What are the study methods of archaeology? Information about the study of archaeologists and the methods they use?
Archaeologists work with a variety of purposes and techniques. One of the best ways to present the methods of archaeology is to describe a complete archaeological operation.
Organizing the Study.
In the 1940’s, Paul S. Martin, an archaeologist at the Field Museum in Chicago, became interested in an archaeologically unexplored area of the southwestern United States. He had «good reasons for believing that the remains of a little known and at that time undefined prehistoric culture would be most abundant in west central New Mexico. Accordingly, under the sponsorship of the Field Museum, he organized and led an expedition to the area. A preliminary survey had located one large site that seemed to be well worth excavating, and there were believed to be other sites in the vicinity. Thus Martin decided that the expedition would combine excavation and a more detailed archaeological survey.
The expedition consisted of Martin and a trained field assistant, a photographer, several student assistants, and a cook. Local men were to be hired to do the heavy digging. The first job was to build a field headquarters consisting of a bunkhouse, latrines, kitchen, living quarters, storeroom, laboratory, and photographic dark room. Next a tank for water storage was installed so that there would be water for washing, drinking, developing and printing photographs, and cleaning specimens. In this case, water to fill the storage tank had to be hauled from a well about half a mile away.
The Archaeological Survey.
The plan of the archaeological survey was to make an intensive search of an area of about two square miles in order to obtain a representative sample of the kinds of archaeological remains that existed in the region as a whole. The area to be covered by the survey was part of a large valley with two somewhat different topographical provinces. One was characterized by hills timbered with pine, cedar, juniper, and live-oak trees and by flat, broad valleys that were largely grassland.
The other province consisted of similarly wooded ridges and foothills with a network of shallow streams, springs, and dry washes. In either instance much of the area was covered by enough timber to make visibility difficult; thus the survey party found it necessary to use compass courses at selected intervals. These courses and measured intervals were then transferred to existing U.S. Geological Survey topographic maps.
The search was conducted on foot: the archaeologist, walking along his compass line, looked for evidences of past human occupancy of the area. In this instance three kinds of clues could be seen by a trained observer. First, there were clusters of flint chips or potsherds (small fragments of pottery). The stone chips, byproducts of the manufacture of stone tools, and the fragments of broken earthenware are among the signs that the archaeologist is trained to recognize as evidence of past human occupancy. Another clue consisted of shallow depressions, about 12 to 24 feet in diameter, which were best seen in early morning light when the length of the shadow thrown by an otherwise nearly imperceptible rim could be noticed. Such depressions were the remains of partly underground houses. The roof timbers had long since rotted away, and the pit foundations had been filled by natural flowing and shifting of surface soils.
Still another clue existed in the form of low mounds of rock overgrown with pines and junipers. These rock piles were the remains of the dry-laid masonry walls of small pueblos that had originally contained from two to twelve rooms. In some instances several clues might be found together; that is, the remains of a dwelling structure might be associated with surface finds of potsherds and flint chips or, on rare occasions, with finished artifacts such as a grinding stone or a flint knife. But, more often than not in this particular archaeological survey, the clues were distinctive and separate. When the survey was completed, the locations of the sites were placed on maps, the sites were classified as to types, and the pottery fragments, flint chips, and other artifacts were classified and analyzed. Finally, all the data were recorded and the records v^pre filed for future use.
Excavation and Mapping.
Meanwhile, the site that had been chosen for detailed examination was being excavated under the direction of Paul S. Martin, the leader of the expedition, and his assistant, Robert J. Braidwood. The site was a 2,000-year-old village of 20 or more pit houses (partly underground houses of round or oval outline with earth-covered roofs of poles and branches supported by posts). The village was situated on a gently sloping, well drained ridge extending outward from one of the foothills at the base of the San Francisco Mountains.
The field crew consisted of seven local men, four students, a surveyor-photographer, and Braidwood, who was in charge of the excavation. Work started at seven o’clock in the morning and stopped at half past four in the afternoon, with an hour and a half for lunch and rest at noon. All tools were brought by pickup truck from the expedition headquarters some three and a half miles away and were returned at night. Heavy digging equipment consisted of several large picks, axes, a crosscut saw, mattocks with the adze blade kept sharpened for dressing a vertical earth profile, a dozen light picks, and an equal number of light long-handled spades.
A wheelbarrow and a scoop and team of horses, rented from one of the local workmen, were used for moving earth away from the excavations. Light digging and cleaning equipment included small army-style entrenching mattocks, geologists’ hammers, a small army spade, kitchen spoons, whisk brooms and paint brushes, surveyors’ lining pins used as probes, grapefruit knives, and pointing trowels. Several tarpaulins were kept handy for use in eases where it was not desirable to have the soil dry quickly and harden, as, for example, in clearing out burials. Dirt from particularly productive areas was sieved. An ordinary spray, with plunger for compression and a carrying strap, was used, with water, to dampen the soil in order to increase the color contrast between undisturbed earth (called “sterile” because it contains no artifacts) and the dirt containing cultural materials. The student members of the expedition were given the responsibility of distributing the light and heavy tools and water containers in the morning and checking them in again at the end of the day’s work. The students also loaded the truck.
Each digging unit was equipped with one or more tight wooden fruit boxes for holding potsherds. At night the sherds were put in small cloth bags and tagged with their findspots, or exact proveniences, ready for washing, cataloging, and classification back at the expedition headquarters. As artifacts and related cultural remains were found, they were put in marked paper sacks; fragile or fragmentary pieces were wrapped in a cheap grade of tissue paper. Heavier stone artifacts were put in a special pile and returned to the camp laboratory as conditions warranted. At all times during the excavation of the site, every effort was made to maintain a high standard of neat and precise digging in order to ensure accuracy of records and counts of artifacts.
The actual methods of excavating the pit houses, according to Braidwood, were as follows: As the first step, lines for a straight trench about 1.5 meters (5 feet) wide were laid across a depression or an area suspected of being a pit house. Every attempt was made to lay the center of the trench through the middle of the depression. Then two workmen, picking back to back as closely as safety allowed, proceeded to dig downward in the trench for about half a meter (20 inches). If, at this depth, the dirt still had the blackened appearance of topsoil and | was yielding occasional potsherds and flecks of charcoal, then the probabilities were excellent that it was now “fill,” an accumulation of the debris of the earth roof of the original pit houses together with subsequently accumulated debris and humus. If, on the other hand, the depressed area was sterile, then this first operation in the center of the trench would encounter the orange-brown gumbo of the normal soil profile at much less than the half meter’s depth. In such an instance, 4 or 5 meters (about 10 to 16 feet) of the length of the trench might be dug down to the compact surface of this sterile gumbo, to determine by the profile whether the trench had crossed the center of the depression or whether any smaller architectural feature such as a surface house had caused the apparent depression. In the first case, however, with the trench still yielding fill at a half meter’s depth, the workmen were allowed to dig downward with care until the floor of the original substructure pit was reached. In every instance it was found that the ancient Indians had sunk their pits down into the oxidized and leached soil zone. Thus the surface of their original floor was differentiated from the accumulated fill by a change in color and density of the soils.
Once the presence and depth of the original floor had been ascertained, the center trench was continued out in both directions toward the rim of the depression, and the proper soil dump was started outside the anticipated area of excavation. In prolonging the trench both ways from the depth test in the center, the workmen were made to stay about 10 centimeters (4 inches, above the level of the floor. The final stage of the first operation ended when both ends of the central trench had made contact with the vertical wall of the pit. The vertical face of the pit-house wall, like the pit-house floor, showed an abrupt change in both color and density from the dark humuslike fill.
When the central or cross trench was finished, the encircling trench was begun. This was simply a tracing of the circuit of the vertical face or wall of the original pit, done with the light picks by flicking the fill away from the lighter-colored vertical face. The vertical wall showed the normal soil profile of gumbo and then oxidized and leached material below the topsoil. This trench needed to be no wider than convenience in picking, cleaning, and shoveling demanded, and was not dug deeper than 10 centimeters above the floor. When finished, this trench completely encircled the inner periphery of the pit house and also showed in profile the short entrance passage that usually was located at the east side. The earth fill from the entrance passage was easily recognized by the usual differences in soil color and texture and was removed by picking and shovelling.
At this stage of the excavation, the dumps were well established around the rim of the pit and were kept at least a pick handle’s length back from the edge so that the loose earth would not fall back into the excavation. At this point the archaeologist coulct clearly see the outline of the particular pit house being worked on. The outer wall of the pit was encircled by a trench, and another trench bisected the circle or roughly oval form. But still to be dug were two areas of fill shaped like half circles and the 10 centimeters of fill that had been left above the floor.
The next step in this excavating procedure was the removal of the remaining segments of fill within the pit down to the 10-centimeter level above the floor. This was done by removing layers 25 centimeters thick and saving all cultural materials layer by layer. When this operation was completed, the remaining 10 centimeters of fill over the floor was carefully excavated, using only light tools such as trowels. All potsherds, chips, artifacts, and objects of cultural significance were collected and labeled as coming from this particular provenience. Groups of stones and large stone artifacts were left in place. The various subfloor features, such as pits and post-holes, were outlined by digging them down several centimeters below the floor level. Then the floor was dampened by water from the portable sprayer to bring out the contents in soil colors, and the floor was carefully photographed.
The next operation was the removal of all the floor stones and artifacts and the removal of fill from all the subfloor features. This final digging was done with trowels, brushes, and other light tools. Along with the above activities, the final dressing of the pit house for mapping and photography was done. All vertical faces were checked for overhanging topsoil, roots were cut off flush with walls or floor, and large root butts and large natural stones of light color were painted with muddy water to reduce their contrast in the photographs. The earth dumps were dragged back with the team and scraper, and the surface of the ground about the pit-house rim was then cleaned by trowel. A directional arrow of fixed length was placed pointing north on the floor of the pit house, and a meterstick for scale was placed against the pit-house wall. Then a plan photograph was made of the house from a tower 20 feet (about 6 meters) high. The photograph was taken with a large-view camera at a time when light-and-shadow conditions were at their best. The pit house was then mapped in detail, using surveyors’ instruments, and the final notations were made.
All of the pit houses were excavated and mapped individually. Then a map of the entire site was made, showing the positions and pit shapes of all the houses in the village. At the end of the season all excavations were refilled with the team and scraper, and oats were planted on the loose soil to prevent erosion.
While the excavation crew was at work, other personnel at the expedition headquarters were carrying on important tasks. At the end of each day, for instance, the materials found at the dig were brought back to the expedition camp. At the dig these materials had been placed in sacks, each carefully marked with the provenience, or exact location, of the finds. The specially trained workers at the expedition headquarters washed, sorted, classified, counted, and recorded all the types and varieties of artifacts, potsherds, cultural remains, or other data of possible significance. Soil samples were studied. Maps, profile drawings, and field notes were checked against the actual digging operations and against one another to make certain there were no mistakes and that all the varying operations were as nearly perfect as possible.
Importance of Precise Techniques.
The account of the investigation of an Indian village has stressed the care taken at every step. Such elaborate care is essential because, once an archaeological site has been excavated, it is completely destroyed as a scientific document. The layers of artifacts have been removed, the relationships of features, structures, and artifacts no longer exist in the earth. Even if walls are left standing or are restored, the site is not the untouched document that it was prior to excavation. If a historian found a valuable document, read it, and then destroyed it, no other historian would be able to read the same document. Historians do not, of course, destroy documents; they preserve them in special libraries and archives. But since the archaeologist destroys his site as a document when he digs it, he must make every effort to measure and describe it in such a way that what was once in the earth is transferred to words, maps, drawings, and pictures on paper. In fact, if the archaeologist has done his work properly, it should be possible to put the site back together, with every object, soil type, and the like just as he found it. There is, of course, no reason for doing such a thing. This theoretical ideal is presented here only as an indication of the high standards of excavation technique required of a responsible archaeologist who realizes that he cannot avoid destroying his document as he investigates it.
When the excavation and all the other field operations have been finished, the expedition returns to its sponsoring institution, usually a museum or university. Here, in the laboratory, the analyses, comparative studies, and interpretations take place. For each three months of field work, about nine months of laboratory work is required to prepare a finished archaeological report. In the laboratory all of the excavated materials are further cleaned, mended, restored when necessary, and otherwise prepared for analysis. All of these materials were cataloged in the field, but if more elaborate cataloging is required, it is done in the laboratory. Then the artifacts and other cultural materials are analyzed and described and measured in terms of shape, size, composition; biological, physical, and chemical properties; and construction, function, and anything else that the archae^ ologist thinks might be a clue to past human history and culture. As we have said, the archaeologist works somewhat like a detective or® a technician in a crime laboratory. Often specialists from other fields of science are called in—a botanist, for example, to identify remains of plants. Finally, artifacts and other cultural materials are classified into types according to various systems that place like materials with like in the same class or grouping. For example, all stone tools made by one method may be grouped, and all pottery fragments with a characteristic design can be classified as a type.
As a methodological approach, typology varies greatly among archaeologists. The method may range from rather simple systems of grouping artifacts by material and design to sophisticated concepts supported by statistics and theories of probability. In its most simple form, a type is symbolic of its class and exhibits all of the attributes or characteristics that differentiate the type from all other types. When these types are sufficiently real and not imposed by the archaeologist, then the types represent formerly existing cultural realities, and the distinctions based on them can be interpreted in anthropological terms. That is, what the archaeologist concludes from studying a typical tool can be used as evidence of how an ancient group of people lived and worked. Most archaeologists nowadays describe their concepts of types and give the context or frame of reference within which they have used the particular concept. When dealing with types that represent formerly existing cultural realities, the archaeologist must of necessity pay more attention to the data of ethnology and to the establishment of function for his types of artifacts. He notes clusters of types and aims his research at definition of different operational subsystems of the total cultural system he is studying. He distinguishes the types and type clusters that have their primary functional context in the interaction of culture and physical environment from those that have their primary functional context in the social subsystems or the ideological subsystem.
Types of Pottery.
The concept of type is and has been applied to artifacts of any kind, from crude stone tools, harpoon heads, fishhooks, and milled grains to pyramids. The most common category of types, however, relates to pottery. Pottery is one of the most useful items among the unintentional records left by past peoples. Although a pottery vessel may break into a hundred or more pieces, or sherds (also shards) as they are called by archaeologists, each sherd is exceedingly durable and will remain intact in the earth for thousands of years. Moreover, pottery was easily made, easily broken, and used in abundance. Therefore, if an ancient culture used pottery, it usually left great quantities of sherds. From these sherds the whole vessels can be reconstructed. Except for museum exhibitions or illustrations in reports, however, this is not done. The archaeologist has had so much experience with pottery that he can tell vessel shapes, sizes, and ornamentation from the sherds. The sherds are classified into types. If this is done well enough, the types represent classes of vessels made by one group of people at one given place at one given time and for one purpose.
A knowledge of the purpose or function of pottery types can be obtained from distribution and cultural context within an archaeological site or sites. For instance, sherds of ceramic types found in hearths and cooking areas came from pots used in the storage, preparation, and serving of food. These pottery types, then, represent the technological and social subsystems of the extinct culture. Similarly, types of storage jars found at the site of a sunken ship are indicative of former trade in wines or oils and are a component of the technological and social subsystem of the extinct culture. Those pottery types found only in shrines, temples, and burial places are artifacts of religion and are a part of the ideological subsystem of an extinct culture.
Knowing how pottery was made can provide evidence on how the people of a given culture lived. In some cultures the pottery was made by hand without the use of a wheel or molds. This manufacturing process represents the technological level of the culture. At the same time the manufacturing process gives insight into the social structure. For instance, among uncivilized peoples whose culture was based on the sowing and harvesting of grain, descent may have been reckoned in the female line. Hence a number of related women and their husbands lived in one large house or cluster of houses owned by their lineage or clan. Pottery making usually was a part of the labor of such a group of women, and each woman learned to make pottery. A girl learning to make pottery by hand was taught by or under the observation of a number of women, her mother, sisters, aunts, and grandmother. There was a well established cultural pattern or ideal which the young beginning potter followed if she wanted the approval of her peers. The pottery representative of such a culture is exceedingly uniform in shape, size, and decoration. It generally is restricted to a very few types that were made in relatively large quantities. The archaeologist, after classifying the pottery types from such an extinct culture, knows or suspects the kind of social subsystem manifested by his artifacts. Then he looks for additional data among his archaeological records.
When studying a more elaborate level of culture, the archaeologist may find pottery that was made on a wheel and was stamped with the name or seal of the manufacturer. Such pottery is evidence that a people had reached an early form of civilization, with a social structure that included crafts and guilds. In studying the same kind of culture the archaeologist may find certain pottery types only in temples or other sacred places. With luck he might discover that such pottery was made only at the residences of the priests of the temples. He would then be justified in making the inference that the manufacture of this pottery as well as its use was regulated by religious beliefs and practices. Thus he would learn something about the ideological subsystem of this particular culture.
After all the laboratory studies have been completed, the archaeologist writes his report, usually intended for publication. The purpose of this report is to tell what the archaeologist did, present the facts he found and the concepts he used in classifying and analyzing his data, and tell what conclusions he reached. The archaeologist describes his site and how he excavated it. In this section of the report he uses pictures, drawings, site plans, maps, and profile drawings showing stratigraphy, construction, or soil differences. All photographs, maps, and drawings have to be clear and of a high professional quality. The archaeologist also describes and illustrates by drawings and photographs the classes and types of artifacts and other cultural materials found in his excavations. He explains his systems of classification and typology. In other sections of his report the archaeologist makes comparisons and contrasts with related archaeological phenomena. Finally, he presents his interpretations and conclusions. The finished report also includes a bibliography and usually an index.
The finished report is published by a museum or a university or some other nonprofit institution. Although published archaeological reports and monographs might be called the backbone of archaeology, they are expensive to publish and have to be subsidized by non-profit-making institutions. Commercial publishers are reluctant to publish such reports because they would not sell enough to make a profit. The kinds of archaeological books produced by commercial publishers, except for textbooks used in teaching, are for popular consumption and are of little or no use to archaeologists. The works upon which the discipline depends are usually published in editions of a few thousand copies or less and are distributed to scholarly libraries, museums, universities, scientific and other scholarly institutions, and archaeologists all over the world.