The organisms which can be used in radiocarbon dating include charcoal, wood, marine shell, human or animal bone, antler, peat; in fact, most of what contains carbon during its life cycle can be used, assuming it’s preserved in the archaeological record. The farthest back C14 can be used is about 10 half lives, or 57,000 years; the most recent, relatively reliable dates end at the Industrial Revolution, when humankind busied itself messing up the natural quantities of carbon in the atmosphere. Further limitations, such as the prevalence of modern environmental contamination, require that several dates (called a suite) be taken on different associated samples to permit a range of estimated dates.
http://archaeology.about.com/cs/datingtechniques/a/timing_3.htm
http://archaeology.about.com/cs/datingtechniques/a/timing_3.htm
That's Archaeology 101 material. Try again.