Common Pennsylvania tempers include chert, quartz, limestone, shell and more.
The same process of collecting data from various sites over many years has also provided archaeologists with a projectile point typology.
In the case of a dating typology archaeologists use the physical characteristics to identify the artifact within a specific type that correlates to a specific date or range of dates.
One example of this analysis method is historic ceramics which have been in production for hundreds of years, but not every type of ceramic has been in production for that entire period.
The clay pipe industry expanded rapidly as tobacco smoking gained popularity in both England and America. Harrington studied the thousands of pipe stems excavated at Jamestown and other colonial Virginia sites, noticing a definite relationship between the diameter of the pipe stem bore—or hole—and the age of the pipe of which it had been part.
Historical archeologists excavating English colonial sites often find pieces of white clay smoking pipes on their sites. The earliest pipes, dating to about 1600, had stems with 9/64-inch diameter bores.
Over the years archaeologists have identified different methods on how to date different types of artifacts.
They also consider historical documents and other material culture recovered from the site—such as ceramics, glass, metal artifacts, faunal and botanical samples, and features—to determine its occupation and use.Louis Binford later devised a mathematical formula to refine Harrington's method (Deetz 19).This dating technique only applies to pipe stems manufactured in England between approximately 15.Archaeologists must use the temper type to determine where the pottery originated or if it could help identify what group occupied a site when combined with other evidence.Temper is a material foreign to the clay which is added to help prevent the vessel from cracking or breaking during the drying and firing processes.Pipe stem dating You have recovered sixty-three pipe stem fragments from Verysignificantsite. Harrington's initial studies, the time periods and average bore diameters are as follows (Deetz 19): Look at the number of stems you recovered and determine which bore diameter is represented by the most pipe stems.You wish to analyze these pipe stems to determine when your site was most heavily occupied. Match the most frequently occurring diameter with Harrington's bore diameter chart above.Due to technological advances especially during the mid-16 centuries, pottery craftsmen were able to create more refined pastes (less porous), glazes more purified in color and new methods of decorating the pottery (from hand painted to transfer printed) as time went on.It is these changes in how the ceramics were produced that created subtle clues to help the discerning eye determine the specific type of ceramic.Both of these characteristics are also used to narrow down a date range.So not only do we have a typology based on the type of ceramic, but we also have typologies with determined dates of manufacture for each of the different shapes and forms of decoration.