This box is all about the geology of the San Francisco Bay Area and Earth history. Students will learn about the rock cycle and the types of rocks that form under different conditions. Using this knowledge, students will investigate the rock layers exposed alongside the Caldecott Tunnel (Highway 24). Their explorations will reveal the geologic history of the San Francisco Bay area as it transitioned from ocean, to riverbed, to flood plain, to volcano, and then back to ocean again. In addition, students will research and create a timeline of life on the planet investigating the various life forms throughout the history of our planet and putting our own miniscule existence as human beings into the context of the enormity of Earth history.