﻿134 • ME. E. H. EASTALL ON THE [May I9IO, 



Besides the above-described connected series a large number of 

 specimens have been collected and examined from various scattered 

 and isolated exposures within the limits of the grey-slate belt, as 

 indicated on the map (PI. XIY) ; all of these are very similar, and 

 it is unnecessary to describe them in detail. In certain bands 

 andalusite occurs in fair quantity, but is by no means universally 

 distributed. 



Prom the foregoing description of the progressive metamorphism 

 of the grey-slate series, it appears that the dominant minerals 

 produced are cordierite and mica, while andalusite is quite sub- 

 ordinate, and garnet and staurolite occur only in immediate contact 

 with the granite. 



It was hoped that in this series it would have been found 

 possible to distinguish definite zones of metamorphism and to 

 indicate them on the map ; but, owing to the very gradual transi- 

 tions and the absence of exposures over large areas, this was found 

 impracticable and the idea was abandoned. 



Type III.— The Grey Grit. 



Owing to the poorness of the exposures, it has been found very 

 difficult to map the boundary between the grey flags and slates 

 just described and the grey grits of the central portion of the 

 aureole. These two types undoubtedly pass one into the other 

 by insensible gradations, and the line traced on the map must be 

 regarded as a mere approximation over part of its length. On the 

 north-eastern side, however, on Bowscaie Pell, the distinction on 

 the ground is clear, and the boundary runs on the south-east side 

 of Bowscaie Tarn. Passing towards the south-west, another good 

 continuous section is seen in the upper part of Blackhazel Beck ; but 

 after this, exposures of rock in place are few and far between, until 

 we reach the higher slopes of Skiddaw. On the northern side 

 there are fairly good exposures in Wiley Gill and Burdell Gill, and 

 a long continuous section in the bed of the Caldew, near it& 

 junction with Grainsgill. Here the grits are seen actually in 

 contact with the granite and greisen of Grainsgill. Unfortunately, 

 in none of these cases does the section run along the strike of the 

 beds. All the tributaries of the Caldew are dip-streams, and the 

 course of this river itself near Grainsgill, where the best exposures 

 occur, is distinctly oblique to the strike. It is, therefore, impossible 

 to be certain that a series of specimens from any of these localities 

 were originally of the same lithological character. The Grainsgill 

 section affords the nearest approach to the desired arrangement, 

 and, from an examination of other parts of the grit-belt, it appears 

 that little variation may be expected; this area is therefore selected 

 for description as most typical of the metamorphism of this series. 



The ^grit-belt has a maximum width of about a mile and a half 

 in the centre, and completely encloses the largest granite mass; 

 the southern side of the Grainsgill mass also abuts against it. 



