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st. david's, Pembrokeshire. 



209 



Upper 

 Galiert. 



This rock is in places nearly granitic in structure, and is 



probably connected underground with the intrusive mass of 



granite which runs from Brawdy, by Hay's Castle, to the Wall - case4 « 

 neighbourhood of St. Lawrence. 



167— Syenitic rock.— East side of Forth Lisky, 2 miles 



south-west of St. David's. 



light green hornblendic mineral. 

 . From the same mass as No. 165. 



Felspar and quartz, with a 



168. 



Amygdaloidal fel spathic trap. 



Penmaen 



Melyn, opposite Ramsey Island, 2\ miles south-west of St. 

 David's. Green felspathic rock, with kernels and crystals 

 of pinkish felspar; those near the outer surface browned 

 by oxidation, or entirely removed. 



This rock belongs to a mass which, in general character, 

 belongs to the greenstone family, and, like the neighbour- 

 ing syenite of Forth Lisky, alters the Cambrian rocks so 

 much that, on the ground, it is difficult to determine where 

 the igneous rock ends and the altered rock begins. 



169. 



Darl- 



Greenstone. 



Penmaen Meleyn, St. David's, 

 blackish-green compact hornblende and felspar rock. 



170— Cambrian rock, altered by Nos. 167 and 168. 

 Porth Lisky, St. David's. 



1 70a.— Cambrian rock, as above.— Penmaen Melyn, St. 

 David's. 



In places these rocks have been so much altered that they 

 have evidently been actually fused, or nearly so. Some- 

 times they become porphyritic, and exhibit crystals of fel- 



spar. 



Case 



171.— Felspar trap.— West side of Solva Harbour, St. 

 David's. Dark bluish-grey felspathic rock, with small 

 white felspar crystals. Outer surface bleached with a 

 pumiceous look. 



172.— Felspar porphyry.— Whitchurch, near Solva, 

 St. David's. Map 40. Greenish-grey and white felspar ; 

 the latter crystallized, and a few small hornblendic crystals. 



This rock occurs in four bosses north of St. Elvis. They 



