Laurentia and Baltica collided in the Silurian and Devonian, producing a Himalayas-sized mountain range named the Caledonian Mountains roughly over the same area as the present-day Scandinavian Mountains. During the Caledonian orogeny, Finland was likely a sunken foreland basin covered by sediments; subsequent uplift and erosion would have eroded all of these sediments. While Finland has remained buried or very close to sea-level since the formation of the Sub-Cambrian peneplain, some further relief was formed by a slight uplift, resulting in the carving of valleys by rivers. The slight uplift also means that in places the uplifted peneplain can be traced as summit accordances.