494 



HE. E. EUTLEY OX THE BOCKS 



it results from the decomposition of the felspar, and is probably 

 kaolin. 



The rock is a diorite (PI. XIX. fig. 5). 



No. 8. Quarry just above West Malvern Church. — A greenish- 

 grey gneissic-looking rock, with very minnte micaceous scales. The 

 rock varies in texture, pinkish felspar occurring in some of the 

 bands in rather coarse crystals. 



Under the microscope the chief constituents are seen to be tri- 

 clinic felspars, biotite, epidote, apatite, a little quartz, and several 

 decomposition-products. The biotite appears, by transmitted light, 

 to be mostly of a sea-green colour. The felspars often contain great 

 numbers of crystals, frequently mere microliths, which undergo 

 parallel extinction and are probably mesotype. The rock is a mica- 

 ceous gneiss. 



No. 9. Quarry just above West Malvern Church. — A foliated rock, 

 consisting of flesh-coloured and narrow dark-greenish bands. The 

 former appear to be chiefly felspar, sometimes showing crystals a 

 quarter of an inch in length. 



Under the microscope the rock is seen to be composed of micro - 

 cline in large crystals without any regular boundaries, and showing 

 the characteristic crossed twin-lamellation very distinctly, with the 

 usual extinction- angles ; quartz, biotite forming thin irregular bands 

 which mark the foliation of the rock, a little epidote and irregularly 

 shaped and sparsely distributed grains of magnetite or titaniferous 

 iron, probably the latter, as the grains are sometimes surrounded 

 by an opaque, yellowish- white substance, which may be leucoxene. 

 In general terms the rock may be designated biotite-gneiss. The 

 foliation is shown in PL XIX. tig. 6. 



No. 10. Large quarry (Leigliiori 's) at the mouth of the Dingle, 

 between the Worcestershire Beacon and North Hill. — A fine-grained, 

 bluish-grey, crystalline rock, resembling whin, and showing a few 

 minute specks of pyrites. The specimen selected is an average 

 sample of the stone now being quarried for road-metal. The rock 

 strongly attracts the magnetic needle. 



Under the microscope it appears to consist of pale-green horn- 

 blende considerably altered (but crystals occasionally give an 

 extinction- angle of 19° from the vertical axis), biotite, lath-shaped 

 crystals of felspar much decomposed, but some tolerably fresh, 

 showing micro-pegmatitic structure, and others twin-lamellae in 

 which the extinctions indicate labradorite. Magnetite is plentiful, 

 and there is a little pyrites. The biotite is of a green colour ; and 

 it is a matter of some difficulty to distinguish between it and the 

 hornblende, as they are often intimately associated. The rock is 

 apparently an altered mica-diorite (PI. XIX. fig. 7). 



No. 11. Worcestershire Beacon. North side near the summit. — A very 

 fine-grained pale pinkish-grey crystalline rock resembling elvan or 

 granulite. Seen under a pocket-lens it appears to consist of pinkish 

 felspar, quartz, and minute deep-red grains which are seemingly 

 garnets. Under the microscope the constituents are seen to be those 

 already enumerated. The grains composing the rock are all of them 



