
Part II. Secr. iii. (1.) § 2.] DEVONIAN. 699 
described by F. A. Roemer from the Harz, and more recently one 
has been cited from Bicken near Herborn by Von Koenen; but, as 
Beyrich points out, there may be some doubt as to whether the 
latter is not a Pterichthys.. A Ctenacanthus, seemingly undistin- 
guishable from the C. Bohemicus of Barrande’s Etage ©, has also 
been obtained from the Lower Devonian “Nereitenschichten” of 
Thuringia.* ‘Two sharks (Paledaphus devoniensis and Byssacanthus 
Gosselet?) have been obtained from the Belgian and north of France 
area, ‘The characteristic Holoptychius nobilissimus has recently been 
detected in the Psammite de Condroz, which in Belgium forms a 
characteristic sandy, portion of the Upper Devonian rocks. These 
are interesting facts, as helping to link the Devonian and Old Red 
Sandstone types together. But they are as yet too few and 
unsupported to warrant any large deduction as to stratigraphical 
correlations between these types. The fishes of the Old Red Sand- 
stone are noticed on p. 710. 
§ 2. Local Development. 
Britain.*—The name “ Devonian” was first applied by Sedgwick and 
Murchison to the rocks of North and South Devon and Cornwall, 
whence a suite of fossils was obtained which Lonsdale pronounced to be 
intermediate in character between Silurian and Carboniferous. The actual 
passage of these strata into Silurian rocks cannot be determined from 
any section, but they clearly graduate upward into Carboniferous strata. 
They have been arranged into three divisions, as in the subjoined table: 
(Pilton and Pickwell-Down Group.—Grey slate with courses of im- 
pare limestone (Pilton) passing down into yellow, brown, and red 
Upper .4 sandstones (Baggy Point, Marwood), and a series of hard grey 
| and red sandstones and micaceous flagstones at the base (Pickwell- 
{ Down, Dulverton, Morte Bay). 
(Ilfracombe Group.—Grey unfossiliferous slates (Morte Hoe, Woola- 
| combe, and Lee Bay) passing down into calcareous fossiliferous 
Mippre.{ slates and limestones (Ilfracombe, Combe Martin, Torquay, Ply- 
| mouth), resting on hard green, grey, and red grits, sandstones, and 
\ conglomerates (Hangman Hill). 
(Lynton Group.—Soft slates with thin limestone and sandstone bands 
Lower .{ (Lynton), resting on lowest schists and red grey micaceous sand- 
\ stones (Lynton, Lynmouth, Foreland, &c.). Base not seen. 
The total thickness of these rocks is given by Dr. Haughton at 9600 
feet. Their enclosed fauna numbers about 400 species, chiefly found in 
the middle group. 
Loweir.—The clay-slate of Looe, Cornwall, has yielded a species of 
Pteraspis, also Pleurodictyum problematicum. 'The lower gritty slates and 
limestone bands of North Devon contain, among other fossils, Favosites 
cervicornis, Cyathophyllum helianthoides, Petraia celtica, Pleurodictyum proble- 
maticum, Cyathocrinus (two species), Homalonotus (two species), Phacops 
laciniatus, Fenestella antiqua, Atrypa reticularis, Orthis arenata, Spirifera 
canalifera, S. levicosta, Pterinea spinosa, &c. 
The British Lower Devonian rocks appear as yet to have supplied no 
1 Zeitsch. Deutsch. Geol. Gesell. xxix. 751. 2 Op. cit. 423. 
3 Sedgewick and Murchison, Trans. Geol. Soc. 2nd ser. v. p. 633. Lonsdale, Proc. 
Geol. Soc. iii. p. 281. Etheridge, Q. J. Geol. Soc. xxiii. (1867), 568, where a copious 
bibliography up to date will be found; also Op. cit. xxxvii., Address, p. 178. 
