240 ME. C. A. MATLET ON TFfE [May I9OO, 



section shows the fractured condition of these rocks so well that 

 further description is unnecessary. 



Near Llanbadrig Church the shaly beds give place to similar 

 rocks, with rather thick irregular bands and lenticles of quartzite 

 and quartzose grit. As they are followed towards Ogof Gynfor 

 they are observed to include some limestone, and to pass up into 

 pebbly slates. These beds are much crushed, and are succeeded 

 by the faulted-in Llandeilo rocks of Ogof Gynfor. 



North-east of Ogof Gynfor. — The thrusting of the Llanbadrig 

 Series over the Ogof Gynfor Llandeilo strata brings up a long strip 

 of impure limestone that is traceable inland to Llanlliana iarm. 

 The lower beds of this zone are calcareous slates or shales, thinly 

 laminated, but frequently welded into a limestone, and they pass up 

 into massive limestone. The apparent dip is steeply to the north. 

 Thrusts occur in these beds, bands of grey limestone terminate in a 

 tongue-like manner, and the whole is much jointed, veined, and 

 irregular. Some of the limestone splits into large phacoids by the 

 development of curved joints. These calcareous beds are limited 

 to the north-east by a nearly vertical fault. 



Gritty slates with pebbly and conglomeratic zones succeed, which 

 are identical with the rocks between Llanbadrig Church and Ogof 

 Gynfor. Here they pass up into a quartzite which is the highest 

 recognizable zone of the Llanbadrig Series, so that they must lie above 

 the calcareous beds just described. Consequently the junction is a 

 normal fault, but it has been evidently subjected to crush, as small 

 thrusts at a low angle have driven the pebbly slates for a short distance 

 over the dark calcareous shale and limestone. The coast-exposures 

 show that this pebbly group contains two or three thin lenticular 

 zones of limestone which have been broken by gently-sloping thrust- 

 planes and the dislocated portions carried 1 to 3 feet southward. 

 A more important thrust, hading at 35° from the horizontal, may 

 be followed from the base to the summit of the cliff near by. 

 Inland, towards Llanlliana Farm, these beds are finer, with tiny 

 quartz-pebbles and flaggy bands of quartzose grit. 



A white quartzite succeeds these pebbly beds. On the coast it is 

 cut out before reaching the base of the cliff, by a fault which lets 

 down the Llandeilo rocks. Inland it is about 100 feet thick, and 

 the Llandeilo Beds rest upon it. This quartzite presents remark- 

 able stratigraphical features, and its significance will be separately 

 discussed (p. 244). 



The upper portion of the Llanbadrig Series is repeated at Porth 

 Llanlliaua. Calcareous shales, contorted and cleaved, with some 

 massive limestone, are succeeded by slaty beds, the upper part of 

 them pebbly, which pass into the quartzite-zone of Llanlliana Head. 



From the foregoing descriptions a general idea of the Llanbadri«- 

 succession may be gained ; the lowest beds are the 



Trwyn y Pare Grits and Slates, seen at Penrhyn, Try wn y Pare, 

 and Llanbadrig; they are followed at Penrhyn, Trwyn y Pare, and 

 Llanbadrig by the T r w y n y Pare Limestone. 



