In the Winter 2007 issue of Planet Earth, Glynis Jones, Caitlin Buck,Mike Charles, Tom Higham and Sue Colledge talk about their project to date the spread of agriculture into and across Europe using the appearance of cereal grains. They found that agriculture spread rapidly from Greece (where it first entered Europe from the Middle East) along the Mediterranean coast to Iberia, but the spread inland came more slowly, in a “stop and go” fashion.
Previous studies of the spread of agriculture were based on proxies – wood charcoal and pottery – that were easier to date. Improved technology allows the authors to date much smaller samples, opening up the possibility of actually dating the products of agriculture – charred grains. While this can create false positives (after all, you can acquire grain through trade even if you aren’t growing it), it seems like a very powerful approach.