ETHERIDGE DEVONIAN ROCKS AND FOSSILS. 693 



or pass up to the Carboniferous generally. But the relationship 

 between the fossils of the southern area and those of the continental 

 Middle Devonian is more remarkable; for of the 238 species in 

 England 90 are common to the two, almost every species of coral 

 being the same, and the majority of the Brachiopoda also. Bather, 

 then, should we expect to find that the species in the Carboniferous 

 Slate are expansions of the Middle Devonian, the change in the 

 fauna, when complete, being due to a difference of province or area 

 as well as of time. We therefore look to the Devonian for the types 

 with which to compare our Carboniferous fauna, and they will be 

 found in Xorth and South Devon. 



If I am right in substantiating the succession in Xorth Devon, 

 it is impossible that the Devonian slates and hmestones of South 

 Devon can be an expansion or extension requiiing nearly con- 

 temporaneous deposition — a condition to be perhaps readily ac- 

 counted for in the case of the Carboniferous Slate and Carboniferous 

 Limestone, which were doubtless formed under very different local 

 conditions, and in one area. Such an hypothesis can scarcely be ap- 

 plied to the prior existing, lower, older, and conformable Middle 

 Devonian slates and hmestones of either Xorth or South Devon, 

 with an almost totally different fauna ; the parallel hj^^othesis may 

 be drawn and applied with relation to the Upper Devonian beds of 

 Baggy and Marwood &c. and the Coomhola group. They perhaps 

 were deposited on the same general horizon in time, under dif- 

 ferent geographical conditions, and now rest upon (in the Irish 

 and English areas) a set of sandstones which constitute the base 

 of the Upper marine Devonian series, let them be called by what 

 name we please. It is their position as well as their palaeon- 

 tological value I contend for, both of which, if rightly viewed, give 

 not only a natural but a true solution to the upward succession of 

 the Xorth Devon rocks. There is nothing in Ireland below our 

 Upper fossiliferous marine Devonian series (Irish Carboniferous 

 slate) ; and in endeavouring to make that the base of the whole of 

 the Old Bed Sandstone I believe that Brofessor Jukes has committed 

 an error, and also in endeavouiing to establish for Ireland a fossilife- 

 rous base for the Old Bed Sandstone. Our fossiliferous Lynton and 

 Ilfracombe series may, and probably do, represent in time the thick 

 Irish series of red sandstones, gritstones, and clay slates, the base 

 of which it is admitted has never been seen, and on the top of 

 which repose their Carboniferous Slates, Coomhola Grits, and our 

 Upper Devonian in part. 



I believe, therefore, that we have in Xorth Devon, and in the 

 Lynton and Ilfracombe series only, the fossiliferous representative of 

 these barren Irish Lower Old Bed Sandstones, deposited under dif- 

 ferent conditions in a different area, although apparently allied geo- 

 graphically, accounted for upon the same principle that Brofessor 

 Jukes advances relative to the lowest Carboniferous groups, and de- 

 pendent upon chronological and geographical distribution, agreement, 

 or distinction. 



I therefore stiU ask whether the fossiliferous slates, sandstones. 



