VOLCANIC SERIES OF ST. BAVTDS, 



245 



Nod's Arch we may call it), figured by both Dr. Hicks and Dr. Geikie. 

 To the left, where four birds are placed, we have Pebidian por- 

 cellanites and breccias nearly vertical. To the right, where there 

 are two birds, we have Cambrian greenish flaggy beds, also nearlv 



Pig. 2,—ShetcIi from Cliff, St. Kon's Bay, lool 



ing east. 



Caerfai beds of Cambrian 

 with seaward dip. 



Ditto, nearly vertical. 



Cambrian conglomerate. 

 Pebidian. 



vertical, but disturbed by faulting. Still further seawards purple 

 Cambrian strata of Dr. Hicks's Caerfai group dip at an angle of 

 about 45°. The strike of the Pebidian porcellanites and that of the 

 green Cambrian sandstones both agree with that of the conglo- 

 merate. 



Reference to fig. 1 will show that there are several little faults in 

 this bay. To the east over St. Non's arch there are two faults. 

 Both are omitted in Dr. Geikie's figure (I. c. p. 287), the more in- 

 land of the two by Dr. Hicks (Z. c. p. 525). These omissions make 

 the figures in each case incorrect. I have therefore redrawn the 

 arch (fig. 3). The two faults are indicated by the single line a on 

 the plan, fig. 1. Another fault, h, has slightly dislocated the strata 

 in the middle of the bay. Further westward a fault, c, running 

 S. 30° E., has shifted the line of the conglomerate about 70 feet 

 inland and to the north ; while in the next creek, the most westerly 

 of the series which form St. Non's Bay, another fault, d, running 

 inland S. 70° E., has again shifted the conglomerate inland and 

 northwards about 90 feet. An east and west fault, c, has bevelled 

 off the edges of the vertical conglomerate and caused red felspathic 

 Pebidian to lie upon it ; while in the western creek a similar fault. 



