Vol. 62.] ROCKS OF WESTERN CARMARTHENSHIRE. 611 



Trinucleus sp., etc. The relation of these beds to the grits of the 

 immediate neighbourhood is rather difficult to make out. Taking 

 the evidence of the dips, the most probable interpretation is that 

 the graptolite-beds are folded down here and cut off by a fault 

 immediately to the south. 



About If miles to the north, in the gorse-grown ground south 

 of Cilhirwydd, is a small quarry in shales, with some hard bands. 

 The shales contain a fair number of graptolites, but three bedding- 

 planes in one hard gritty band are especially crowded with 

 them : Didymograptus hirunclo, Salt., and D. patulus, Hall, can be 

 recognized. Some trilobites of the genus JEglina and aLingula also 

 occur. This exposure is within a short distance of a Didymograptus- 

 bifidus ash outcrop. 



The late Thomas Roberts reported the occurrence of 'tuning-fork' 

 graptolites at Penycoed, east of Whitland. The shales here are 

 very barren, and from their texture and colour could be taken for 

 Tetragraptus-Beds ; further, at Nant-yr-allwyn, close by, shales of 

 exactly the same character are fossiliferous, and have yielded 

 Didymograptus (?) hirundo, Salt. ; D. patulus, Hall ; D. gibberulus, 

 ]N"ich. ; Lingula ; and Palcearca. (It may be suggested that 

 Penycoed near Mydrim was meant, for at that place tuning-fork 

 graptolites do occur.) 



The shales in the bed of the stream south of Kant-yr-allwyn 

 Bridge have yielded extensiform and dendroid graptolites in several 

 localities. Extensiform graptolites have also been collected near 

 Tynewydd (east of Whitland), and at Forest. 



East of the River Eenni the beds are abundantly exposed, but, 

 as elsewhere, are sparingly fossiliferous except in certain localities. 

 The old quarry at Llwyncrwn has yielded the greatest variety of 

 fossils. Here some bands are crowded with graptolites, the following 

 having been collected and identified : — 



Didymograptus extensus, Hall. 



Dichograptus sp. 



Didymoyraptus nitidus, Hall. 



Asaphus sp. (large and possibly 



Didymograptus patulus, Hall. 



new). 



Didymograptus sparsus, Hopk. 



JEglina caliginosa. 



Didymoyraptus hirundo, Salt. 



Mglina sp. 



Tetragraptus serra, Brongn. 



Trinucleus cf. Scdgwiclcii, Salt. 



Tetragraptus Amii, Lapw. 



Ortliis sp. 



Tetragraptus Bigsbyii, Hall. 



Lingula, cf. petalon, Hicks. 



Callograptus Salter i, Hall. 



Obolella sp. 



Callograptus sp. 



Siphonotreta. 



Dendrograptus persculptus, Hopk. 



Conidaria. 



Dendroyraptus flexuosus, Hall. 



Theca. 



Dendrograptus sp. 



Orthoceras cf. sericeum, Salt. 



Ttilograptus Hicksii, Hopk. 



Caryocaris ; etc. 



Dictyograptus cf. cancellatus, Hopk. 





(possibly new). 





At Pont-y-fenni, two-thirds of a mile due south, shales and mud- 

 stones are exposed in several good sections. In the old quarry 

 above the bridge there seems to be a slight displacement. Highly- 



