BRITISH FOSSILS. 



11 



Explanation of Plate I. 



Figs. 1-5. Agnostus princeps, Salter, specimens from various localities and in different 

 states. 



Figs. 1, 2, are from the Lower Lingnla flags of Felyn Ehyd Waterfall near Maentwrog, 

 and only show the radiations faintly. [Fig. 1. is the most perfect known, 

 and fig. 1 a is the same magnified. Mus. Pract. Geology]. Fig. 2 is a piece 

 of the compressed slate, showing the ordinary condition of the fossils. 



Fig. 3. Variety from the Upper Lingula flag of Penmorfa, under the church. A small 

 specimen, magnified. The natural size is indicated by its side. 



Figs. 4, 5. Large specimens of the typical form with the radiations. Upper Lingula 

 flag, Carreg Wen farm, near Borth, Portmadoc. 



Figs, 6. 7. Agnostus {Condylopyge) McCoy a, Salter, from the Upper Llandeilo flag, 

 Builfch. Fig. 6 shows head and tail of a small specimen ; 6 a the same 

 magnified. Fig. 7 a large head, natural size and magnified. (Mus. Pract. 

 Geology.) 



Figs. 8, 9, 10. Agnostus {Trinodus) trinodus, SaXter. Fine specimens from the Caradoc 



rocks of Ayrshire, presented by Prof. Wyville Thomson to Mus. Pract. 



Geology. Figs 8, 9. Heads, natural size; 8a, magnified. Fig. 10. Tail 



natural size and magnified. 

 Fig. 11. Agnostus trisectus, Salter. Upper Lingula Flags, Black Shales, Malvern. 



Mr. Tennant's cabinet. 

 Fig. 12. Agnostus (Phalacroma ?) sp. Specimen from the Lower Llandeilo (Arenig 



group) of Tai hirion, W. of Bala. (Mus. Pract. Geology.) 



J. W. Salter, 



Novemhev 1864. 



