362 



PKOCEEDINGS OF THE GEOLOGICAL SOCIETY. [JunO 19, 



LII. Light-reddish-white rock, becoming grey when the oxide of 

 iron was reduced in the furnace, bedded with cryptocrystalline 

 trappean rock and metamorphic diorite, west of the "Wych Hill. 



LIII. Dark-green trappean rock, with no distinct crystallization, 

 bedded with the rock last described. 



YI. Quartzo-Felspathic Veins. 



These have been described by Professor Phillips under the desig- 

 nation of " crystallized felsparite " {op. cit. pp. 42, 43). 



These rocks are of two distinct types, characterized by the atomic 

 amount of the silica. In some the ratio of the oxygen of the silica 

 to that of the bases is 5 : 1, their constitution thus resembling that of 

 the series of felstones aboye described. In others this ratio is 4 : 1. 



In the large quarry west of the "Wych Hill, a loose mass, re- 

 sembling decomposed granite, was extensively penetrated by veins, 

 some of which crossed each other like veins in mud-cracks. In the 

 plane to which they were perpendicular was a thin layer, which, on 

 being removed, separated into small fragments, of which the sides 

 closely fitted each other. Their upper surfaces were smooth, and 

 coated with peroxide of iron ; underneath they were rough and 

 irregular. In one of these (LIY.), analyzed entire, the ratio of the 

 silica to the bases was 5:1. In the veins of this type, the quartz 

 is often segregated in rather large masses. In those in which the 

 ratio is 4 : 1 the quartz is more commonly found as in granite (LY.), 

 or in a fine granular mixture of quartz and felspar (LYI.). 





1 



w. 



'a 



o 



6& 



II 



&6 





H^ 



.i 





S 1 



LIV. 



LV. 



LYI. 



76-71 

 71-23 



71-22 



13-74 

 17-10 



14-82 



0-92 

 1-52 

 1-02 



Trace. 





203 

 1-85 

 1-51 



0-27 

 0-30 



0-96 

 1-07 

 1-67 



5-37 

 6-76 



8-78 



017 

 0-40 



0-58 





LIY. Quartzo-felspathic rock west of Wych HiU. 



LY. Pine-grained vein in granite, west of St. Anne's Well, chiefly 

 quartz and orthoclase (HoU, loc.cit. p. 81). 



LYI. Yein composed of grains of orthoclase and quartz, with a 

 few plates of potash-mica, in a fine-grained mixture of quartz, mica, 

 and felspar on the south side of the large quarry at North Malvern. 

 G=2-602. 



In LY. and LYI. the atomic proportion of the silica to the bases 

 is as 4: 1. 



YII. Trisilicated Felspathic Veins. 



These were well exposed in the excavation of the railway -tunnel. 

 Many of the rocks there met with were altered sedimentary deposits. 

 These were penetrated, for a distance of 160 yards, by a hard green- 

 stone rock, similar to the trap -dykes found in the South Hill and 

 elsewhere ; and at no great distance from it were masses of felspar, 

 in parts highly crystallized. The composition of the mass of this 



