This document discusses crustal deformation and geologic structures. It describes the different types of stresses that cause deformation, including compressional, tensional, and shear stresses associated with convergent, divergent, and transform plate boundaries. It also explains how rocks deform through folding, faulting, and fracturing in response to these stresses. Specific structures covered include folds like anticlines and synclines, as well as normal, reverse, thrust, and strike-slip faults. The document concludes by discussing how geologists measure and map the orientation of rock layers and faults.