Geological cross-section: Southern uplands

Schematic cross-section through the Isle of Man from Langness on the east coast to Niarbyl on the west coast. The colours are the same as those used on the map, a key to which can be found there. Note that most of the rocks are dipping to the west. Generally younger rocks lie on top of older rocks so that some of the oldest rocks occur along the east coast of the Island. However, the picture is complicated by the presence of numerous faults which cause rocks of different ages to come into contact with one another, for example the Castletown Limestone (330 million years old) is much younger than the surrounding Manx Group rocks (480 million years old). An extension of the Foxdale granite (in red) can be seen below the surface in the centre of the Island.