In such cases subjective element cannot be ruled out.
But, for a single culture site the method is quite reliable.
Quite convincing dates are sometimes arrived at by importing parallels from other contemporaneous cultures.
This parallelism is formed due to trade relations, particularly wehen trade followed in both directions.
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.
Specialists in the field of astronomical research placed this solar eclipse as on 15 June 763 B. The Almanac belonging to Maya culture of Central America helped in dating several important sites accurately on the basis of astronomy.
Once a type has been classified by the aid of its context further specimen of the same type, even when found in isolation, can be assigned their place in terms of dates.