76 



THE SILURIAN PERIOD. 



Diagram XVIII. Silurian fossils, all reduced in size. 



1. Omphyma turbinata. Linn. 



2. Arachnophyllum typus. M'Coy. 

 3 rays of the natural size. 



4. Cyathophyllum truncatum. Linn. 



5. Favosites gothlandica. 



6. Halysites eaten ulata. Linn. 



7. Heliolites interstinctus. Wahlenberg. 



8. one of the cells natural size. 



9. Hypanthocrinus decorus. Phillips. 



10. Tentaculites ornatus. Sow. 



11. Cornulites serpularius. Schlob. 



12. Homalonotus delphinocephalus. 



Green. 



13. Calymene Blumenbachii. Brongn. 



14. Phacops caudatus. Brongn. 



15. Encrinurus punctatus. Brunn. 



1 6. Fenestella antiqua. 



17. Lingula Lewisii. Sow. 



1 8. Discina rugata. Sow. 



19. Rhynchonella navicula. Sow. 



20. Orthis elegantula. Dolman. 



21. Pentainerus galeatus. Dalman. 



22. Pentainerus oblongus. /Sow. 



23. Orthis filosa. Sow. 



24. Spirifera plicatella. Linn. 



25. Peritamerus Knightii. (S'ow. 



26. Goniophora cymbaeformis. /S'ow. 



27. Pterinea retroflexa. Wahlenberg. 



28. Ecculiomphalus laevis. Sow. 



29. Loxonema sinuosa. Sow. 



30. Euomphalus discors. /S'ow. 



31. Acroculia haliotis. Sow. 



32. Orthoceras canaliculatum. Sow. 



33. Orthoceras ibex. Sow. 



