Clarke — The Naples Fauna; 111 



guished from species of the uppermost Devonian. The American species of 

 the genus bring out forcibly another fact pertaining to the time value of varia- 

 tions in the suture. Tomoceras Mitlirax, Hall, 

 just referred to as the earliest species of our 

 faunas, has acute ventral saddles ; this character 

 again appears only among the later forms of the 

 genus, Torn, peracutum of the Naples fauna, and 

 is seen also in the Torn. mitJi mcmdes, Fhkcii, of 

 the lower upper Devonian of Nassau. In one 

 other species this feature is retained, the Torn. 

 EdwinrHalU* from the upper Chemung rocks 

 of N ew York, in which, together with the feature 

 mentioned, there is a notable tendency toward the 

 obsolescence of the lateral lobe, shown in the vigmK. T»tm*r<M m*torBdH. 

 very gradual passage of the curve of the lateral saddle into that of the 

 adjoining lobe ; a feature which seems to be less atatistic than distinctly 

 gerontic. 



TORNOCERAS UNIANGULARE, Conrad (sp.). 

 Plate VIII, Figs. 15-18. 



1842 Goniatites uniangvlaris, Conrad. Jour. Acad. Nat. Sci. Phila., vol. viii, 



p. 268, pi. 1 6, fig. 4. 

 1860 Goniatits discoideus and imiangularis, Hall. Thirteenth Ann. Kept. 



N. Y. State Cab. Nat. Hist., p. 98, figs. 5, 6, 6 (bis). 

 1876 Goniatites discoideus, Hall. Illustr. Devonian Foss. pi. lxxi, figs. 1. 7. 



10-13. 



1876 Goniatites uniangularis, Hall. Idem. fig. 14; pi. lxxii, figs. 6, 7: 

 pi. lxxiv, fig. 2. 



1879 Goniatites discoideus Hall. Palaeontology of New York vol. v, pt. 2. 



pi. lxxi, figs. 1, 7, 10-13. 

 187U Goniatites uniangularis Hall. Ibid. fig. 14 ; pi. lxxii, figs. 6, 7 : 



pi. lxxiv, fig. 2. 



1885 Goniatites discoideus, Clarke. Bull. No. 16, U. S. Geol. Surv. p. 48. 



* Tomoceras Edwin- Hall i, sp. nov. This rare shell is of moderately large size, highly involute, almost but not quite 

 non-umbilicate. Whorls compressed laterally and otherwise as in normal species of Tornockras. The curve of the suture 

 as exposed over the last whorl is a notable departure from normal expressions of Tornockras, for the lateral lobe and 

 saddle are reduced to a simple curve in which both are nearly obliterated. On the other hand the ventral saddle is strong 

 and acute. The dimensions of this species are shown in the adjoining cut. The specimen is from the Chemung sandstones 

 of Nile.N. Y. 



