Rock! Pattern! Systems! takes young geologists on a dramatic trek to the Point Bonita Lighthouse, the first place in California where scientists produced a detailed geologic map. Through both individual and small group work, students use copies of the first complete world map of the ocean floor to hone their powers of observation and find patterns in seafloor mountain ranges. A close read of a short biography of the mapmakers offers context for the 3 decade struggle to produce and publish a map that changed how we think about land and sea. At Point Bonita, students investigate seafloor rocks along the trail and pose information questions and questions for deeper meaning as they construct their own understanding of the importance of accurate data in creating new scientific knowledge.