722 



MISS C. A. EAISIN OS THE 



in the mica-chlorite layers, rare elsewhere. The signs of a crushing 

 of the rock are very evident ; the grains are of varying sizes, their 

 boundaries shade off in polarizedlightwith an appearance of secondary 

 deposition, and many are dirty and less clear than usual ; the 

 micaceo-chloritic layers also are crumpled as in the true mica- 

 schists. Like this last specimen, a mass of rock from the north of 

 " Snapes" Point might be described as a kind of chlorite-schist ; but 

 it exhibits, even in the hand-specimen, a large amount of mica. It is 

 dark-greenish in colour, tough, and weathers to a very rough surface, 

 partly ridged from plates and fibres of mica, partly pitted with 

 roundish hollows irregularly weathered out. A slide cut from this 

 rock shows chlorite largely present in aggregated folia, but, inter- 

 crystallized with it, flakes of white mica in much abundance. This 

 mica seems to agree with that in the true mica-schist, and shows 

 the zigzag crumpling of the folia which is so marked in that series. 

 As in chlorite-schists, granular epidote is abundant, and large grains 

 occur with an indication of cleavage-planes and showing a tendency 

 to break into smaller fragments. Within the ground-mass are 

 fairly large isolated grains of other minerals. Some of these seemed 

 at first not easy to distinguish from quartz ; but, unless we may 

 infer its secondary deposition, several characteristics of the grains 

 make this identification difficult, as was pointed out by Professor 

 Bonney, who kindly looked at this and other slides for me. Other 

 grains present show twinning or cleavage, and very many of them 

 exhibit characters which seem to me most like those of kyanite, in 

 some cases the mineral appearing in longish forms with lines of 

 pinakoidal cleavage (a P d and a P d) crossed by some of the nearly 

 " perpendicular breaks " of the basal cleavage (0 P) described by 

 Fouque and Levy * and by Posenbusch f. In the hand-specimen, I 

 could recognize grains having pearly cleavage-faces and of pinkish 

 or pale brown colour. In the slide all the grains are fairly uniform 

 in size and similar in shape, having a somewhat elongated, elliptical 

 outline (only one showing good suggestion of crystalline form) and 

 the margin at places being fairly even. They contain various 

 enclosures, some of which seem to be epidote, sometimes in rather 

 stumpy crystalline forms ; others are clear colourless belonites ; and 

 very minute enclosures, such as are common in the quartz of the 

 chlorite-schist, are very abundant. The inclusions, especially the clear 

 belonites, extend, in many cases, in lines parallel to the long axis of 

 the enclosing grain, and often these lines are curved. In some grains, 

 cleavage runs undisturbed obliquely across the lines of enclosures, 

 so that we might perhaps infer the subsequent crystallization of 

 the enclosing mineral around the epidote and belonites. These 

 must in that case have existed previously, and the kyanite, in its 

 present condition, may be posterior to the crumpling and contortion 

 of the rock. It is interesting to note that the longitudinal extension 

 of the kyanite in some examples is roughly in the direction of the 



* Mineralogie Micrographique, p. 461. 



t Mikroskopiscke Physiographie der petrographisch wichtigen Mineralien, 

 p. o45. 



