Vol. 52.] GEOLOGY OF THE NEIGHBOURHOOD OF CARMARTHEN. 541 



Fig. 19. 0. marginata, sp. nov. A crushed and distorted specimen. Shows that 

 the course of the facial suture is probably iutrainarginal. Natural 

 size. Swansea Road stream, Carmarthen. 



20. 0. marginata, sp. nov. Hypostome ; imperfect. Natural size. Glan 



Pibwr, Carmarthen. 



21. 0. marginata, sp. nov. Counterpart of fig. 20. 



22. 0. marginata, sp. nov. Glabella of a very small specimen. Shows the 



tubercle on the occipital ring. Natural size. Glan Pibwr, Carmar- 

 then. 



23. 0. marginata, sp. nov. Shows the hypostome and free cheek. Natural 



size. Nant Pwntan, Carmarthen. 



24. 0. marginata, sp. nov. Ditto. Same locality. 



25. 0. marginata, sp. nov. Shows the eye and part of the facial suture. 



Natural size. Glan Pibwr, Carmarthen. 



26. 0. marginata, sp. nov. The glabella of a large specimen. Natural size. 



Same locality. 



Discission. 



The President congratulated the Authors on the important dis- 

 coveries which they had made. The finding of Tremadoc rocks in 

 the neighbourhood of Carmarthen was a fact of great importance, 

 and might lead to the discovery of still older rocks in that area. 

 The succession closely resembled that found in Pembrokeshire ; but 

 it was now carried farther east than had previously been done, 

 though the work of the late T. Roberts and Mr. Marr had led one 

 to anticipate that rocks at least as old as those of Arenig age would 

 be found in this area. 



Dr. Woodward congratulated the Authors on the admirable 

 series of fossils which they had collected, and especially on the 

 very beautiful species of trilobites which they had added to the 

 British fauna, in particular the specimens of Peltura punctata and 

 Ogygia marginata. The latter form recalled to him the Asaphus 

 (Ftychopyge) corndensw, Murch., referred to by Wyatt-Edgell (Geol. 

 Mag. 1&67, pp. 14-15), but this species is from the Llundeilo .Beds, 

 not from the Tremadoc. 



Mr. Marr stated that the work done by the late T. Roberts and 

 himself (and no doubt also the work of the Authors of the present 

 paper) was largely facilitated by the published maps of the Geological 

 Survey. He believed that the Tremadoc age of the beds claimed as 

 of that date was thoroughly established. The Dicranogi'aptus-ahales 

 had hitherto yielded Hartfell graptolites only. He believed that 

 Glenkiln forms had been discovered by Mr. Roberts and himself in 

 the Haverfordwest area, but they were very badly preserved and 

 not really identifiable. They should be looked for elsewhere. 



Mr. Hopkinson and Dr. Hinde also spoke. 



