Geomorphology is the study of the evolution of landforms. Analysis of surficial deposits provides much of the evidence for changes in landforms over time. These deposits may be residual materials, formed in place by weathering of underlying formations, or may have been formed elsewhere and then transported by wind, water, or humans to their present site of deposition. They include both sediments and soils, which are commonly confused in the field although each originates by different processes and each yields different kinds of information. Both geomorphology and surficial deposits are the principal subjects of several other publications and will not be covered in great detail here. This book aims to cover in more detail fields that are universally acknowledged to be important for archaeology but are generally ignored in the "geoarchaeology" literature. Those seeking more information on geomorphology and surficial deposits should refer to other publications. The kind and amount of surficial materials change with the changing land surface and climatic conditions and so offer the best evidence regarding the evolution of the landscape. An understanding of these changes on a site will allow a re-creation of the paleoenvironment at the time of occupation and a modeling of the prehistoric land-use patterns. Archaeological exploration in an area is facilitated by first pinpointing desirable habitation sites of the time and then targeting these sites for geophysical prospecting. After a site has been discovered, geophysical and geomorphic-sedimentologic information can help develop excavation strategies. Such information commonly allows a better idea of the distribution and nature of buried artifacts and may explain anomalous surficial redistribution of artifacts, for example, by downslope wash or sediment burial. The first study in a new area proposed for any detailed archaeological work should be geomorphic-surficial geology. It can be carried out in three distinct phases:1. Geomorphic mapping affords meaningful descriptions of the landforms, drainage patterns, surficial deposits, tectonic features, and any active geomorphological processes. 2. The erosional processes that carved the landforms—including soil formation, sediment removal or deposition, and tectonic uplift—are documented.