Gneiss, schist and granite form the bedrock of the Ox Mountains. This wild area of uplands is covered largely with blanket bog. Some parts are extensively forested, whilst others have numerous outcroppings of rock. To the north and south the land is underlain by limestones and sandstones of Carboniferous age, and is generally farmland. Lead and copper mines were formerly worked in the Ox Mountains, but by 1900, the works had been long since discontinued.