Multi-disciplinary research led by a city-based archaeologist has confirmed the presence of humans in the Ayodhya hills of Purulia district about 42,000 years ago, a finding that pushes Bengal’s archaeological calendar back by 22,000 years.
Bishnupriya Basak, who teaches archaeology at Calcutta University, sealed the findings after more than 12 years of intensive exploration and excavation of 25 Stone Age sites she had discovered between 1998 and 2000, while working with the Centre for Archaeological Studies & Training, Eastern India. The breakthrough came recently, when the researcher returned to the forests of the Ayodhya hills in 2011 to build up on her findings using a technique called optically stimulated luminescence (OSL) that establishes the antiquity of tools of a particular age.
Prior to this discovery, the earliest evidence of human presence in Bengal was at Sagardighi in Murshidabad district. The tools found there were dated to approximately 20,000 years ago.
The foothills of the Ayodhya Hills where the monolithic weapons were found (The Telegraph)
An extraordinary development and a breakthrough in the otherwise hazy chronology of eastern India, this marks a welcome trend in research. In the subcontinent, the earliest evidence of microlith-using cultures—hunter-gatherer populations that made and used the types of light stone implements found in the Ayodhya Hills—is in Metakheri, Madhya Pradesh, which dates back to 48,000 years ago. Microlithic tools found at Jwalapuram in Andhra Pradesh, are from 35,000 years back and those discovered in Sri Lanka are from 25,000 years back.
In the subcontinent, most microlithic sites are reported from alluvial context, sand dunes or rock shelters. There are very few late Pleistocene colluvial sites. Colluvium is the material that accumulates at the foot of the hill ranges — a mix of sediment, gravel and pebbles, all brought down the hill slope through natural gravitational flow. When they form a stable surface, as in the Ayodhya hills, they are a good location for prehistoric populations to settle.
According to geo-archaeologists, the Ayodhya discoveries hold the key to research in several fields, from environmental studies to paleontology.
The samples had been first sent for pre-treatment and chemical analysis to the Wadia Institute of Himalayan Geology, where senior scientist Pradeep Srivastava dated them as belonging to the Late Pleistocene period, roughly in the bracket of 42,000-25,000 years before the present. The rocks from which these tools had been made were identified by the Geological Survey of India as chert and felsic tuff.
Subrata Chakraborty, professor of prehistory at Visva-Bharati, said accurate dating had long been a problem in Bengal because of inadequate infrastructure. An intriguing facet of the discovery is that no trace of the raw material used in these tools was found in the near vicinity, suggesting that the early hunter-gatherers had travelled quite a distance to get their stones. Such instances are, of course, not uncommon even among living hunter-gatherers. Geo-archaeologist SN Rajguru, a veteran geo-archaeologist who formerly taught at Pune's Deccan College, said the Ayodhya discoveries had opened a whole new chapter in Bengal’s history.
Bengal was very much a part of the climatic changes during the last glacial period. So far it had been assumed that Bengal was always humid with plenty of rainfall. Now we have evidence that the whole of the Rahr region of the state also experienced the dry climate that was caused by the period’s peak in glaciations. The sea level must have been lower by about 100 metres.