236 



MR. C. A. MATLEY ON THE 



[May 1900, 



beds resume their north-easterly dip. A sketch of the headland, taken 

 from near the Middle Mouse (Ynys Badrig), is reproduced in fig. 2. 



Fig. 2. — Llanlliana Head, sketched from near Ynys Badrig. 



[Scale : 20 inches = 1 mile.] 



The beds are cleaved obliquely to the bedding-strike, and in one 

 faulted portion of the banded beds above Porth Llanlliana I observed 

 the cleavage-strike to be at right-angles to the strike of the bedding. 



(3) West of Porth Llanlliana. — The basal conglomerates 

 and grits and the banded beds come in here between converging 

 faults. As at Llanlliana Head the general structure is a syncline 

 followed to the north by an anticline ; but the rocks are much broken 

 by faults (some of which are thrusts), and the detailed structure is 

 seen to vary considerably as we pass from west to east. All the beds 

 are cleaved at high angles. Some of the bands of conglomerate are 

 very coarse. 



On the coast the conglomerate is faulted against the quartzite, 

 inland it lies directly upon it, but the purple conglomerate which 

 was so conspicuous a feature of the basal beds to the east is here 

 represented by a pale conglomerate. A few purple bands 

 may be seen, however, on the coast (see fig. 13 of my previous 

 paper, vol. lv of this Journal, p. 673), close to which I have found an 

 assemblage of fossils similar to those recorded from Ogof Gynfor. 



(4) Ogof Gynfor. — Some account of the rocks here, with a 

 figure of the coast-section and a list of fossils, was given in 

 my previous paper {op. cit. pp. 640, 648). Its structure consists 

 of two broken synclines, between which appears a shattered anti- 

 cline of quartzite. The northern syncline is cut out to the east by 

 the overthrust of calcareous beds of the Llanbadrig Series. Faulted 

 in between the quartzite and the overthrust is the Penterfyn iron- 

 stone, the details of the section exposing the latter being as 

 follows : — 



Feet. 



{Ironstone in flaggy beds, with shaly partings which contain 1 ,- 

 Glenkiln graptolites. (Top not seen.) J 

 Black siiale 2 



Cb. Blue sandy shale 2 



(Base not seen, but soon faulted against quartzite.) 



