Vol.51.] THE COUNTRY AROUND FISHGUARD. 155 



Llanvirn Beds of Dr. Hicks, or what I should call Lower Llandeilo.' 

 Thus it is seen that this is the same set of beds as that in the 

 Blaen y Delyn quarries. These are the only two localities where 

 fossils have been found in beds below the lower volcanic series, 

 although Mr. H. Keeping and myself have carefully searched the 

 various exposures in the area. The rocks to the south, which must 

 be of Arenig age, have as yet yielded no organic remains. 



With regard to the beds above the lower volcanic series, the 

 vertical black slates on the south-eastern side of Goodwick Bay 

 have yielded obscure fossils. These slates contain softer shaly bands, 

 and in one of these soft papery bands of black shale of a very 

 rotten and crumbling character the fossils were found. Fortunately 

 the best-preserved graptolite belongs to the zonal form Didi/mo- 

 graptus Murchisoni ; so we know that we are still low down in the 

 Llandeilo — presumably still in the Lower Llandeilo, for this grap- 

 tolite is by far the most abundant fossil, the only other recognizable 

 fragment belonging to a Diplograptus. These slates strike up the 

 Goodwick valley, and in the quarries near Drim Wood are seen 

 to have taken on a sandy character. They have here suffered con- 

 siderable crumpling and alteration. 



Between these slates and the underlying volcanic series of Bigney, 

 Cwm Bach, etc., some ashy beds are found on Saddle Point and 

 again on the eastern side of Fishguard Harbour, on Castle Point. 

 These beds are of a bluish-grey colour when in an un weathered 

 condition, and are strongty cleaved across the bedding-planes, thus 

 rendering the identification of the fragmentary fossils with which 

 they are crowded extremely difficult. Inside the fort on Castle 

 Point and on the outer slopes of that headland the exposures 

 have yielded recognizable fragments of Trinuchus concentricus 

 (var. favus ?), Orthis sp., Glyptocrinus ? (stem-joints), and fragments 

 of other organisms. On the Geological Survey map these beds 

 are coloured as ' greenstone.' Their age, stratigraphically and 

 palaeontologically, is seen to be Lower Llandeilo, 1 and the non- 

 graptolitic facies of the fauna is sufficiently accounted for by the 

 lithological character of the rock. 



The volcanic beds that lie below these fossiliferous ashes and above 

 the D. Murchisoni-beds of Tower Hill must therefore be wholly 

 in the Lower Llandeilo, and, accordingly, they are stratigraphically 

 slightly higher than the tuff-bed which separates the Llanvirn 

 (Upper Arenig) from the Lower Llandeilo in Abereiddy Bay, as 

 described by Dr. Hicks (op. cit.). 



These volcanic beds are cut off to the east by the Pwll Ceunant 

 fault : this brings almost against them the great belt of Upper 



1 Certain beds of black shale at the southern end of Ramsey Island, with 

 Trinitckux, etc., which are considered by Dr. Hicks to be intermedial between 

 the Llanvirn and Lower Llandeilo, are possibly of the same age. Throughout 

 this paper it has seemed advisable to me to use the term 'Lower Llandeilo' in 

 the sense applied to it by Dr. Hicks in his description of the Abereiddy Bay 

 beds (Quart, Journ. Geol. Soc. vol. xxxi. 1875. p. 177), and to restrict the term 

 'Llanvirn.' to the Placoparia-bvaring beds, there called by him Upper Arenig. 



