PLATE XVIII. 



CARADOC AND LLANDEILO ROCKS. 



Figs. 1 — 5. Asaphus radiatiis, Salter. 



1. „ „ Largest specimen known. Berwyn Mountains. 



(Collection of Mr. Blunt, of Shrewsbury.) 



2. „ „ Small but perfect specimen, figured by M'Coy as 



A. laticostatus. Bala, North Wales. (Wood■w^ 

 Mus.) 



3. „ „ Tail, compressed. Same locality. (Mus. Pract. 



Geology.) 



4. 5. „ „ Caudal shields, shortened by pressure. Caradoc 



Slates of Louth, Ireland. 



Pig. 6. Asaphus laticostatus, M'CoY. The only specimen known. Llandeilo 



flags, Maen Goran, Builth. (Woodwardian col- 

 lection.) 



Pigs. 7 — 10. Stygina latifrons, Portlock. (Chiefly specimens figured in Decade II 



of Geol. Survey.) Tyrone. 



7. „ „ Compressed laterally; best specimen known. (Mus. 



Pract. Geology.) 



8. „ „ A httle shortened by pressure. (Mr. J. E. Lee's 



cabinet.) 



9. „ „ Epistome and labrum. (Prof. W. Thomson's cabinet.) 

 10. „ „ Dissected head, from various specimens. It shows 



there is no rostral shield. 

 Fig. 11. Stypna MurchisoncB, MuRCHisoN. Head and tail from the only 



locality known. Mount Pleasant, Carmarthen. 



