Caltech students in Advanced Field and Structural Geology (Ge121a), Fall 1999, examine basalts in a quarry exposure in Arrastre Creek, west of the Old Woman Springs fault in the Mojave Desert. From left to right the students are: Kristine Nielson, Mike Oskin (partially hidden), Huirong Ai, Elisabeth Nadin, Bruce Hsu, Aron Meltzner.