ETHEKIDGE DEVONIAN ROCKS AND FOSSILS. 



651 



Species. 



North 

 Devon. 



South 

 Devon. 



West 

 Somerset, 



Favosites fibrosa, Goldf. 



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 * 



•X- 

 ■X- 



•X- 



■X 

 •X 



-x 



■X 



* 



•X- 

 •X 

 ■X 



■X 

 ■X 



* 



•X 



■X 

 •X 



* 

 * 



* 



* 



■X- 

 ■X- 



•X 

 •X 



* 



■X 



-X 

 •X 



•X 



■X 

 X- 



■X 



•X- 

 •X 



Hallia Pengellvii, iV/.-£'(?w 



HeHophyllum HaUii, M.-Edw 



Heliolites porosus, Goldf. 



Pachyphyllum Devoniense?, M.-Edw 





Alveolites suborbicularis Lam 



(Favosites) reticulatus, Blainv 



Phacops (Trimerocephalus) laevis, Miinst 





arthritica, Phill 





Athyris concentrica V. Such 



lachrynia, Sow 



AtryiDa desquamata Sow 





a^pera Schloth 





Merista plebeia Sow 





ffranulosa, Phill 



striatula Schloth 



Rensseleria strineiceps, HoRm 



Rhynchonella cuboides, Sow 





TDU2nus JStcLvti'yi ... 





Spirifera curvata Schloth 





loevicosta, Valen. 



uuda Sow 



sxieciosQ., Scloth 



Steptorhynchus crenistria, Phill 



Strophomena rhomboidalis, Wahl 



Aprnpiilia vptnsta So7/! 



Euonaphalus serpens, Phill. 





5. Species common to the Middle Devonians of North Devon, South 

 Devon, and West Somerset. — "We will now examine those species 

 that are common to the Middle or Eifelian beds of South and North 

 Devon (Table YI.) so as to show their identity, and, by the community 

 of species, to endeavour to establish still more the relations of the 

 group and the value of its middle position in North Devon. It 

 will be found that in South Devon the position of this series can 

 only be clearly determined by palaeontological research, and by no 

 other. In other words, the stratigraphical sequence in that area is 

 so obscure through disturbance, that palaeontology alone can decide 

 or guide us ; whereas, in the north, the physical sequence is clear 

 and unmistakeable, and, aided by the assemblage, condition, and 

 identity of the fossil fauna of its slates and sandstones Avith that of 

 South Devon and Western Europe, we can, I believe, firmly establish 

 the true zoological position of the rocks under examination. Know- 



