Wolffia using a increment borer to age-date an old sierra juniper (Juniperus occidentalis var.australis) on a steep 9,000 foot ridge of Pine Mountain in the San Gabriel Range of southern California.The following animation will provide you with an example of how cross-dating is used. It is increasingly difficult for prehistorians working in the twenty-first century to conceptualise the problems experienced by their predecessors, and approaches to interpretation before the 1960s are consistently criticised.
A specialized form of cross-dating, using animal and plant fossils, is known as biostratigraphy.
Culture history and diffusionism may - with hindsight - seem excessively preoccupied with classification and social evolution, and to have applied unsophisticated historical interpretations instead of asking fundamental questions about human behaviour.
It must be made clear at the outset that typology is not, strictly speaking, a dating method, but a means of placing artefacts into some kind of order.
Close-up view of the increment borer, showing the slender wood core that is extracted from the trunk.
The core is sanded and treated with a wood oil to make the rings more distinct.