Sites, mounds, layers Archaeological sites are formed through the production, use and discarding of materials and structures. When people continue to live in the same place, their constant use and reuse of the landscape results in the build up of occupational debris, called a mound . Brief or permanent abandonment results in alteration of the landscape by wind or water activity and erosion. Occupations are detected by traces of ancient materials found in layers , which differ from one another in colour, texture and the artefacts that are found in them.
Abandonment or desertions, what are called “sterile layers”, can be identified by the absence of such traces. Generally, the lowest layers are the oldest and the highest are the most recent. The study of these layers is called stratigraphy. Artefacts found in layers can be assigned to specific cultural periods and can thus provide the cultural sequence for a site.
. A new old civilisation Subsequently, seals were discovered at Harappa by archaeologists such as Daya Ram Sahni in the early decades of the twentieth century, in layers that were definitely much older than Early Historic levels. It was then that their significance began to be realised. Another archaeologist, Rakhal Das Banerji found similar seals at Mohenjodaro, leading to the conjecture that these sites were part of a single archaeological culture.
Based on these finds, in , John Marshall, Director-General of the ASI, announced the discovery of a new civilisation in the Indus valley to the world. As S.N. Roy noted in The Story of Indian Archaeology, “Marshall left India three thousand years older than he had found her.” This was because similar, till-then-unidentified seals were found at excavations at Mesopotamian sites. It was then that the world knew not only of a new civilisation, but also of one contemporaneous with Mesopotamia.
In fact, John Marshall’s stint as Director-General of the ASI marked a major change in Indian archaeology. He was the first professional archaeologist to work in India, and brought his experience of working in Greece and Crete to the field. More importantly, though like Cunningham he too was interested in spectacular finds, he was equally keen to look for patterns of everyday life. Marshall tended to excavate along regular horizontal units, measured uniformly throughout the mound, ignoring the stratigraphy of the site.
This meant that all the artefacts recovered from the same unit were grouped together, even if they were found at different stratigraphic layers. As a result, valuable Fig. . The stratigraphy of a small mound Notice that the layers are not exactly horizontal.