Radiocarbon dating uses the naturally occurring isotope Carbon-14 to approximate the age of organic materials. Often, archaeologists use graves and plant remains to date sites.
The number of protons in the nucleus of an atom determines the element.
Other corrections must be made to account for the proportion of throughout the biosphere (reservoir effects).
Additional complications come from the burning of fossil fuels such as coal and oil, and from the above-ground nuclear tests done in the 1950s and 1960s.
This Radiocarbon reference must originally have been translated from Russian and it is not unreasonable to suppose that there was some loss of descriptive clarity as a result.
But it seems pretty clear that what is being described here is certainly not "Pennsylvanian coal".