Bernal Heights Park

You are standing at the base of a significant geologic feature. Bernal Heights Park sits atop a massive formation of radiolarian chert, a hard, silica-rich rock composed of the microscopic shells of ancient marine organisms. This bedrock formed millions of years ago through the intense pressure of the Pacific and North American plates converging. When the 1906 earthquake struck San Francisco, this stable foundation saved many homes in the immediate vicinity from the destruction that leveled neighborhoods built on softer, unstable landfill.