Basing on this principle, the cultural assemblages found in different layers can be assigned a chronological personality. In practice it is found that the mounds are disturbed9 by all sorts of pits and dumps.
Charred bones are better preserved and are therefore relatively more reliable.
Charcoal is best material specially if derived from short live plants.
This dating method is also known as Archaeological Dating or Historical Chronology. These methods were relied on especially prior to the introduction of scientific methods of dating.
But, even when the scientific methods of absolute dating are available, this method of dating has not lost its importance, as many a time we have to depend solely on relative dating.
The deposit thus occurring forms layers depending on the nature of the material brought in by the people inhabiting the area.
According to this method, the upper deposits are younger and the lower deposits are older.
Astronomical data have been applied in the study of geological ice ages by calculating the curves for major fluctuation of solar radiation.
Consequently, the chronology worked out for the geological deposits helped in dating the prehistoric tools found in these deposits. There are certain antiquities and potteries which by themselves have acquired a dating value.
Antiquities and potteries of Roman origin were found in association with the finds of Indian origin.
With the aid of these dated imports it was possible to date the associated Indian objects to the first two centuries A. Similarly NBP and PGW has helped in fixing the chronology of numerous sites. Sometimes dates are also obtained with the assistance of astronomy.
Clay tablets found in West Asia contain inscriptional evidence with regard to the occurrence of a solar eclipse.