ETHERIDGE DEVONIAK ROCKS AND FOSSILS. 689 



whole, to which must be collated or equated the succeeding Carboni- 

 ferous species, to which by succession they are allied, constituting 

 one life-system, up to the close of the Permian period. It is im- 

 possible to examine the distinctive fauna of the South and North 

 Devon Devonian rocks, taken collectively and compared with their 

 equivalents in Ehenish Prussia, Belgium, and Prance, and not to 

 perceive that it is in the North Devon area, where the sequence is 

 clear, that the question of hfe- succession must ultimately be deter- 

 mined ; for in South Devon we have as yet no known Upper-Devo- 

 nian fauna, which series was so conclusively established in this 

 northern area, at Baggy, Marwood, and Croyde &c. above the 

 Pickwell sandstones, and at Petherwin, Landlake, &c. in North 

 Cornwall, by Mr. Salter, in the year 1863*. 



Upon examination of Table IX., where every known species in 

 the Northern area (including Petherwin) is given, the importance 

 of the Upper- Devonian fauna will be at once perceived, and its 

 relation to the Carboniferous appreciated. This Table shows the 

 occurrence of 194 species in the Lower, Middle, and Upper Devonian 

 series of North Devon and Petherwin ; and in the Upper-Devonian 

 column 110 are given, of which 40 of all classes pass up to and con- 

 nect the Carboniferous ; and, taking or assuming the Barnstaple or 

 passage- series in North Devon to represent the lower part of the 

 Carboniferous, we have in this area 30 species in common between 

 the two, and 40 in aU as compared with the Carboniferous generally 

 in any area. 



Having, I trust, clearly demonstrated the succession and value of 

 the Lower and Middle Devonian Eocks, and added some little to 

 what was previously known of their conditions, I am compelled to 

 notice, in support of the views advocated, the relations which the 

 fossiliferous Upper Devonian series bear to the so-called Upper Old 

 Eed Sandstone of PickweU Down &c., because it is asserted by Pro- 

 fessor Jukes that the uppermost bed of this range was in existence 

 before any of the beds containing marine Devonian fossils were de- 

 posited. No one can doubt the fact that, resting upon the upper beds 

 of the Bed Sandstones of Pickwell Down at Yention and George Ham, 

 (at the southern part of Morte Bay), we have the lowest members of 

 the Upper Devonian group conformably succeeding the green, red, 

 and grey micaceous Upper Old Red Sandstones above named ; but it 

 must not be believed that these are the lowest marine Devonian beds. 

 I have endeavoured to show, as others have done before (and, I be- 



* The carefully prepared paper by Mr. Salter (Quart. Journ. Greol. Soc. 

 vol. xix. 1863) upon this series south of Baggy, in which the whole question is 

 discussed, and its correlation with the South- Wales beds given, with also special 

 reference to the Irish group, prevents my entering upon them in any form : all 

 the species known in the Upper Devonian series are given in the Tables II. and IX., 

 and their relation to the Carboniferous series of North Devon, or the Carboni- 

 ferous Limestones of any area, is also given. I have appended a note upon the 

 passage-beds between the Old Red Sandstone and Lower Limestone Shales of the 

 Avon section, where I am disposed to believe the Upper Devonian series is repre- 

 sented by about 1000 feet of grits, shales, and impure limestones, and many 

 species which occur in the Marwood group in North Devon, but which do not 

 range higher into the Carboniferous series above, in the Bristol section. 

 VOL. XXIII. PART I. 3 A 



