1868.] NICHOLSON — CONISTON-FLAG GKAPTOLITES. 645 



Plate XX. 



Fig. 1. Fragment of GraptoUtes Sedgwickii, Portl. (var. triangulatus, Harkn.), 

 natural size. From the Coniston Flags of Skelgill. An unfortunately 

 small example has been figured here, but much larger ones are found 

 in the flags. 



2. The same, enlarged. 



3. Fragment of G.fimbriatus, Nich., natural size. From the Coniston Flags of 



Skelgill. This is a mere fragment, but its position should be reversed. 



4. The same, enlarged. 



6. Base of G.fimbriatus, enlarged. 



6. Fragment of G. priodon, Bronn, enlarged. From the Coniston Flags of 



Broughton Moor. 



7. Another specimen of G. priodon, exhibiting a somewhat different view. 



8. The same, enlarged. 



9. Imperfectly preserved specimen of G. colonus, Barr., natural size. From 



the Coniston Flags of Horton in Eibblesdale. 



10. Fragment of G. colonus. From the Coniston Grits of Helmside, near 



Dent. 



11. Nearly perfect example of G. colonus, 'Ba.rr., enlarged. From the Lower 



Ludlow rocks of Bow Bridge, near Ludlow. 



12. Fragment of GraptoUtes discretus, Nich., natural size. From the Conis- 



ton Flags of Mosedale. 



13. The same, enlarged. 



14. Another specimen of G. discretus, showing the tapering curved base, 



natural size. Many of the cellules in this specimen have vesicles 

 attached to their apices, 



15. Fragment of another specimen of the same, showing vesicular bodies, 



apparently attached to the apices of the cellules ; enlarged. 



16. Fragment of G. Nihsoni, Barr. (var. minor, Nich.), natural size. From 



the Upper Llandeilo rocks of Dumfriesshire. 



17. The same, enlarged. 



18. Fragment of G. Nilssoni, Barr., of the ordinary form, natural size. 



From the Coniston Flags of Skelgill. 



19. The same, enlarged. 



20. Fragment of G. Nilssoni, Barr. (var. major, Nich.), natural size. From 



the Upper Llandeilo rocks of Dumfriesshire. In most examples of this 

 variety the cell-mouths form a more acute angle with the axis. 



21. Portion of the same, enlarged. 



22. Fragment of G. Bokemicus, Barr., natural size. From the Coniston 



Flags of Skelgill. 



23. The same, enlarged. 



24. Base of the same, enlarged. 



25. Fragment of G. Sagittarius, Linn., enlarged. From the Coniston Flags 



of Mosedale. 



26. Complete specimen of G. Sagittarius, Linn., in its young condition, 



showing the distal prolongation of the axis, the slender curved base, 

 the resemblance of the youngest cellules to those of G. Nilssoni, Barr., 

 and the delicate radicle ; slightly enlarged. From the Upper Llandeilo 

 rocks of Garple Linn, near Beattock. 



27. Base of another specimen of G. Sagittarius, still more extensively deve- 



loped ; natural size. From the Upper Llandeilo rocks of Frenchland 

 Burn, near Moffat. 



28. Specimen of G. SedgwicJcii, Portl., coiled into a spiral the volutions of 



which lie in one plane ( = G. spiralis, Gein.) ; enlarged. From the 

 Upper Llandeilo rocks of Dumfriesshire. 



29. Small specimen of G. turriculatus, Barr., natural size. From the Conis- 



ton Flags of Mosedale. 



30. The same, enlarged. 



31 . Fragment of G. tenuis, Portl. (?), enlarged. From the Upper Llandeilo 



rocks of Dumfriesshire. 



2v2 



