Yol. 67.] FAUNAE HORIZONS IN THE BRISTOL COALFIELD. 341 



Fig. 4. Bairdia cf. ampla (Reuss). Magnified 3 diameters. In shale 276 feet 

 below the Bedminster Great Vein, South Liberty Colliery, Bristol. 

 (Seep. 325.; 



5. Leaia leidyi, var. salteriana Jones. Roof-shales over the High Vein, 



Parkfield Series, Coalpit-Heath Colliery. Paired valves. Magnified 

 3 diameters. (See p. 325.) 



6. Leaia leidyi, var. salteriana Jones. Portion of a clustered mass, 



showing the general mode of occurrence. Natural size. 



7. Anthracomya lanceolata Hind. Uncrushed valve from the roof of the 



Badger Vein, Second or Farrington Series, Radstock. Magnified 

 1-5 diameters. (See p. 329.) 



8. Anthracoraya lanceolata Hind. Conjoined valves. Natural size. 



Radstock. 



9. Anthracoraya lanceolata Hind. Right valve somewhat flattened. 



Natural size. Ludlows Colliery, Radstock. 



10. Anthracoraya minima (Ludwig). Young shell with short hinge-line. 



Magnified 2 diameters. Upper Coal-Measures, Foxcote Colliery, 

 Radstock. (See p. 330.) 



11. Anthracoinya minima (Ludwig). Adult shell showing increased deve- 



lopment of hinge-line, marked obliquity of valve, and much wrinkled 

 periostracum crossed by lines of growth. Magnified 2 diameters. 

 Upper Coal-Measures. Foxcote Colliery, Radstock. 



12. Anthracomya minima (Ludwig). Short, somewhat quadrangular form 



with small well-developed umbo. Magnified 3 diameters. Foxcote 

 Colliery, Radstock. 



13. Anthracomya minima (Ludwig). Attached valves showing the straight 



hinge-line, and small pointed umbones which are almost in apposition. 

 Magnified 2 diameters. Ludlows Colliery, Radstock. 



14. Xaiadites elongata (Hind). Natural size. Shales over Rock or Badger 



Vein, Second Series of the Upper Coal-Measures, Writhlington 

 Colliery. (See p. 331.) 



15. Naiadites cf. carinata (Sow.). Natural size. Black shale, Easton 



Colliery. (See p. 332.) 



16. Pseudoedmondia (?) sp. nov. Attached valves. Magnified 2 diameters. 



Upper Coal-Measures, Writhlington Colliery, Radstock. (See 

 p. 332.) 



17. Xucula oblonga (M'Coy). Magnified 3 diameters. In shale, 279 feet 



below the Bedminster Great Vein, Lower Coal-Measures, South 

 Liberty Colliery, Bristol. (See p. 333.) 

 Figs. 18 & 19. Genentonum subaaitura, sp. nov. Magnified 2"5 diameters. In 

 shale, 637 feet below the Bedminster Great Vein, Lower Coal- 

 Measures, South Liberty Colliery, Bristol. (See p. 334.) 

 20 & 21. Palceoxyris helicteroides (Morris). Magnified 2 diameters. 

 Showing the spiral arrangement of the segments continued upon 

 the beak. (See p. 336.) In shale, 279 feet below the Bedminster 

 Great Vein, Lower Coal-Measures, South Liberty Colliery, Bristol. 



