The basic features of the British geographical position, topography and climate

The British Isles lie at the juncture of several regions with past episodes of tectonic mountain building. Theseorogenic belts form a complex geology which records a huge and varied span of earth history. Of particular note was the Caledonian Orogeny during the Ordovician Period, c. 488–444 Ma and early Silurian period, when thecraton Baltica collided with the terrane Avalonia to form the mountains and hills in northern Britain and Ireland. Baltica formed roughly the north western half of Ireland and Scotland. Further collisions caused the Vatican in the Devonian and Carboniferous periods, forming the hills of Munster, south-west England, and south Wales. Over the last 500 million years the land which forms the islands has drifted northwest from around 30°S, crossing the equator around 370 million years ago to reach its present northern latitude.