Geological time is divided into periods spanning 4,650 million years. Each period is given a name. The names are usually associated either with an area where the rocks are well exposed, e.g. Devonian - Devon, or with the type of rocks that are found, e.g. Carboniferous means coal-bearing.
Our tour of Northern England geology will commence with the oldest rocks in the region and end with the youngest. The evolution of the rocks within each geological period, and localities where they can be examined will be described.