original continuity Any archaeological deposit, as originally laid down, will be bounded by the edge of the basin of deposition, or will thin down to a feather edge. Therefore, if any edge of the deposit is exposed in a vertical plane view, a part of its original extent must have been removed by excavation or erosion: its continuity must be sought, or its absence explained. Law of stratigraphic succession Any given unit of archaeological stratification takes its place in the stratigraphic sequence of a site from its position between the undermost of all units which lie above it and the uppermost of all those units which lie below it and with which it has a physical contact, all other superpositional relationships being regarded as redundant. Law of original consolidation This law makes the distinction between architectural stratigraphy and all other types in regard to three criteria: When intact, architectural stratigraphy is of consolidated nature, as opposed to the loose or scattered below-ground remains. Erosion causes parts of buildings to become part of soil stratigraphy. Architectural stratigraphy is characterised by human intentionality, which is only seldom the case with below-ground strata. Gravity: architectural stratigraphy left in situ is pulled down by gravity, in combination with human or natural intervention, while below-ground stratigraphy is created by gravity. As a result, architectural stratigraphy scatters with time, the oldest parts being those which resisted the effect of time. In use In constructing a matrix, the latest contexts sit on top of the matrix and the earliest at the bottom with the lines that link them together representing direct stratigraphic contact (though note that though all stratigraphic relationships are physical, not all physical relationships are stratigraphic). The matrix thus demonstrates the temporal relationship between any two units of archaeological stratification. While excavating, it is best practice to compile the area and site stratigraphic matrices during the progress of an excavation through reference to both the drawn and written record. Regular daily checking of the record and the compilation of the matrix itself both help inform the individual archaeologist on the physical processes of site formation and highlight any areas where dubious relationships such as H relationships or loops in the recorded sequence may occur. Loops are sequences in the matrix that produce temporal anomalies so that the earliest context in a sequence of context appears to be later than the latest context by virtue of