Evaluation of individual soil horizons and sequences of soil horizons in archaeological studies is critical to the correct and meaningful interpretation of archaeological context. We focus on the evaluation of soils in the stratigraphic framework of an archaeological site and offer a guide to assist in the interpretation of context of cultural materials in specific master horizons. In the North American Stratigraphic Code, the formal pedostratigraphic unit, the geosol, by definition requires being overlain by a formally defined lithostratigraphic or similar material unit. This criterion can rarely be met in shallow, mid-to-late Holocene settings. In addition, no subdivisions of the geosol are recognized, a problem at the scale of archaeological excavation. Chronostratigraphic and pedostratigraphic units are often confused in concept. The main distinction between these two, critical to archaeology, is in their boundaries and in the subdivision into smaller units. Boundaries of chronostratigraphic units are synchronous and form isochrons, whereas boundaries of pedostratigraphic units are time-transgressive. Subdivision of chronostratigraphic units results in subunits that represent shorter periods of time than the larger unit and that lie in temporal succession with each other (i.e., they follow the Law of Superposition). When a pedostratigraphic unit is subdivided, logically into soil horizons, the individual horizons are not separate from the whole soil, or from each other in a temporal framework. Each soil horizon has a unique set of properties and processes, and is separated in space, but not in time from adjacent horizons. The distinction between subdivision of chronostratigraphic and pedostratigraphic units is a fundamental difference between soils and sediments. The guide we present is based on pedogenic and geo-morphic processes, both past and contemporaneous, occurring in specific master horizons.