Vol. 62.] EOCKS OF WESTERN CAEEMAETHENSHIRE. 625 



This is the limestone-locality mentioned by George Owen more 

 than three centuries ago. 



The beds are well developed here, some of them being upwards 

 of 6 feet thick. This outcrop is that of a large lenticle, faulted 

 against other beds all round. In the old quarry near the house 

 the beds have been worked out into the faults, which brought them 

 against Didymogrcqrtus-bifidus Beds on the north and against Bala 

 rocks on the east and south. Some of the beds are highly f ossi- 

 ferous, bands of limestone being entirely composed of Orihis. 

 Asaprfms tyrannus occurs here, but perhaps not quite so abundantly 

 as at Lower Court. Trinucleus occurs in crowds, in the tump of 

 crushed limestone by the side of the lane. 



Farther west the nearest exposure is at TVaundwrgi, 2 miles west 

 of \Yhitland, in Messrs. Marr & Roberts's ground. 



C J 



(2) North of the Anticline. — Very different from rocks of 

 the same age on the south, the Asaplms-ty rannus Beds on the north 

 are singularly devoid of calcareous matter. They here consist 

 of ash and ashy shales, compact in places, and generally abounding 

 in fossils. They lie immediately upon Didymograptus-Murchisoni 

 Beds, and the conditions under which they were deposited were so 

 uncongenial to graptolite-life that D. MurcJiisoni, so abundant in 

 the beds below, disappeared abruptly, not to reappear again. Not 

 a single specimen has been discovered, either in the ashes or in 

 the beds above them. Trilobites, however, are fairly abundant 

 in the ash-bands and in the shales, and are associated — in the 

 higher beds — with graptolites of biserial type. 



As these beds invariably follow Didymograptus-Murchisoni striped 

 flags, their outcrops will not be followed here in detail. Only such 

 exposures will be dealt with as afford the most convenient oppor- 

 tunity for the study of the beds. 



At Pant-yr-hendref Quarry, a short distance south of Mydrim, 

 the Asaphus-tyr annus Ash is quarried for road-metal and building 

 purposes ; and this is the place where it is best developed in the 

 whole district. In the fresh condition, some of the layers are fine- 

 grained, even flinty, and dark blue in colour. They weather into 

 various shades of brown, cream-colour, and even white, but they 

 generally retain their hardness. The upper beds are somewhat 

 sandy and flaggy, yielding a few graptolites. The following fossils 

 occur here : — 



Diplograptus foliaceus, Murcb . 

 Climacograptus sp. 

 Asaphus tyrannus, Murch. 

 Ogygia Buchii, Brongn. 

 Acidaspis sp. 

 Trinucleus Lloydii, Murch. 



Trinucleus fames, Salt. 

 Orthis vespertilio, Sow. 

 Lingula granulata, Phili. 

 Lingula sp. 

 Orthoceras; etc. 



Eastwards the beds are not seen in Melin-ricket Quarry, but 

 they form a tump in the field 40 yards to the north. They are ex- 

 posed in the Llysonnen Quarry opposite, and contain fair numbers 



