540 MISS CRCSFIELD AND MISS SKEA.T ON THE [Aug. 1 896, 



area in question is much more faulted than appears in our sketch- 

 map. 



Among the problems which demand solution, that of the relations 

 of the Bala Series of Llangunor and Mount Pleasant to the older 

 rocks is perhaps the most important. 



A comparison of the position of the grits and conglomerates in the 

 Tremadoc and Llanvirn Beds of Carmarthen with those of the 

 Tremadoc, Arenig, and Llanvirn Series of other British areas would 

 prove valuable, but to draw this comparison satisfactorily we must 

 wait until more exact palaeontological correlations can be made. 



Our warmest thanks are due to Mr. Marr — by whose advice we 

 undertook this work — for many valuable suggestions with regard to 

 it, and for his help in the identification of some of the specimens. 



We also gratefully acknowledge our indebtedness to Prof. 

 Lapworth, who has examined and named some of our graptolites. 



EXPLANATION OF PLATES XXV. & XXVI. 



Plate XXV. 



Geological sketch-map of the neighbourhood of Carmarthen. 

 Scale: 1 inch=l mile. 



Plate XXVI. 



Fig. 1. Peltura punctata, sp. nov. Shows the punctate border and a tubercle 

 on the second body-segment. X 1^. From the Tremadoc Slates, Nant- 

 y-Glasdwr, Carmarthen. 



2. P. punctata, sp. nov. X 1^. Same locality. 



3. P. punctata, sp. nov. X H, Same locality. 



4. P. punctata, sp. nov. Shows the delicate tips of the pleura. Xl^- 



Same locality. 



5. P. punctata, sp. nov. A perfect head, somewhat crushed. X 2. Same 



locality. 



6. P. punctata, sp. nov. Cast of free cheek. x2. Same locality. 



7. P. punctata, sp. nov. A large head ; the free cheeks are missing. 



Natural size. Same locality. 



8. P '. punctata, sp nov. Shows the punctate border, the glabella-furrows, 



the tubercles on the first two body-segments, and the tips of the 

 pleura all distinctly. X 1^. Same locality. 



9. P. punctata, sp. nov. A rolled-up specimen. x2. Same locality. 



10. P. punctata, sp. nov. Two pleura enlarged. X5. Same locality. 



11. Parabolinella, sp. nov. Head imperfect, the only specimen found. 



Natural size. Nant-y-Glasdwr, Carmarthen. 



12. Parabolinella, sp. nov. Counterpart of portion of fig. 11. 



13. Ogygia marginata, sp. nov. Body and tail nearly perfect. Shows the 



sabre-like tips of the pleura. Natural size. Nant Pwntan, 

 Carmarthen. 



14. 0. marginata, sp. nov. Possibly the ' forme large ' 5 . Natural size. 



Cwm Ffrwd. Carmarthen. 



15. 0. marginata, sp. nov. Natural size. Nant Pwntan, Carmarthen. 



16. 0. marginata, sp. nov. Imperfect glabella. Shows traces of furrows, 



and a tubercle on the occipital ring. Natural size. Same locality. 



17. 0. marginata, sp. nov. A j'oung specimen, much distorted. Natural 



size. Same locality. 



18. 0. marginata, sp. nov. Shows free cheek and genal spine. Natural 



size. Same locality. 



