ft'om North Cornwall. 



159 



referable to the genus Agoniatites.^ No signs of sculpture are 

 observable on the side of the body-chamber that is figured, but on 

 the opposite side on the outer portion of the lateral area there are 

 faint regularly-spaced striae, which are coincident in direction with 

 the septa on the side, but are strongly projected forwards nearer the 

 periphery. This genus is highly characteristic of, if not strictly 

 confined to, the Middle Devonian. 



Phillips ^ figured and described from South Devon examples of 

 this genus under the names Goniatites inconstans (p. 123, pi. li, 

 fig. 238) and Goniatiles transitorhis (p. 14:0, pi. Ix, fig. 227*'), 

 whilst Whidborne ^ described and figured in addition to these two 

 other forms Goniatites ohliquus (p. 56, pi. v, figs. 1-3) and 

 Goniatites fulguralis (p. 59, pi. v, figs. 4, 4a), which are also 

 referable to this genus,* but the present specimen does not appear to 



Fig. 2. — Agoniatites sp., lateral aspect of internal cast of body -chamber and of two 

 preceding chambers. 2a, posterior view of base of body-chamber of the same 

 specimen, showing form of septal surface, the small median lobe being crushed 

 a little to the right side of the specimen. Cant Hill, St. Minver, N. Cornwall. 

 Drawn of two-thirds of the natural size. 



be referable to any of these forms. It seems to be comparable 

 rather with such forms as Barrande's Goniatites bohemicus ^ and 

 G. tahidoides,^ being, however, more inflated than the latter and 

 possibly not so coarsely ornamented as the former. Both of 

 Bari'ande's forms come from his Etage G, that is, from the Eifelian 

 or lower portion of the Middle Devonian. Whilst, therefore, the 



1 F. B. Meek: U.S. Geol. Explor. 40th Parallel, vol. iv (1877), pt. 1, p. 99. 



^ J. Phillips : " Figures and Descriptions of the Palaeozoic Fossils of Cornwall, 

 Devon, and West Somerset" (Mem. Geol. Surv.), 1841. 



3 " Monograph of the Devonian Fauna of the South of England" (Pal. Soc.), 

 pt. ii (1890). 



* Hokapfel (Abhandl. d. k. Preuss. geol. Landesanst., Neue Folge, Heft 16, 

 1895, p. 55 et seqq.) unites all these forms into one species — with several varieties — 

 for which he retains Phillips's name inconstans, a species which he states to be 

 confined to the Upper Middle Devonian. 



5 J. Barrande : Syst. Sil. de la Boheme, vol. ii, pt. 1 (1867), p. 29, pi. i, 

 figs. 1-13; pi. ii, figs. 1, 2; pi. iii, figs. 15, 16; pi. ccxlii, fig. 1; pi. ccxliv! 

 figs. 3, 4. 



6 Ibid., p. 41, pi. iv, figs. 1-12. 



