Vol. 51.] THE COUNTRY AROUND FISHGUARD. 153 



guard, flows along a deep valley excavated in the strike of the slaty 

 beds for the greater part of its course ; but west of Llanychaer it 

 cuts across the strike, and has sawn its way through the diabase- 

 sheets before it reaches the sea in Fishguard Harbour. 



The wide silted-up estuary of Goodwick Bay is now a swamp 

 traversed by a few sluggish, unimportant streams. It is not 

 improbable that a slight rise of the coast has taken place in recent 

 times, and that this has helped in blocking up the mouth of these 

 streams. The former insular condition of Dinas Head — which is 

 separated from the mainland merely by a peculiar trench-like 

 valley now never occupied by the sea, though only a few feet above 

 the sea-level — points to an uplift along the coast to the extent of a 

 few feet ; the ' Slade ' at Fishguard likewise appears to have been 

 formerly a sea-inlet, and the character and shape of its banks and 

 of the sides of the Dinas valley look as if they were due to marine 

 denudation rather than to subaerial waste. The structure and 

 relations of the watercourses, tunnels, and rocky platforms at Pwll 

 y Wrach (the Witches' Cauldron), on the coast between Newport 

 and Cardigan, seem to require for their explanation a change of 

 sea-level in comparatively recent times. It is premature to go 

 further than to throw out a suggestion on this point ; the subject 

 offers, however, a promising field for investigation. 



The watershed between the Gwaen and Clydach rivers is very 

 low, and the exact point at which the waters divide to flow in 

 opposite directions is near Llanerch, S.W. of Cilgwyn, in a narrow 

 gorge. The Clydach is a transverse stream, with its course lying 

 across the strike of the strata ; it falls into the Nevern about | mile 

 east of Newport town. The drainage of the northern slopes of the 

 high ground is conducted into the sea by short transverse streams 

 opening into such bays as Aber Khigian, Aber Fforest, Aber Bach to 

 the east of Fishguard, and Aber Felin and Porth Sychan on Strumble 

 Head. 



The lines of greatest elevation follow the outcrop of the igneous 

 rocks, culminating in Garn Fawr in the west, which rises into a 

 bare rugged hill 699 feet high, and in Cam Ingle to the east 

 reaching a height of nearly 1200 feet. The whole of the Llanllawer 

 Mountains (Mynydd Melyn, Pare Mawr, Mynydd Caregog, etc.) 

 forms a ridge between 800 and 1100 feet high, averaging about 

 950 feet for the greater part of its length. Its abrupt termination 

 east and west is due to the thinning-out of the lenticular masses of 

 intrusive rock. 



Y. Stratigraphy and Petrography. 



(a) The Sedimentary Rocks. 



Though slaty rocks are abundant in this area, they rarely crop 

 out on the surface inland ; in the sea-cliffs, on the other hand, fine 

 sections are exposed, but, unfortunately, they are very barren of 

 organic remains, despite the fact that many of the beds possess 

 a very favourable appearance for the preservation of fossils. In the 



