41. The former stopping service ( which called at Seaburn, East Boldon and Brockley Whins ) is now provided only by the Metro. 42. The crags are an outcropping of the Whin Sill, an igneous rock, dolerite, associated with magma flows from ancient volcanos. 43. The land on which Spennymoor now stands was once a vast expanse of moorland covered with thorn and whin bushes ( Spenny Moor ). 44. An area known to have been mined is shown as extending NNW towards Whins of Milton village and must have passed under the burn. 45. Studies of the petrology of the dolerites of the Whin Sill complex have revealed significant differences between the Little Whin and the Great Whin. 46. Studies of the petrology of the dolerites of the Whin Sill complex have revealed significant differences between the Little Whin and the Great Whin. 47. Studies of the petrology of the dolerites of the Whin Sill complex have revealed significant differences between the Little Whin and the Great Whin . 48. The original 1839 Brockley Whins station, on the Brandling Junction Railway, only had a platform on the down line ( towards Newcastle ). 49. The site is an outcropping of the Whin Sill which gives rise to a distinctive flora particular to the thing soil conditions on this bedrock. 50. Geologically, Illgill Head and Whin Rigg are part of the Borrowdale Volcanic Group, typical for the southern-western area of the Lake District.
