Neenach Volcano

The remnants of the western portion of the volcano are located in Pinnacles National Park (). The most prominent outcrops in the park (High Peaks, Balconies, Machete Ridge and other notable, but unnamed megaliths) consist primarily of eroded pyroclastic flows or air falls, including volcanic breccia, rhyolitic lava flows and volcanic tuff. Remnant andesite lava flows or dikes are also present at a few locations in the park, including the Tourist Trap climbing area and along the West Fork Chalone Creek. The park encompasses roughly 42 square miles and the Neenach Volcanics represent about 20 square miles of the total. == Neenach ==

The remnants of the eastern portion of the volcano, called the Neenach Formation, lie about 195 miles (314 kilometers) south of the western portion near Neenach, California. (). Satellite imagery reveals several areas of exposed rhyolitic tuff and lapilli tuff, a light green pyroclastic rock that also occurs in Pinnacles National Park and was used to construct the visitor center and other structures there. Although the entire formation appears to be on private property, a segment of the Pacific Crest Trail transects the Neenach from southwest to northeast, with trailheads at the intersection of Lancaster Road (California State Route 138) and 269th Street West and along Pine Canyon Road about 0.9 mile east of Horse Trail Campground, which is also on the PCT. == References ==