﻿.s 2 



fc 



ffl 



COi 



& 



pq 



abruptly against the Shon Nicholas 

 Fault, ranging north-east and south- 

 west, and throwing down higher beds 

 against the conglomerate on the. 

 norch-west. 



South of the main outcrop the 

 Llathige Shales of L. 1 appear to 

 dip directly under the conglomerate. 

 These shales owe their position to 

 the Cae-gwyn Fault, which runs 

 parallel to the Shon Nicholas Fault, 

 but throws in the opposite direction T 

 and cuts out the base of the conglo- 

 merate for part of its course. 



Eeturning to the mountain-road 

 mentioned on p. 413, the Llathige 

 Shales are seen to follow the con- 

 glomerate in a natural sequence for 

 a distance of 360 yards, at which 

 point the tough concretionary Beili 

 Tew Shales are brought on by the 

 Shon Nicholas Fault, which is now 

 throwing to the south. After 400 

 yards these apparently pass conform- 

 ably under another small outcrop 

 of the conglomerate : this forms a 

 shallow syncline capping the southern 

 crest of Banc Bwk-h Cefn Sarth, and 

 is cut off on the north by the Llathige 

 Fault, introducing shales followed by 

 the Llathige Mudstones exposed at 

 L. 6. 



Some 300 yards north of this point,, 

 the Bwlch Cefn Sarth Fault, with a 

 downthrow to the south-east, repeats 

 another small area of the Beili Tew 

 Beds, capped by a small outcrop of 

 conglomerate, on the crest of Banc 

 Goleugoed ; and a small patch of 

 conglomerate crowns the little hill of 

 Allt-y-Pigyn. Both the above are 

 cut off on the north by the Goleugoed 

 Fault, which throws them into con- 

 tact with higher beds. 



VI. Detailed Structure of 

 Pen-y-ddinas and Banc Beili Tew. 



CO 



m 



In general, the structure here is 

 that of two elongated domes, which 

 have been dislocated by a number of 

 faults. The dome is most complete 

 in Pen-y-ddinas, where the rock is 



