



■Ml. 





I 



A.;.. 



:. 



c 







VOLCANIC ASHES, ETC., MEPaONETnSIIIRE. 



181 



12. Sandy felspathic and talcose layers alternating 



with purer felspathic bands. Fresh fracture grey, but 

 weathers white and pale yellow. — Moel Offrwm, near Dol- 

 gelli, Merionethshire. 



From the same beds as Nos. 10 and 11. 



13. — Felspathic and roitriiYRiTic ashes. — Y Wen alt, 



Upper 

 Gallery. 



Wall-case 4 



6 miles south-west of Bala, M 

 S.W. Grey felspathic base, inclu 



felspathic f 



Map 74, 



From a bed of ashes overlying the felspathic porphyry of 



This porphyry is the same bed as 



Y Graig and Arenig* 



that of Aran Mowddwy, but separated from it by the great 

 Bala fault. These ashes do not occur above the felspathic 

 porphyry on the Aran Mowddwy range. They extend from 

 Y Graig, 8 miles south-west of Bala to the river Maclmo, 

 near Llyn Conwy, a distance of 13 miles. 



14. — Brecciated 



/< 



stone. — Arenig, Merionethshire. Map 74, S.W. 



c sand" 

 Light 



brown rock, consisting of alternations of sandy and lino 

 brecciated felspathic fragments. The upper and lower parts 

 are finely laminated, and include a thin band of fine breccia. 



This specimen shows 



different conditions of 



chanical deposition, and is less purely ashy than the imme- 

 diately preceding specimens. 



15. — Decomposing felspathic ash. — East side of Y 



Graig, Merionethshire, 8 miles south-west of Bala. Map 

 74. Light yellowish -grey, with cavities resulting from 



/< 



filled with ochreous matter. 



18.— Felspathic and talcose ashes. — Moel-y-Menyn, 



Light 

 Weathers to a light 



argillaceous 



2 miles south-south-east of Arenig, Merionethshire, 

 grey rock, with imperfect cleavage, 

 brown colour on the joints. Emits 

 odour. 



17. — Decomposing felspathic ashes. — Top of Arenig, 



Merionethshire. Yellowish felspathic rocks, with cavities 

 produced by the removal of decomposed crystals of felspar, 



1 



