THE SHAP GRANITE AND ASSOCIATED KOCKS. 309 



[11081. In one of the lowest rocks exposed the mica is clustered in 

 little ovoid patches about j^^ inch in diameter [1132]. This is close 

 to the granite. 



These rocks differ from the other metamorphosed ashes, which we 

 have classed as andesitic, not only in the presence of certain alu- 

 minous and other minerals, but in the smaller proportion of brown 

 mica and the absence of the lime-bearing silicates, augite and horn- 

 blende. Only one of our specimens, from the uppermost bed 

 exposed, shows green hornblende as well as brown mica. The two 

 minerals are not miugled, but occur in alternate narrow bands, 

 about twenty in an inch [763]. Possibly this rock originally con- 

 tained some calcareous matter, as well as clastic grains. 



The thin ash-beds associated with the rhyolite in the Coniston 

 Limestone group have not been minutely examined, and it would 

 probably be difficult to separate them, within the zone of greatest 

 metamorphism, from the impure limestones. Near Wasdale Head 

 Parm, however, a laminated white rock occurs between the Upper 

 Limestone and the underlying rhyolite, which perhaps represents 

 the flaky ash seen in a similar position in Elea Beck. In a section 

 [1044] it is seen to be composed in great part of minute scales of 

 colourless mica. These are collected in densely matted masses with 

 a rough parallel orientation, and also occur in rather larger flakes 

 associated with the usual brown pleochroic mica. In the same 

 slide are seen very imperfectly separated crystals giving brilliant 

 interference-tints and possibly referable to pyroxene (?). 



Finally, it should be noticed that in ashes which had already 

 suffered silicification the metamorphism seems to have been limited 

 to the production of brown mica, which forms streaks and clusters of 

 small flakes mostly surrounding grains of magnetite. Eocks of this 

 type show no difi'erence between specimens taken close to Wasdale 

 Head Farm, among intensely metamorphosed beds [879], and others 

 from a quarry on the high road nearly 800 yards from the granite- 

 margin. 



C. The Coniston Limestones. 



As exposed in Elea Beck plantation, in the grounds of the Hotel, 

 the calcareous rocks show few signs of metamorphism. The purest 

 beds, such as the highest seen at this locality, have a finely crystal- 

 line texture, and consist simply of a fine mosaic of calcite grains, 

 with little or no foreign matter [871]. With other beds the case 

 is different, and some are rather of the nature of calcareous shales 

 with nodular bands of less impure rock. The matrix of the Calca- 

 reous Breccia is sometimes a tolerably pure limestone, which, like 

 the preceding, has re crystallized to a calcite-mosaic, crowding the 

 dusty impurities into particular patches [862] ; but at other times 

 there is much more non-calcareous material, which seems to be 

 mostly of volcanic origin. The base of the breccia, indeed, may be 

 described rather as a calcareous ash [870]. The fragments in the 

 breccia are for the most part angular pieces of pink rhyolite, similar 



