132 CRATERS IN ANCIENT TRAP ROCK. 



fire in its formation. I saw this eminent geologist soon after his re- 

 turn from Cumberland and Westmoreland ; and if I recollect dis- 

 tinctly his opinion respecting the mountains of porphyritic trap and 

 clinkstone intermixed with slate in these counties, it was, that they 

 bore a striking resemblance to some of the most ancient volcanic 

 mountains in Auvergne, and that, like them, they had been softened 

 in situ, and elevated by subterranean heat. The operation of igneous 

 agency in these mountains is much less evident than in the porphyry 

 of Norway, if the description given of it be correct. The only por- 

 phyry occurring in unconformable beds that I have seen in Cumber- 

 land or Westmoreland, covers part of a mountain of coarse slate, on 

 the right-hand side of the road going from Kendal to the granite 

 mountain of Shap. It forms a nearly horizontal bed composed of 

 red felspar, which has an earthy texture, and contains crystals or 

 grains of quartz ; it is what the French would denominate a red 

 trachyte. Considerable fragments of the same rock are scattered 

 in the adjacent valleys, proving that at a former period, this porphyry 

 was more extensively spread over that district. A red porphyritic 

 felspar, nearly similar in composition and appearance, forms the top 

 of the mountain called Red Pike above the lake Butlermere in Cum- 

 berland. Closely adjacent to Red Pike, and forming part of the 

 same ridge, is the mountain called High Stile. Between the sum- 

 mits of these mountains is a deep crater with a small lake or tarn at 

 the bottom of it ; the sides of this crater are very steep; it is partly 

 surrounded by rude columns of clinkstone on one side ; the porphy- 

 ritic felspar of Red Pike forms the other side. The clinkstone has 

 a smooth conchoidal fracture and a greenish grey colour; it contains 

 small crystals of felspar, and is slightly translucent on the edges and 

 very fusible ; it is highly sonorous when struck with a hammer. The 

 height of High Stile is 2100 feet above the level of the sea; the 

 depth of the crater is about 500 feet ; the side nearest the lake of 

 Buttermere, by which alone it can be entered, is partly open. Situ- 

 ated as it is on the summit of a very narrow steep mountain range, 

 that divides the valley of Buttermere from Ennerdale, no conceiva- 

 ble operation of water could have scooped out the crater, and the 

 bed of the lake within it. 



Though the rocks which surround this crater are closely allied to 

 volcanic rocks, and have probably been subjected to the agency of 

 subterranean fire, yet the crater is not composed of lava and scoriae, 

 like that of modern volcanoes. Cader Idris, in Merionethshire, is 

 similar in composition and structure to High Stile ; it has also a deep 

 crater, with a small lake at the bottom. The opinion of Von Buch, 

 that some volcanic mountains have been upheaved bodily in a solid 

 mass, would, if admitted, elucidate the formation of these mountains: 

 the craters may not have ejected lava, but may have served for vents 

 to the elastic fluids or steam that, combined with heat, were the agents 

 by which the mountains were upheaved ; or we may suppose the 



