OF THE MALVEEX HILLS. 



505 



which produced the schistosity of the rock. The quartz-grains, 

 which are quite irregular in form, contain fluid-lacunae, often ranged 

 in lines, and these streams of enclosures lie sometimes in the direc- 

 tion of the fine-grained quartzitic bands, at others in the direction 

 of the micaceous bands. 



The rock may not inaptly be termed a micaceous quartzite-schist. 



Part of a section of this rock is shown in PI. XXI. fig. 2, as seen 

 by ordinary transmitted light. 



No. 32. Raggedstone Hill, Eastern Sjmr, East side, North end, near 

 the middle. — A very compact, bluish-grey rock, translucent on the 

 edges, resembling quartzite, with a faint laminated structure, and 

 showing under a pocket-lens numerous minute, glistening, crystalline 

 facets or cleavages. 



Under the microscope this is seen to be a quartzite containing 

 numerous but very minute scales of mica, which, in places, show a 

 tendency to segregate in irregular lines. They are not, however, 

 sufficiently numerous in proportion to their size to impart a fissile 

 character to the rock. 



No. 33. Vein, about a foot in thicJcness, in first quarry on South 

 side of TheWych, Western side of the JIalvemRange. — A very coarsely 

 cn'stalline rock of a deep flesh-red colour, with spots of greyish or 

 bluish- white quartz. 



Under the microscope the felspar appears to be microcline, the 

 extinction-angle generally ranging from about 12° to 15°. The 

 cross-hatched twinning on the pericline and albite types, so common 

 in this mineral, is not to be detected in the section here described, the 

 crystals showing but one set of twin-lamella?, and in some cases none. 

 The crystals are sometimes cracked and faulted, as shown in PI. XXI. 

 fig. 3. Some opaque white matter, probably kaolin, is present in 

 small flecks and streaks. The quartz contains fluid-lacunae, often 

 showing a faint linear arrangement. This is a good example of the 

 pegmatite-veins so common in the Malvern Hills. Of their intru- 

 sive character there can be no doubt. An admirable example of a 

 branching vein may be seen traversing schists in an abandoned 

 quarry on the east side of the Paggedstone and towards the -southern 

 end of the hill. I am not, however, inclined to think that the 

 coarse pegmatite forming the northern part of the ridge of Swin- 

 yard's Hill is to be regarded as a vein-rock or dyke, or as a series of 

 veins ; it is more likely to be part of a deep-seated rock belonging 

 to the lower, and probably to the lowest exposed portion of the 

 ArchEean series in this district. 



In reviewing the results of the microscopic examination of the 

 Malvern rocks, we must in the first place separate those rocks which 

 exhibit foliation or lamination, or of which the origin has been 

 sedimentary, from those which show no such structure, and which 

 must, without doubt, be regarded as eruptive. This is the more 

 needful since much diversity of opinion exists concerning the inter- 

 pretation which should be put upon the phenomena of foliation. 

 We shall by this means classify the rocks of the Malvern Eange into 



