PLATE XLII. 



SILURIAN SPECIES. 

 Fig. 



\ — 5. iSfrophoviena deltoidea, Conrad. 1, 1 «. Exteriors of the valves. Caradoc ; 



Grangegeeth. 1 b. Section. 1 c. Sculpture, enlarged. 

 2. From the Chair of Kildare. 3. Internal cast of the 

 dorsal valve ; nat. size. 3 a. Enlarged. 3 b. The valve, 

 enlarged ; from a gutta-percha mould of the cast. 4. In- 

 ternal cast of ventral valve. 4 a. Shell, enlarged ; from a 

 gutta-percha mould of the cast. All from Grangegeeth, 

 County Meath. Mus. Geol. Survey of Ireland. 5. = 

 " Orthis sublavis" M'Coy, * Sil. Foss. Ireland,' pi. iii, fig. 

 19. Caheranearta, Chair of Kildare, Ireland. Sir R. 

 Griffith's Collection. 

 6 — 8. ,, arenacea, Salter, MS. 6. Exterior of ventral valve. Upper 



Llandovery ; Norbury. 6 a. Section. 6 b. Shell-sculpture, 

 enlarged. 7. Internal cast of the ventral valve. Gunwich 

 Mill, near Alfrick. 8. Ditto, from Huntley Hill. All in 

 the Mus. Pract. Geol. 

 9, 10. ,, simulans, M'Coy. 9. Exterior of the dorsal valve. 9 a. Section. 



9 b. Shell-sculpture, enlarged. 9 c. Exterior of the ventral 

 valve. 10. Muscular impressions of the ventral valve. 

 After the original figures, 'Brit. Pal. Foss.,' pi. in, figs. 

 33 — 35. Caradoc Schists of Cefn Coed. Woodwardian 

 Museum, Cambridge. 



11. „ JFaltoni, Bay. Wenlock Shale ; Falfield. 



12 — 14. „ Orbignyi, Dav. Wenlock Limestone; Dudley. 12, 14. Mus. 



Pract. Geol. 



15 — 17. ,, .^ retroflexa, Salter. Caradoc beds. 15,16. From Chair of Kildare. 



Mus. Pract. Geol. 17. From Girvan, Ayrshire. 



18, 19. „ Hollii, Dav. Caradoc beds. 18 a. Interior of ventral valve, 



enlarged from the internal cast. 19 a. From the Onny 

 section. 



20, 21. „ i(n^?da,M.'Coy. 20, 20 a, 20 b. Complete example. Caradoc beds; 



Pontyglyn DifFws, five miles from Corwen. Mr. Davies' 

 Collection. 20 c. Shell-sculpture, enlarged. 21. Internal 

 cast of the ventral valve. Glen Ceiriog. 



