When a site like the Palace of Minos at Knossos or the city of Harappā in Pakistan has been excavated, and the excavations are over, the excavator and the antiquities service of the country concerned have to face the problem of what to do with the excavated structures. Should they be covered in again, or should they be preserved for posterity, and if preserved, what degree of conservation and restoration is permissible? This is the same kind of problem that arises in connection with the removal of antiquities from their homeland to foreign museums, and there is no generally accepted answer to it. These problems remain to beset archaeology: should Sir Arthur Evans have reconstructed the Palace of Minos at Knossos? Should the art treasures of ancient Greece and Egypt, now in western European museums, be returned? There is no simple, straightforward, overall answer to these difficult questions. Underwater archaeology
Underwater archaeology is a branch of reconnaissance and excavation that has been developed only during the 20th century. It involves the same techniques of observation, discovery, and recording that are the basis of archaeology on land, but adapted to the special conditions of working underwater. It is obvious that no archaeologist working on submarine sites can get far unless he is trained as a diver. Helmeted sponge divers have made most of the important archaeological discoveries in the Mediterranean. The French scientist Jacques-Yves Cousteau developed the self-contained breathing apparatus known as the scuba, of which the most commonly used type is the aqualung. Cousteau’s work at Le Grand Congloué near Marseille was a pioneer underwater excavation, as was the work of the Americans Peter Throckmorton and George Bass off the coast of southern Turkey. In 1958 Throckmorton found a graveyard of ancient ships at Yassı Ada and then discovered the oldest shipwreck ever recorded, at Cape Gelidonya—a Bronze Age shipwreck of the 14th century bce. George Bass of the University of Pennsylvania worked on a Byzantine wreck at Yassı Ada from 1961 onward, developing the mapping of wrecks photogrammetrically with stereophotographs and using a two-man submarine, the “Asherah,” launched in 1964. The “Asherah” was the first submarine ever built for archaeological investigation.
Interpretation
Excavation often seems to the general public the main and certainly the most glamorous aspect of archaeology; but fieldwork and excavation represent only a part of the archaeologist’s work. The other part is the interpretation in cultural and historical contexts of the facts established—by chance, by fieldwork, and by digging—about the material remains of man’s past. This task of interpretation has five main aspects. Classification and analysis
The first concern is the accurate and exact description of all the artifacts concerned. Classification and description are essential to all archaeological work, and, as in botany and zoology, the first requirement is a good and objective taxonomy. Second, there is a need for interpretive analysis of the material from which artifacts were made. This is something that the archaeologist himself is rarely equipped to do; he has to rely on colleagues specializing in geology, petrology (analysis of rocks), and metallurgy. In the early 1920s, H.H. Thomas of the Geological Survey of Great Britain was able to show that stones used in the construction of Stonehenge (a prehistoric construction on Salisbury Plain in southern England) had come from the Prescelly Mountains of north Pembrokeshire; and he established as a fact of prehistory that over 4,000 years ago these large stones had been transported 200 miles from west Wales to Salisbury Plain. Detailed petrological analysis of the material of Neolithic polished stone axes have enabled archaeologists to establish the location of prehistoric ax factories and trade routes. It is also now possible, entirely on a petrological basis, to study the prehistoric distribution of obsidian (a volcanic glass used to make primitive tools).
In the third place, the archaeologist, having dealt with the material of his artifacts by classification and taxonomy, and with its physical nature by petrology and metallurgy, turns to the remaining information he can get from his colleagues in the natural sciences. These tell him the environmental conditions in which the people he is studying lived; he now sees his material remains not as isolated artifacts but in the context of their original environments. Dating
Having analyzed his discoveries according to their form, material, and biological association, the archaeologist then comes to the all-important problem of dating. Many material remains of man’s past have no dating problem: they may be, like coins, or most coins, self-dating, or they may be dated by man-made dates in written records. But the great and difficult part of the archaeologist’s work is dating material remains that are not themselves dated. This can be done in one of three ways. Sometimes an object from another culture, the date of which is known (e.g., in the case of pottery, by its style), is found at a previously undated site. Then, using the relative dating principle (see below) the archaeologist reasons that the material found with the imported object is contemporary with it. Conversely, an object from an undated culture may be found at a site whose date is known. Thus nonliterate communities can be dated by their contact with literate ones. This technique is known as cross dating; it was first developed by Sir Flinders Petrie when he dated Palestinian and early Greek (Aegean) sites by reference to Egyptian ones. Much of the prehistoric chronology of Europe in the Neolithic, Bronze, and Early Iron ages is based on cross dating with the ancient Near East.
Aside from cross dating, the archaeologist faced with material in a site having no literate chronological evidence of its own has two other ways of dating his material. The first is relative, the second absolute. Relative dating merely means the relation of the date of anything found to the date of other things found in its immediate neighbourhood. As has already been described, this method also plays a part in cross dating. Stratigraphy is the essence of relative dating. The archaeologist observes the accumulation of deposits in a gravel pit, a peat bog, in the construction of a barrow, or in accumulated settlements in a tell, and, like the geologists who introduced the principles of stratigraphy in the late 18th and early 19th centuries, he can see the succession of layers in the site and can then establish the chronology of different levels of layers relative to each other. In the excavation of a great tell like Ur or Troy the relative chronology of the various levels of occupation is the first thing to be established. Some archaeologists, even until quite recent times, have mistakenly supposed that depth below ground level is itself an indication of antiquity.