Occasionally you will uncover archaeological features such as pits and postholes. In this case, please refer to our separate ‘Guide to Excavating Archaeological Features’ and complete the relevant context fill and cut sheets. Section Drawing. A test pit section drawing is a drawing of one of the sides (vertical profiles) of the test pit. Since the purpose of a grid reference on the Context Record Sheet is to locate the context, a co-ordinate to the nearest 10m square should suffice. Co-ordinates relate to the southwest corner of a site-specific or OS related 10m square. Depending on the expected size and spread of the excavation, more precise coordinates may be required. What Is the Harris Matrix? As Professor Gavin Lucas suggested in his 2001 book, Critical Approaches to Fieldwork, the Harris Matrix and its associated concepts changed the paradigm of archaeological stratigraphy from a reliance on one-dimensional physical sections, or profiles, to the four dimensions (three physical ones of depth and area, plus relative time) of the stratigraphic sequence. The term context is also used by North American historical archaeologists as another name for archaeological layer. See Archaeological layer. Context sheets: Forms used by historical archaeologists to record information on different contexts or layers within an archaeological excavation. The historic context will also be useful to historians and architectural historians evaluating built environment properties. A Historical Context and Archaeological Research Design for Work Camp Properties in California. The fourth of several Caltrans efforts to improve the quality of historical archaeological studies in California.