PLATE XXXVIII. 



SILURIAN SPECIES. 

 Fig. 



\ — 4. Ort/iis intercostata, Vortlock. Caradoc. 1. After the original figure in the 



' Report Gcol. Londonderry,' &c., pi. xxxvi, fig. 2. Desert- 

 creat, Tyrone. 3. Another example from the same locality. 

 3 a. Enlarged. Both in the Museum of Practical Geology. 

 2. Erom Kelley, Pomeroy. Sir R. Griffith's Collection. 

 4. From Girvan, Ayrshire. Hunterian Museum, Glasgow. 



5 — 10. „ crispata,WCoj . 5 and 7. Caradoc; Tramore, Waterford. 6 and 8. 



Knockmahon, Waterford. 10. Interior of dorsal valve. 

 Trongock, Meifod, near Welshpool. 9, 9 a. Lower Llan- 

 dovery. Internal cast of the ventral valve, and external impres- 

 sion of the same valve ; from a place a quarter of a mile south- 

 east of Cwmrhydan, Wales. 



11. „ biforata, Schlotheim. Wenlock Limestone, near Dudley. 



12 — 14. ,, „ Caradoc; Craighead Quarry, near Girvan, Ayrshire. 13. 



Dorsal valve, enlarged. 14. Another specimen from the 

 same locality. Ventral valve, enlarged. 



15 — 17. „ „ \ar. fssicostata, M'Coy. Caradoc. 15, 16. From the Chair of 



Kildare. Museum of the Geol. Survey of Ireland. 17. From 

 Ketchbridge, near Llanfyllin. 



18. „ ,, var. {Sjnrifer terebratuUformis, M'Coy, ' Sil. Foss. Ireland,' 



pi. iii, fig. 26.) 



19. „ ,, var. fssicostata. Caradoc ; Cwm Gwenan-Uchaf, Llanfyllin. 



Mus. Pract. Geol. 



20. „ „ Internal cast of ventral valve. Woolhope beds ; Bogmine, 



Shelve. Mus. Pract. Geol. 



21. „ „ Interior of the ventral valve, enlarged from the cast fig. 20. 



22. „ „ Interna] cast (enlarged) of the dorsal valve. Caradoc; 



Grangegeeth, County Meath. Mus. Geol. Survey. 



23. „ „ Interiorof the dorsal valve, enlarged. Caradoc; Pentrefflymru. 



24. „ „ Internal cast of the dorsal valve. Woolhope beds ; Bogmine, 



Shelve. Mus. Pract. Geol. 



25. „ „ = " Spirifer tridens" M'Coy, ' Sil. Foss. Ireland,' pi. iii, 



fig. 27. 



26. „ Lewisii (?), var. Hiighsii, Dav. 26 a, b. Enlarged. Coniston Grit; 



Helmside, Dent. 



27. „ triaiigularis. Sow. 27 a. Enlarged, after the original specimen, ' Sil. 



Syst.,' pi. V, fig. 13. Marrington l3ingle, Cherbury (an 

 undetermined cast, see page 277). 



28. „ tricenaria, Conrad (?). 28 a. Enlarged. Piedmont Glen, Ayrshire. 



Mus. Geol. Survey. 



29. 30. „ productoides, M'Coy (an obscure species, see page 277). Knockmahon, 



Tramore, County Waterford. Sir R. Griffith's Collection. 



