The diffusion of these farmers across Europe, from the Aegean to Britain, took about 2,500 years (6500–4000 BCE). The Baltic region was penetrated a bit later, around 3500 BCE, and there was also a delay in settling the Pannonian plain. In general, colonization shows a "saltatory" pattern, as the Neolithic advanced from one patch of fertile alluvial soil to another, bypassing mountainous areas. Analysis of radiocarbon dates show clearly that Mesolithic and Neolithic populations lived side by side for as much as a millennium in many parts of Europe, especially in the Iberian peninsula and along the Atlantic coast.