sentences:  The hill is formed from a succession of Carboniferous age sandstones and mudstones, notably the Pennant Sandstone, outcrops of which occur in places around the margins of its plateau-like top.The stone has been worked in places for building stone and a number of abandoned small quarries may be seen.The lower slopes of the hill are in the Coal Measures and have been intensively worked for coal with considerable areas of landscaped opencast workings evident along its northeastern side.