A brief description of the volcanic rocks that make touring Lake County California unique. Once Lake County was unwanted property and now has become an outdoor classroom for schools and universities. Take a tour around Clear Lake in Northern California from the comfort of your vehicle or armchair to follow the landscape as it migrated from the ocean floor, collided with the San Andreas Fault and the Mendocino Triple Junction. Learn about the formation of Mt. Konocti, land formations, fault lines, ancient lakebeds, lake sediments. and more explained with maps, charts, and photos. Lake County emerged out of the ocean as young, unstable graywacke clays during 80-160 million years ago. The force of subduction, the Pacific Ocean Plate under the North American Plate, created thrust faulting scraping the deep-sea sediments onto the shore, causing the continent to overlap, and lift to create terraces. This marine collection became the groundwork of the Lake County Franciscan Mélange or Complex making up 80% of Lake and Mendocino Counties, as seen in the entire California coastal mountains and ranges.This mélange is approximately 70 miles from the coast to the mountains west of the Sacramento Valley. Three north-south trending belts have been designated; Coastal, Central (from the Ukiah Valley to Clear Lake, west side) and Eastern (north/east side of Clear Lake to Wilbur Springs), which gives you an idea of what was, what is and what will be as subduction on the coast ceases.