14 



These traps have on the whole the same rock-constituents as 

 the Hornblendic Granite or Syenite of the Malveni Hills ; the 

 difference being one of arrangement or atomic constitution ; for 

 the crystalline quartz of the Syenite is here only'amorphous or 

 else in the form of cherty veins, traversing the rock in various 

 directions ; whilst only a little distance off, at Charfield Green, 

 we meet with a modification of the same rock, where, ovdng to the 

 presence of the Carboniferous Limestone of the Bristol coal-field 

 (here reaching its northern apex) the Trappean Eock presents 

 itself in form of an ''amygdaloid," containing kernels of calc-spar 

 in a Greenstone base ; the symmetrical cavities as they existed 

 when the mass was in a fused state, having originally become 

 elongated, an effect due to lateral pressure which has more- 

 over produced cleavage-planes throughout the mass. The 

 Charfield Green trap I take to be nearly the normal form of the 

 Igneous rock of this neighbourhood, unchanged by forces that 

 subsequently so altered and metamorphosed the Damory Bridge 

 mass. In this latter rock we observe here and there streaks and 

 patches of Epidote, a silicate of Alumina. This mineral which is 

 characterized at Malvern by its bright yellow colour, is here of 

 a dark or tawny olive yellow, in consequence of its association 

 with Hornblende. In a hand-specimen of the Charfield Green 

 rock, which I brought away on a former visit, I find that some 

 of the Calcite Kernels are coated with a vivid green substance. 

 This M. Delesse considers may be the result of the greenness 

 of some of the Felspar composing the rock ; but it is no doubt 

 owing to the Hornblende which combines with the Felspar to 

 produce such a bright green tint. 



At Damory Bridge the rock is quarried for road material, and 

 weathers in the quarry to a dull dark brown colour. 



Wednesday IGth August. — The fourth Field Meeting was held at 



TETBUEY. 



The object of the day's excursion being a visit to Calcot Barn, 

 Beverstone Castle, and the quarries near Chavenage. The 



