194 



IGNEOUS ROCKS. 



TJPPEB 



Gaxleby. 

 Wall-case 4 



Brown brecciated rock, containing large decomposing f e l_ 

 spathic fragments in a yellowish-brown felspathic base^witb 

 fragments of felspar crystals. 

 From the Llandeilo flags. 



79 



Pembroke shire . 

 •Brecciated felspathic rock, interstratified 



in 



thick beds with slates of the Llandeilo flag series. Strumble 

 Head. Goodwick. near FisWimrd. PptnKfnVooinV Q Man 40 



SO. 



-Fragment of the same, Strumble Head, Goodwick 



f-1 3 T> * 1 t « * 



near Fishguard, Pembrokeshire. 



Felspathic porphyries, &c. — Lava Streams. 



Specimens from felspathic lava beds that are asso- 

 ciated WITH AND CHIEFLY OVERLIE THE VOLCANIC ASHES OF 



Cader Idris and Aran Mowddwy, &c. ; the whole lie 

 near the base of the lowest part of the Llandeilo flags. 



91.— Calcareous amygdaloid. — Ridge of Cader Idris, 

 one mile south of Tyn-y 



Merionethshire. Map 59, 

 of kernels of calc spar. 



Nant, south-west of Dolgelly, 

 N.E. Green talcose rock, full 



This specimen has originally been part of a scoriaceous 

 vesicular mass (a cellular lava like No. 4, Case 2), the 

 vesicles of which have afterwasds been filled up by infiltra- 

 tions of carbonate of lime. On the surface the lime has 

 subsequently been dissolved out, and it has again become 

 vesicular. 



92.— Amygdaloid.— Buarth Glas, by turnpike road 2\ 

 miles north-west of Dinas Mowddwy, Merionethshire. 

 Map 60, N.W. Blackish-green felspathic rock, with ker- 

 nels of quartz interspersed. 



This specimen is from the great masses of felspathic 

 porphyries, &c, that overlie the volcanic ashes, No. 1 to 

 12, of Cader Idris. Aran Mowddwy, Moel OfFrwrn &c. 



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