Yol. 62.] BTJTTERMERE AND ENNERDALE GRANOPHYRE. 257 



granitic in the usual sense (PI. XXVII, figs. 1 & 2). A short- 

 distance from the margin [4751] granophyric structure begins to 

 appear ; specimens taken from the middle of the laccolite, as for 

 example at the head of Near Ruddy Beck, are poorly-developed 

 granophyres [4753]. 



On the hillside a few hundred yards west of Scale Force, the 

 junction with the Skiddaw Slates is very well seen, and the 

 metamorphism can be well studied here, Close to the intrusion 

 the slate is altered to a very compact greenish hornstone, and the 

 junction is absolutely sharp. The original bedding of the slate 

 is well seen on weathered surfaces, but there is no trace of cleavage ; 

 and it is quite clear that the intrusion of the igneous rock was 

 anterior to the movements which produced the cleavage of the 

 Skiddaw rocks. 



Along the northern side of this laccolite are a number of lines 

 of disturbance, which have produced small tear-faults crossing 

 the junction at right angles ; these are made conspicuous by a 

 great development of haematite. The fine waterfall of Scale Force, 

 156 feet high, is determined by one of these ; and the stream has 

 here cut a very deep gorge along the line of weakness. 



The second mass is much larger, and the laccolitic form is not 

 here so obvious ; it is probably concealed, to a certain extent, by 

 incomplete denudation and faulting. In this case granophyric 

 structure is carried to a very high degree of perfection. The 

 margin of this intrusion is variable in character, sometimes 

 granitic, more often coarsely graphic; and in some localities 

 felsitic, as, for example, in Revlin Crag, on the south side of 

 Ennerdale Water, and at Silver Cove [4754], farther east. The 

 farther we proceed from the margin the finer in texture and more 

 complex is this micrographic or granophyric structure seen to 

 become [4755]; see PI. XXVIII, fig. 1. The best examples come 

 from near the middle of the exposure, at Mart Knott, Stair Knott, 

 and Sail Hills, south of the head of Ennerdale Water, and in the 

 bed of Woundell Beck, close to its junction with the River Liza 

 [4756-59] ; see PI. XXVIII, fig. 2. Here also the normal rock 

 is traversed by fine-textured veins of an aplitic nature, which show 

 no micrographic intergrowth at all, and are singularly poor in 

 ferromagnesian minerals [4760-61]. They are presumably of 

 later date than the rest. 



On the south-east side of this mass, on the flanks of Seatallan, is 

 seen a considerable development of a rather more basic variety, 

 characterized by the occurrence of needle-shaped crystals of ferro- 

 magnesian mineral, often an inch long. 



In the smaller laccolites, in the Wastwater district, some in- 

 teresting variations occur ; and especially in the neighbourhood of 

 Mecklin Wood, about a mile north-east of Santon Bridge, the whole 

 intrusion becomes very complex, and some peculiar rock-types are 

 found. These are the freshest rocks in the district, and their study 

 has thrown much light on the more weathered examples from the 

 northern part of the area. 



