Accuracy of ancient dating methods
It was all clear when in 1859 Charles Darwin published his "On the Origin of Species".
The 'progress' shown by the fossils was a documentation of the grand pattern of evolution through long spans of time.
Besides the order of fossils in the rocks, another method is the use phylogenetic trees.
Phylogenetic trees are used to show how all the species of particular groups of plants or animals relate to each other.
The order of appearance in a sequence is well documented, but that is not all.The scheme worked all round the world, without fail.The next observation occurred when geologists noted how fossils became more complex through time.One records which fossil is younger and which is older.The discovery of a different means, one for which absolute dating is possible occurred in the early 20th century. Certain naturally occurring elements are radioactive, and they break down or decay at well-known predictable rates.