Where does facies collide?

In geology a facies is a body of rock with a distinct combination of features, such as rock type, sedimentary structures, and fossils, that records the environment in which it was deposited. Amanz Gressly introduced the term in his 1838 Observations géologiques sur le Jura Soleurois, using it for the lateral changes he traced within rock layers of the same age across the Jura mountains. Middleton's 1973 account of Walther's law later formalized how facies that sit side by side in an environment come to be stacked one above another as that environment shifts over time. Here the referent is a physical package of sediment or rock, not a face on a patient or a set of tools left by a culture.[1][2]

Unit

One mappable rock body, distinguished by its rock type and fossils and tied to a depositional setting

Recovery means

Not applicable

Measured by

Described in outcrop and core by rock type, sedimentary structures, grain size, and fossil content, then traced laterally and vertically through a succession

In medicine a facies is a person's overall facial appearance when it forms a recognizable pattern that points to a disease or syndrome. The oldest example is the facies Hippocratica, the pinched, hollow face of a gravely ill patient described in the Hippocratic Prognostic around 400 BCE; clinical genetics later extended the idea to the characteristic faces of inherited syndromes, and Allanson and colleagues' 2009 Elements of morphology set out standard terms for describing the head and face. Here the referent is the living human face read as a single diagnostic pattern, not a mass of rock or a kit of ancient tools.[3][4]

Unit

One patient's whole facial appearance, read as a single diagnostic pattern rather than one isolated feature

Recovery means

Not applicable

Measured by

Assessed by clinical inspection using standardized descriptive terms, and increasingly by facial measurements and image analysis

In archaeology a facies is a recurring assemblage of artifacts that marks a variant or phase within a larger culture or sequence. François Bordes used the term this way in his 1961 Mousterian Cultures in France, dividing the Middle Palaeolithic Mousterian into several facies set apart by the differing proportions of stone tool types. The label was borrowed from geology, where a facies likewise names a distinct unit within a sequence, and archaeologists still debate whether such facies reflect separate groups, activities, or dates. Here the referent is a pattern in human material culture, not a rock unit or a clinical facial appearance.[5]

Unit

One recurring assemblage of artifact types, treated as a variant within a culture or sequence

Recovery means

Not applicable

Measured by

Defined by the relative frequencies of tool types across assemblages, then compared within and between sites and layers