Dr. H, Woodward — Devonian TrUohites from Cornwall. 31 



Fishes, vol. ii, writes : — " Fragments of Pteraspidian shields, not 

 sufficiently complete for precise determination, are met with in the 

 Lower Devonian of Cornwall, and were originally described as 

 fossil sponges by McCoy." ^ 



Their fish-like character was first noted by Mr. C. W. Peach 

 (Report Brit. Assoc, 1843 (1844:), Trans. Sect., p. 56), who collected 

 many specimens ; they were subsequently assigned to Pteraspis by 

 J. W. Salter (see Wyatt-Edgell, Geol. Mag., Vol. V (1868), p. 247), 

 and finally named Scaphaspis Cornubiciis by E. Ray Lankester & 

 H. Woodward (Geol. Mag., Vol. V (1868), p. 248) and J. E. 

 Lee, ibid. [2], Vol. IX (1882), p. 105, PI. Ill, Figs. 2 and 3. 

 Numerous fragments from Polperro are preserved in the Lee 

 Collection in the British Museum, and larger specimens from Fowey. 



These obscure fossils, first described as sponges by McCoy, were 

 also referred to cuttle-fishes by Roemer (1855), under the name of 

 Archceoteuthis Dunensis (Palceontographica, Dunker & von Meyer, 

 vol. iv, p. 72, tab. xiii), now referred to Scaphaspis Cornnhiciis. The 

 late Dr. S. P. Woodward (1856) called attention to the true ichthyic 

 character of Roemei-'s supposed Archceoteuthis in his " Manual of the 

 Mollusca" (p. 417). 



Phacops, Emmrich, 1845. 



Phacops latifrons (?), Bronn. 



The specimen which I refer to this species is only a fragment 

 of a small example from the mainland shore opposite Trescore 

 Island, Porthcothan, Cornwall. 



It is seen in profile ; the head is very obscure, and is followed by 

 about ten thoracic rings with rounded bevelled pleurge ; the line of 

 the median axis is indicated on the one side preserved ; the other 

 side is wanting. Length of thoracic segments 15 mm., depth of 

 same as half seen 15 mm.; length of pygidium 6 mm., depth of 

 profile seen 9 mm. ; there is a distinct raised and grooved border 

 to the pygidium, but the furrows of the coalesced segments forming 

 the tail-plate are worn away (by the sea?). 



I have referred this example to Ph. latifrons ?, doubtfully (as the 

 specimen is so imperfect), because it is a very common Devonian 

 Trilobite and has been obtained at quite a number of localities in 

 Devon and Cornwall. It is to be hoped that better specimens may 

 shortly be met with by Mr. Barratt or other Cornish geologists. 



Horizon. — Lower Devonian. Localities : Hope and Barton, South 

 Devon ; near Liskeard and Totnes, in slates with Pleurodictyum 

 problematicum. 



Upper Devonian. — Barnstaple, Croyde, Brushford, Pilton, etc., 

 abundant. Foreign localities : Rhenish Prussia, Belgium, France, 

 Russia ; Andes, South America. 



1 F. McCoy: Ann. and Mag. Nat. Hist. [2], toI. viii (1851), p. 481, and Brit. 

 Palajozoic Foss. (1851), pi. iiA, figs. 1-3. 



