ETHERIDGE— DEYOXIAN" EOCKS AXD FOSSIIS. 657 



the peculiar and typical Devonian genera are known in the Carboni- 

 ferous rocks, either in our own two areas or in the European ; the 

 prominent and characteristic species recognized everywhere, viz. 

 Calceola sandalina, Linn., Davidsonia Verneuili, Y. Buch, Merista 

 pleheia, Sow., Rensseleria stringiceps, Eoem., Refzia ferita, Y. Buch, 

 String oceplialus Burtini, Defr., Cyrtina Demarlii, Y. Buch, and 

 Uncites gryplius, Schloth., characterize the British as well as the 

 Foreign Middle Devonians ; but species of other well-known genera 

 mark equally well the unity of the middle group over Eui'ope 

 and m England. Amongst the many strictly Lower-Devonian 

 forms prominently stand out Lejytoena laticosta, Conrad, OrtJiis hip- 

 pariony.v, Yanux., and Sjpirifera cidtrijugata, E-oem., which with us 

 are confined to the Lynton group in ISTorth Devon and the equivalent 

 Looe beds in South, and appear confined to the same stage in 

 Europe. Thus, then, of the 99 known British Devonian species, 52, 

 or 50 per cent., are known to occur in Europe, and are therefore com- 

 mon to both the great areas ; and both are related to a higher or 

 succeeding system (the Carboniferous) by only the 6 species above 

 enumerated ; we must not, however, fail to again notice the above 

 8 remarkable genera with their known single representatives, which 

 so distinguish the Middle Devonian group. 



It is now equally necessary to analyze and examine the British 

 species of Devonian Brachiopoda with those of the Carboniferous, so 

 far as they are known to be common to each other, and in each of 

 the three Devonian groups separately, because it is asserted by Mr. 

 Jukes that the rock-masses which are believed and acknowledged to 

 be of Lower, Middle, and Upper Devonian age in Xorth Devon, at 

 Lynton, Ilfracombe, and Baggy (tc. are, by community of fossils and 

 by stratigraphical and physical relations, " part of the same group of 

 rocks as those called Carboniferous Slates in Ireland ;" and, more than 

 this, it is asserted that the particular and so-called Upper Devonian 

 series of Baggy and Marwood are " on the same general horizon with 

 those of the Lower Devonian slates and grits of Lynton," (S:c. &c. 

 These views are based on the similarity of the slaty and other rock- 

 masses, in both these I^orth Devonian areas, and by comparison 

 of them with that area of the South of Ireland containing Carboni- 

 ferous Slates and certain fossils. 



I have endeavoured to prove that neither fault nor anticlinal exists 

 in Xorth Devon of a nature or magnitude to invert the order of, 

 or to repeat, the beds of the two areas from south to north, and I 

 will now endeavour to show through the Brachiopoda, as I have 

 done through the Coelenterata, that there are valid grounds for not 

 receiving cither the physical or the pala^ontological interpretation 

 put upon them by Prof. Jukes ; and these will be appealed to by a 

 more complete analysis of aU the known Devonian and Carbonife- 

 rous fossils occurring in the Northern or disputed area. 



VOL. XXIII. rART I. 2 T 



