Dr. H. Woodward — Devonian Trilohites from Cornwall. 29' 



Mr. Howard Fox, F.G.S., of Falmouth, has lately directed 

 attention to some recent discoveries of obscure organisms from 

 the same Devonian rocks at a meeting of the Eoyal Geological 

 Society of Cornwall (November, 1899), and published afterwards 

 in the Geological Magazine (April, 1900, Dec. IV, Vol. VII, 

 pp. 145-152, PI. VII) ; he describes and figures some of the most 

 noteworthy of these, giving also a list of localities where found. 



Mr. Fox mentions the rocks both north and south of the River 

 Camel, in Padstow Harbour, where simple cup-corals and fragmentary 

 crinoidal remains have been obtained ; he also records that at 

 Trevone fossils occur at several distinct horizons — Pteraspis, 

 Orihoceras, Bactrites, Goniatites, Eitomphalus, Cardiola, Centronella, 

 Phacops, Tentacidites, StyJiola, Amplexus, Favosites, and Pachypora. 

 At West Newtrain Bay Scaphiocrinus and a Favosite coral were 

 obtained. At Mother Ivey's I3ay, Tentacidites, Centronella, Hyolithes, 

 and crinoidal stems. Porthcothan Cove, south of Trevose Head, has 

 yielded Petraia, Pleurodictyum, PJiacops, sp., and obscurely shown 

 examples of Orthoceras and Goniatites. Lower Butter Cove yields 

 similar fossils to Porthcothan and Perth Mear. Bedruthan Steps — 

 here Steganodictyum {= Pteraspis), Orthoceras, SphcBTOcrinus ; some 

 corals, Pleurodictyum, Aulopora?, Petraia occur, with Pteroconus 

 minis, etc. At Watergate or Tregurrian Bay and Beach, 2J miles 

 north of St. Columb, Porth ; also between Fowey and Polperro, the 

 slates are found to be highlj^ fossiliferous. 



HoMALONOTUs, Konig, 1825. 



Somalonotus is a very characteristic form of Trilobite, and is easily 

 distinguished from other genera, even from its nearest ally, G(dymene. 

 The peculiar trilobation of the body-rings, so conspicuous in most 

 genera, is very indistinct in JTomalonotus, especially in the thoracic 

 segments, although in some species it is better marked in the 

 pygidium. The shape of the body is elongate, convex, with steep 

 sides, and a very broad axis, scarcely distinguished from the pleurae. 

 There are thirteen body-rings, deeply grooved, and the fulcrum is 

 close to the axis in most of the species. The head is triangular, 

 with an obscure quadrate glabella slightly lobed, and a quadrate 

 labrum ; the surface of the body is scabrous, occasionally spinous. 

 The pygidium is generally narrow and pointed, except in a few 

 species which have a more rounded contour. 



Of the twenty species recorded, by far the larger number are from 

 the Silurian. The following are from the Devonian of Devon and 

 Cornwall (and two are also exotic, namely, H. Hersclieli and 

 H. Pradoamis) : — 



Somalonotus armatus, Burm, Devonian : Cornwall. 



„ Champernoionei, H. Woodw. ,, Torquay. 



,, elongatus, Salter. „ S. Devon. 



,, goniopygceiis, H. Woodw. ,, Torquay. 



,, Hersclieli, Murch. ,, Devon and S. Africa- 



„ Pradoamis, De Vern. ,, Spain. 



„ Barraiti, H. Woodw. ,, Cornwall. 



