258 Remarks on the Succession of Rocks 



of Skiddaw ; and in a branch of the river Greta between Skiddaw 

 and Saddleback, about 400 yards above the level of the sea. This 

 appears to be the highest elevation to which the primary gra- 

 nite, or foundation rock, has attained in this district; whence its 

 surface may be presumed to have an inclination or di[) each way; 

 but probably more rapid on the north than on the south side. 

 It is intersected by veins of (juartz, in which, among other mi- 

 nerals, molybdena, tungsten and wolfram have been found. 



The rocks which succeed, and have been confounded together 

 under the general name of slaty rocks, may be classed in three 

 principal divisions. The first of which, or lowest in the series, 

 forms the mountains Skiddaw, Saddleback. Grisdale Pike, and 

 Grasmoor, with most of the Newland's mountains ; extending 

 across Cromack lake, and by the foot of Ennerdale, as far as Dent 

 hill. That which reposes immediately upon the granite is a slaty 

 rock, containing a considerable portion of mica, but perhaps 

 scarcely sufficient to entitle it to the character of mica-slate ; as 

 it recedes from the granite the quantity of mica decreases, and it 

 appears marked with dark spots ; this is quarried for flooring 

 flags. Encircling the granite, this rock occupies a limited space 

 upon the surface ; it may be imagined to pass under the more 

 simple clay slate which forms the bulk of the before-named 

 mountains. 



All the rocks of this division are of a dark colour, inclining to 

 black, and generally of a slaty structure ; some of them admit 

 of being manufactured into roofing slate, which being most easily 

 procured, has formerly been the general covering of houses in 

 Keswick and its vicinity; but being subject to be shivered by 

 the weather in thin flakes, it has been superseded by the pale 

 blue slate of the next division. These rocks do not effervesce 

 with acids, they contain little or no calcareous spar: imbedded 

 crystals of a mineral called chyastolite are found in some parts 

 of Skiddaw and Saddleback ; veins of quartz and lead ore occur 

 in Thornthwaite, Newlands, Loweswater, and other places ; a 

 copper mine in Newlands, called Gold-scalp, has formerly been 

 worked to a considerable extent, and is said to have been very 

 rich ; the salt springs of Borrowdale (deserving the attention of 

 naturalists) issue from veins in this rock ; and in some places its 

 resemblance to the shale accompanying coal has induced trial 

 to be made for that mineral as in Mungrisdale, &c. with scarcely 

 the most remote probability of success, its geological position 

 being considered. 



The second division consists of rocks more varied in their 

 composition; they have been included under the genera! name 

 of slate rocks : but as those rocks which exhibit the slaty cleav- 

 age form but a small portion of this division, it does not ac- 

 cord 



