KEAE NEW GALLOWAY. 



571 



The great variation in the amount of effect produced by an 

 intrusive mass at a given distance has often been noticed. It is 

 noticeable even in different bands of these shales. "Within 100 

 yards of the granite some bands show no alteration, whilst others 

 become hardened into a compact, but generally fissile, rock with a 

 good deal of muscovite in flakes so small as only to show by their 

 sparkle. For about the last three yards the rock, where the 



Fig. 1 . — Map of the Knocknairling Hill and Burn, near 

 New Galloway. 



K/^OC/fNAinLtN'G 









Scale. 2 Inches to a,' Mile. 



Shales. A. Little altered, but containing bands an inch or two broad, 

 in which much white mica and garnets have been developed. 

 JB. Little altered, except at the junction. 



C. Altered grits and flags, with narrow bands of unaltered shale and 



of chiastolite-mica-schist. 

 D, E. An alternating series of shales, flags, and grits. Those at D are 

 the same as the rocks of the series 0, exposed lowest on the hill- 

 side. 



^ 



Granite. 



Contour-lines, in feet. 



junction is exposed, rapidly lightens in colour and changes in 

 character. It finally becomes a light grey, almost white, granular 

 rock with black patches, of about the size of a sixpenny-piece. It 

 shows on a cross fracture no signs of foliation, though it has a 

 tendency to^ break along planes covered with small flakes of mus- 

 covite. This rock weathers with the granite so that it is difficult to 

 tell on a weathered surface where the margin is at the junction. 

 The microscope, however, shows that that there is no shading off, 

 and that the altered shale has a marked character of its own. 

 Q.J.G.S. No. 184. 2t 



