358 



PEOCEEDINGS OF THE GEOLOGICAL SOCIETY. [JuilG 19, 



XXXiy. Metamorphic shale from beds near the entrance of the 

 same quarry, a. Carbonates removed by diluted cold hydrochloric 

 acid ; 6. The undissolved residue ; (7. Composition of the residue. 



XXXV. Irregular metamorphic schistose rock from the south 

 slope of the "West Ragged Stone. 



Of these, XXYII. to XXX. have less silica and more alumina than 

 clay-slates of primary strata, and they differ more in structure than 

 in composition from the beds of volcanic ash with which they are 

 interstratified. 



The black shales, XXXI. and XXXII., have a composition nearly 

 resembling that of the thin bands of trachytic ash in the Hollybush 

 sandstone, XXIII. and XXIV., and of the lava-beds west of Castle 

 Morton Common, XXV. Their structure only is different, being 

 such as would result from the deposition of their particles in a 

 minute state of subdivision in still water containing organic matter. 

 The others, XXXIII. to XXXV., resemble the lavas erupted after the 

 deposition of the Black Shales, and were probably derived from 

 the mechanical deposition of volcanic matters ejected during the 

 eruptions. 



IV. Bedded Traps, Lavas, and Felstones of the Herefordshire Beacmi, 

 South and South-east of the British Camp. HoU, loc. cit. pp. 92, 

 93; Phillips, loc. cit. pp. 30, 3]. 



1. Trappean rocks, mechanically deposited, form the mass in which 

 the cave is excavated, and occur in various parts of the east buttress. 



2. Eocks of similar characters, but higher specific gravity, are 

 found over trap-dykes near the footpath south of the cave, and on 

 the east of the ridge on which it stands ; they contain much lime, 

 and in parts have the yellowish- green colour of massive epidote. 

 They appear to be older than those last-mentioned, some of which, 

 towards the east, contain included fragments of them. 



3. Eed rock, containing a few small quadrangular crystals of 

 felspar, occasional fragments of rock resembling altered shale, and 

 epidote, apparently formed by the mixture of volcanic ash with 

 water, and subsequently modified in structure by intrusive rocks 

 with which it is in contact. 



4. Beds of bluish trisilicated lava, containing epidote in cavities, 

 as in XXV. 





1 



i 





Oxide of 

 Copper. 



Si 



P 



So 



3^ 



s i 



XXXVI. 



XXXVII. 



XXXVIII. 



XXXIX 



48-61 

 49-37 

 50-37 

 58-61 



14-14 



15-80 

 15-83 

 17-01 



13-39 



10-82 



9-30 



13-99 



Trace. 



Trace. 



0-70 



Trace. 



0-40 

 Trace. 



7-94 

 11-00 

 14-63 



4-47 



6-16 

 6-40 

 4-02 



2-87 



3-47 



4-00 

 1-65 

 2-19 



5-89 

 2-59 

 3-50 

 0-86 











XXXVI. Bedded trappean rock, cave. G=2-826-2-852. 



