1869.] NICHOLSON IGNEOUS ROCKS OF THE LAKE-DISTRICT. 437 



crystals of red felspar and many crystals of quartz, most of which, 

 are doubly prismatic. The width of the dyke is about 50 or 60 feet, 

 and for three or four feet on both sides it is altered by contact with 

 the trap through which it cuts. In this altered zone it becomes a 

 compact red felstone, with a few crystals of quartz scattered through 

 it, but without any crystals of felspar. 



II. The Syenitic Porphyry between Ennerdale mid Butfermere. 



This syenitic felstone-porphyry forms an intrusive mass of very 

 considerable extent, occupying an area of about six miles from east 

 to west by about three miles from north to south, comprising the 

 mountainous district between the lakes of Buttermere and Enner- 

 dale, the lower half of the valley of the Liza and the mountains to 

 the south of Ennerdale Lake. Commencing at Bowness, a small 

 hamlet situated about midway between the extremities of Ennerdale 

 Water on its north-eastern side, the syenitic porphyry is seen to 

 form Bowness Knot, and to be immediately succeeded on the N.W. 

 by the Skiddaw Slates, Avhich are greatly metamorphosed, and are 

 converted into a hard greenish-grey rock, very compact, and exhi- 

 biting few traces of bedding. On the opposite, or south-western, 

 side of the lake the syenitic porphyry is continued nearly to the foot 

 of the lake, being probably shifted to the IST.W. by a fault. It forms 

 here the hills known as Crag Fell (or the Revelin) and Angler's 

 Crag, and it is succeeded on the N.W. by the Skiddaw Slates, which 

 form the northern flanks of Grike Eell. From their junction with 

 the syenite for a distance of nearly three-quarters of a mile the 

 Skiddaw Slates are highly metamorphosed, retaining no signs of 

 their sedimentary origin beyond the existence of lamination. They 

 are converted into an extremely hard, granular rock, much pene- 

 trated by quartz -veins, of a pink or greenish -grey colour, and 

 finely banded along the lines of lamination. As just stated, the 

 metamorphism in this locality affects a great thickness of the rocks, 

 slates of the normal character not reappearing till Fell End is nearly 

 reached. Beturning to Bowness, the boundary of the intrusive rock 

 can be traced between Ennerdale and Buttermere, pretty nearly 

 coinciding with the road between these two lakes by way of Flou- 

 tern Tarn. Between these points the syenitic porphyry is succeeded 

 to the N.W. and N. by the Skiddaw Slates, and rises on the S.E. 

 and S. into the elevations of Herdhouse, Great Borne (2019 feet), 

 and Gale Fell. 



About a mile and a half from Buttermere the cascade of Scale 

 Force is formed over a precipice of this rock. From the foot of 

 Buttermere the intrusive rock can be followed along the south-west 

 margin of the lake, nearly as far as the pass of Scarf Gap. All 

 along this hne the Skiddaw Slates are seen striking right against the 

 porphyry, and more or less metamorphosed near the line of contact. 

 The metamorphism does not appear to extend more than a few feet 

 from the porphyry; but within this zone the slates are converted 

 into a hard, laminated, greenish-grey rock. To the S.W. of this 



