324 
STJPPLEMEiST. 
Orthocerata with circular section and the remarkable American form 
described by Prof. J. Hall under the name of Gonioceras anceps” 
Barrande expresses the opinion, however, that the latter should be 
retained in a distinct group. 
Finally, Gonioceras requires further working up with better 
material than is at present available for the purpose, before any con- 
clusions can be arrived at with respect to its true aflSnities. 
Gonioceras anceps, Hall. 
1847. Goniocei'as anceps, Hall, Pal. of New York, vol. i. p. 54, pi. xiv. 
if. 1, 1 a-d. 
1849. Gonioceras anceps^ d’Orbigny, Prodr. de Pal(§ont. Stratigi’. vol. i. 
?• 2 - 
1852. Gonioceras anceps, Giebel, Fauna der Vorwelt, Baudiii. Abth. i. 
p. 263 h 
1855. Gonioceras anceps, Swallow, Geol. Surv. of Missouri (First and 
Second Annual Report), p. 114. 
1863. Orthoceras anceps Billings, Geol. of Canada, p. 150, ff. 108, a, h. 
1865. Gonioceras anceps, Kjerulf, Veiviser ved geol. excurs. i Christi- 
ania omegn. p. 9. 
1866. Gonioceras anceps, Worthen, Geol. Surv. of Illinois, vol. i. p. 146. 
1869. Orthoceras anceps, Safford, Geol. of Tennessee, p. 289. 
1873. Gonioceras anceps, Shumard, Geol. Surv. of Missouri (1855-1871), 
p. 307. 
1874. Gonioceras anceps, Barrande, Syst. Sil. de la Boheme, vol. ii. 
Texte hi. p. 786. 
1876. Gonioceras anceps, Ferd. Roemer, Lethaea Geognostica, Theh i. ' 
Leth. Palaeoz., Atlas, Taf. vi. ff. 6 a, 5 b. 
1880. Gonioceras anceps, Kjerulf & Gurlt, Geol. des siidlichen und 
mittleren Norwegen, p. 68. 
1882. Gonioceras anceps, Whitfield, in Chamberlin’s Geol. of Wis- 
consin (1873-1879), vol. iv. pt. hi. Palseont. p. 361. 
[iVb^ 1840. Orthoceras anceps, Munster, Beitrage zur Petrefactenkunde, 
Heft hi. p. 104, Taf. ix. f. 6. — 1844. Orthoceras anceps, deKoninck, 
Descrip, des Anim. Foss, du terr. Carb. de la Belgique, p. 517, 
pi. xlv. ff. 7 a, 6.] 
^p. Char. “ General form elongated, somewhat rapidly tapering 
from the base, extremely compressed ; section an eccentric ellipse, 
compressed laterally towards the extremities, and extending into 
very acute angles ; diameters as 1 to 4 or 1 to 5 ; septa composed 
^ G. anceps is placed by Giebel with “ imperfectly known and doubtful 
species.” 
2 The name “ Orthoceras anceps ” had already been employed by de Koninck 
n 1844 (Descrip, des Anim. Foss, du terr. Carb. de la Belgique, p. 517). 
