GENERAL LAWS OF ORIGIN AND MIGRATION. 265 



Bearing in mind these peculiarities of the area in 

 question, we may now group in a tabular form the dis- 

 tinct specific types recognised in the Erian system, indi- 

 cating, at the same time, those which are represented by 

 identical species in the Carboniferous, those represented 

 by similar- species of the same general type, and those not 

 represented at all. For example, Calamites cannwformis 

 extends as a species into the Carboniferous ; Asterophyl- 

 Utes latifolia does not so extend, but is represented by 

 closely allied species of the same type ; Nematophyton 

 disappears altogether before we reach the Carboniferous. 



Table of Erian and Carboniferous Specific Types, 



Erian types. Represented in 

 Carboniferous — 



1. Syringoxylon mirabile ? 



2. Nematoxylon 



3. Nematophyton 



4. Aporoxylon 



5. Ormoxylon 



6. Dadoxylon 



7. Sigillaria Vanuxemii . . 



8. S. palpebra 



9. Didymophyllum 



10. Calamodendron 



11. Calamites transitionis. . 



12. 0. cannsef ormis 



13. Asterophyllites scutige- 



ra 



14. A. latifolia 



15. Annularia laxa 



16. Sphenophyllum anti- 



quum 



17. Cyclostigma 



18. Arthrostigma 



19. Lepidodendron Gaspia- 



num 



20. L. corrugatum 



21. Lycopodites Matthewi . 



22. L. Richardsoni 



23. Ptilophyton Vanuxemii 



24. Lepidophloios antiquus. 



25. Psilophyton princeps . . 



26. P. robustius 



« * a 



Erian types. Represented in 

 Carboniferous — 



27. Cordaites Robbii . . . 



28. C. angustifolia . . 



29. Archseopteris Jacksoni 



30. Aneimites obtusa 



31. Platyphyllum Brownii. 



32. Cyclopteris varia 



33. C. obtusa 



34. Neuropteris polymor- 

 pha 



35. N. serrulata 



36. N. retorquata 



37. N. resecta 



I Megalopteris Dawsoni. 



39. Sphenopteris Hoening- 

 hausi 



40. S. Harttii 



41. Hymenophyllites curti- 

 lobus 



42. H. obtusilobus 



43. Alethopteris discrepans 



44. Pecopteris serrulata. . . 



45. P. preciosa 



46. Trichomanites 



47. Callipteris 



48. Cardiocarpum 



49. C. Crampii 



50. Antholithes 



51. Trigonocarpum 



