1. Stratigraphy: The basic idea of stratigraphy is that the oldest layers and finds are at the bottom, and the youngest/latest are at the top.
2. Tree-ring dating or dendrochronology: Each year trees grow a ring of new wood. It is possible to work out when a tree was growing and when it was cut down by studying the rings.
3. Radiocarbon dating: plants and animals take in carbon-14 when they are alive.When they die carbon-14 begins to decay sample such as charcoal, wood, seeds and human and animal bone can be investigated when they are found. The age of plant person or animal can be worked out by measuring the amount of radiocarbon left in the sample or piece.
4. Coins: coins have a date or head of a ruler stamped on them. Objects found with them will be from the same time.
5. Post holes: darkened soil patches where posts have rotted away, this shows the shape and size of buildings.
6. Pollen: pollen grains tell archaeologists what plants were growing, when forests were cleared and when farming was spread.