Archaeological Excavation Method Innovated by Dr. Edward C. Harris In The Exploration of Archaeological Heritage
There are two important elements of history. These are – (1) written elements and (2) unwritten elements. The written elements of history are successively recorded in books. And the unwritten elements of history are artefacts or antiquities, which are scattered in different geographical locations of the world. Exploration and research of artefacts and antiquities to verify the authenticity of the written elements of history, to enrich the history and to know the ancient civilization is very important. And an important means of exploring and uncovering artifacts or antiquities is archaeological excavation. Archaeologists in different countries adopt different methods for leading archaeological excavations. The method innovated by Sir Robert Eric Mortimer Wheeler and Dr. Edward C. Harris of them is particularly noteworthy. Present-day’s archaeologists are more interested in scientific archaeological excavation and in simply analysing and interpreting the data explored and recorded during archaeological excavations. The Harris Matrix innovated by Dr. Edward C. Harris is a more scientific and understandable method for archaeological excavations, which is also known as the Unit method. And for this reason, the method innovated by Dr. Harris is beginning to gain an importance among archaeologists. In this article, an attempt is to present archaeological excavation and field level data recording adopting the Harris Matrix method, and the simple interpretation and analysis by using Harris Matrix Composer (HMC).
Harris Matrix: The Harris Matrix is a method of representing the stratigraphy of archaeological excavations innovated by Dr. Edward C. Harris in 1973. The stratigraphic relationships between units of strata explored in archaeological excavation are represented through a sequence diagram in the Harris matrix method. A Harris matrix is a diagrammatic representation of the relative event calendar of an archaeological site. Actually, Harris Matrix is a standard method for analysing and interpreting the stratigraphic relationships of an archaeological site.
Strati-graphic Recording: Each event or stratum or context (such as surface, soil layers, architectural evidences like walls, pavements, etc.) in the archaeological site unearthed during archaeological excavation are recorded with separate units or numbers (1, 2, 3 ….) in a notebook or form. Each unit or context is separately shown by drawing a boundary polygon during recording in a notebook or form. A stratigraphic diagram of the archaeological site is represented with description by interpreting the relative position of each unit or context from the preliminary observations and drawings during the excavation.
It should be noted that, the direction especially the north line and the elevation (altitude) of the archaeological site which selected are determined at the beginning of the excavation. After that, the preliminary field plan of the archaeological site is prepared for excavation by dividing into squares or grids of specific measurements (6 meters x 6 meters or 5 meters x 5 meters etc.). Archaeological excavation work is easily conducted and controlled according to squares or grids divided in plan.
How to record archaeological data from top to bottom of each square or grid at an archaeological site by using the Harris Matrix method during excavation, it is represented with the following figure as an example.
Note that the topmost context or layer in Figure – 1 above is recorded by marking with unit 1. After removing the layer of contextual unit 1, another context or layer of different properties is found below, which is recorded by marking with unit 2. After removing the layer of contextual unit 2, three contexts or layers of distinct properties are found below, which are recorded by marking with units 3, 4 (wall) and 5. Layers of contextual units 3 and 5 have different colours and properties. Layers of contextual units 3 and 5 may be contemporary (same time events) for positional reasons. However, Layers of the contextual units 3 and 5 are not contemporary events of the wall ruins of the contextual unit 4. After removing the contextual unit 5, a separate contextual unit 8 (floor) is found below. Unit 4 (wall) is directly connected to the unit 8 (floor). However, according to the sequence of construction work, it is more likely that the unit 4 (wall) first and then the unit 8 (floor) are constructed. A different context below the units of 3 and 8 (floor) and on either side of the unit 4 (wall) is found, which is recorded by marking with the unit 6 (earth filling). After the work of unit 4 (wall), the trench is filled with the layer of the unit 6. Before this filling, a trench is cut for the work of unit 4 (wall) at this place. And the cut is marked with the unit 7. The unit 7 (cut) is an event, but not a physical layer. The units of 9 and 10 are homogeneous with the same characteristics. But The units of 9 and 10 are separated due to cut by unit 7. The units of 9 and 10 may be equivalent in terms of characteristics and position. The unit 11 (floor) is found below the unit 10 and the unit 12 (floor) is also available below the unit 9. The units 11 and 12 are separated due to cut by unit 7 though they have the same floor. The units 11 and 12 are positioned on the contextual unit 13.
Harris Matrix Composer and its explanation: As per figure 1 and above-mentioned description, the stratificational matrix or chronological design or events sequence is shown as follows in figure 2. A stratificational matrix or chronological design may be done by hand, or using software called Harris Matrix Composer. Below is a series of explanations of this matrix.
The contextual unit 1 is the layer of the latest event. So this contextual unit is shown at the top of the matrix or events sequence. Below that are the unit 2. Here, unit 2 is the layer of event occurring before topmost unit 1. For that, the unit 2 is shown after the unit 1 of the matrix. The Units 3 and 5 are shown separately under the same level under the unit 2. Because units 3 and 5 have different colours and characteristics, but may be contemporary in terms of location. The Unit 8 (floor) is shown under the unit 5. Here, the unit 8 is the architectural floor of the event that occurred before the unit 5. Before the unit 8, the earth filling of the unit 6 is done. So, the unit 6 is shown after the unit 4 in matrix. A wall of the unit 4 is built before the filling of the unit 6. Here, the unit 4 is an architectural wall relic of an event that preceded the unit 6. So, the unit 4 are shown after the unit 6 in the matrix. Before building the architectural wall of unit 4, the cutting work of the unit 7 is done to make a trench. While trenching, the unit 7 (cut) intersects the units 9 and 10, and 11 (floor) and 12 (floor). In this regard, the unit 7 (cut) is a new event compared to the contextual unit 9 and 10, and 11 (floor) and 12 (floor). So, the unit 7 after the unit 4 in matrix, and the units 9 and 10 after the unit 7 are shown side by side. Because the units 9 and 10 with the same characteristic layers may be contemporary in the aspect of location. The location of the unit 11(floor) is below the unit 10 and the unit 12 (floor) is below the unit 9 which are easily seen, that means two layers of units 10 and 9 on the floor of units 11 and 12 are created. Because of this, the relatively old event of the units of 11 (floor) and 12 (floor) is shown on the units 9 and 10 in the matrix. The layer of unit 13 intersected by 7 (cut) is below the units 11 (floor) and 12 (floor). Unit 13, usually the lowest layer, is shown at the bottom of the matrix.
During archaeological excavation, it is necessary to identify the layers with care in each excavation trench and record them with marking units, similarly, small and large artefacts found in each layer should be collected and sampled separately according to the unit. By this, comparative analysis and absolute dating/analysis of small and large artefacts and samples collected from each layer may be done. As a result, the actual period, cultural history and architectural features of any archaeological site may easily be known. [Md Shahin Alam]
Reference: C. Traxler & W. Neubauer, THE HARRIS MATRIX COMPOSER STRATIGRAPHY – A NEW TOOL TO MANAGE ARCHAEOLOGICAL, Vienna, Austria.