636 



PEOCEEDINGS OF THE GEOLOGICAL SOCIETY. 



and although there is poverty in the number of known forms, yet it 

 is evident that similar conditions then occurred equally favourable to 

 the laws of life, the zoological relations over this extended area 

 during the deposition of these lower beds, like those of the higher 

 members, being marked and important. 18 species are known to 

 occur in this lower series of West Somerset and North Devon ; and 

 their distribution is given in the following Table, in which are com- 

 2)ared those species occurring in beds of the same age in the Ehenish 

 provinces, Belgium, and France. It is somewhat singular that in our 

 own group we have not as yet a single known species of the class 

 Cephalopoda, no Crustacean, and, as far as we yet know, no Fish- 

 remains. 



Table III. — Species occurriv.g in the Lower Devonian Slates, Grits, 

 and Limestones of North Devon, and those found in the same group 

 on the Rhine, in Belgium, and in France. 



Species. 



British. 



Foreign. 



i 



o 



1 

 1 



1 

 1 



J 



1 

 O 



o 



-g 



i 



it 



■«■ 



a 



'So 





1. Alveolites suborbicularis, Lam 



•5S- 

 45- 



* 



* 



Mr 

 ¥r 



■5?- 



■5J- 

 ¥r 



... 





3. Petraia pluriradialis Phill 



4. Aetinocrinus tenuistriatus, Phill. . . . 



5. Fenestella antiqua, Goldf. 



6. Chonetes sordida, /Sow.jVelHardrensis, 

 Phill 



7. Orthis arcuata, Fhill. 





9. Spirifera canalifera, Falen 





11. Isevicosta, Valen 



12. Streptorhynchus crenistria ? Phill. . . . 



1 3. Pterin ea spinosa, Phill. 



14. Ctenodonta Krachtas, it/' Cot/ 



15. Pleurotomaria aspera, Sow 



16. Bellerophon striatus, Bronn 



17. Tentaculites, sp 



18. Megalodon cucullatum, Sow 



We thus see that of the 18 British species 7 are common to the 

 Lower Devonian of North Devon, and that of one or other of the 

 three European areas given in the Table, viz. Alveolites suborbicularis , 

 Favosites cervicornis, Fenestella antiqua, Chonetes sordida vel Har- 

 drensis, Spirifera canalifera, S. hysterica, and S. Icevicosta. The pau- 

 city of known species in our area may arise from want of search, and 

 also the absence of workable limestone on the Lynton group. Some 

 of these species, Nos. 1, 6, 8, 9, 10, 14, and 16, do not pass up to 



