from 10 a.m. to 5 p.m except for federal holidays during the winter season from Veterans Day in November through Presidents' Day in February. Its amenities include a fossil museum, theater, education classroom, bookstore, restrooms, and drinking fountains. There is no cell phone or pay telephone service in the monument. Water taps at picnic areas are shut down in the colder months. The Sheep Rock Unit has eight trails ranging in length from at the Mascall Formation Overlook to at Blue Basin. Four trails of a quarter-mile to long cross parts of the Painted Hills Unit. At the Clarno Unit, three separate quarter-mile trails begin at a parking lot along Oregon Route 218, below the face of the Clarno Palisades. Many of the trails have interpretive signs about the history, geology, and fossils of the region, and three trails—Story in Stone at the Sheep Rock Unit, and Painted Cove and Leaf Hill at the Painted Hills Unit—are accessible by wheelchair. Visitors are asked to stay on the trails and off bare rock and hardpan to avoid damage to fossils and